03.2_level.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 层次"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "reki 中的 `load_` 系列函数，使用 `level_type` 参数指定层次类型，使用 `level` 参数指定层次数值。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<xarray.core.options.set_options at 0x7fde5f9d98d0>"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "import xarray as xr\n",
    "import eccodes\n",
    "\n",
    "from reki.format.grib.eccodes import (\n",
    "    load_field_from_file,\n",
    "    load_message_from_file,\n",
    "    load_messages_from_file,\n",
    ")\n",
    "\n",
    "xr.set_options(display_style=\"text\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 准备数据\n",
    "\n",
    "本示例使用 GRAPES GFS 的 GRIB 2 数据为例。\n",
    "\n",
    "获取 GRAPES GFS 2020 年 4 月 19 日 00 时次 024 时效的 GRIB 2 文件路径"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "PosixPath('/sstorage1/COMMONDATA/OPER/NWPC/GRAPES_GFS_GMF/Prod-grib/2020041900/ORIG/gmf.gra.2020041900024.grb2')"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from reki.data_finder import find_local_file\n",
    "\n",
    "data_path = find_local_file(\n",
    "    \"grapes_gfs_gmf/grib2/orig\",\n",
    "    start_time=\"2020041900\",\n",
    "    forecast_time=\"024h\",\n",
    ")\n",
    "data_path"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "获取 GRAPES GFS 2020 年 4 月 19 日 00 时次 024 时效的等模式面层 GRIB 2 文件路径"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "PosixPath('/sstorage1/COMMONDATA/OPER/NWPC/GRAPES_GFS_GMF/Prod-grib/2020041821/MODELVAR/modelvar2020041900024.grb2')"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from reki.data_finder import find_local_file\n",
    "\n",
    "modelvar_path = find_local_file(\n",
    "    \"grapes_gfs_gmf/grib2/modelvar\",\n",
    "    start_time=\"2020041900\",\n",
    "    forecast_time=\"024h\",\n",
    ")\n",
    "modelvar_path"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 层次类型\n",
    "\n",
    "`level_type` 可以接收以下类型的参数：\n",
    "\n",
    "- `str`：使用 `pl`，`sfc` 或 `ml`，使用变量的 `typeOfLevel` 检索\n",
    "- `dict`：设置用于过滤的键值对\n",
    "- `list`：指定多个层次类型，列表对象支持上面两个类型"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 字符串"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "支持两种类型的字符串\n",
    "\n",
    "- 简化的层次类型，`pl`，`sfc` 和 `ml`\n",
    "- GRIB key `typeOfLevel` 的值"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### 简化层次类型\n",
    "\n",
    "`pl` 表示等压面，`sfc` 表示地面场，`ml` 表示等模式面。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "##### pl\n",
    "\n",
    "`pl` 表示等压面，单位是 `hPa`。在 nwpc-data 内部会被替换为 `dict` 类型\n",
    "\n",
    "```json\n",
    "{\n",
    "    \"typeOfFirstFixedSurface\": 100\n",
    "}\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "检索 500 hPa 的位势高度场。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;gh&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[1193.84677734, 1193.84677734, 1193.84677734, ..., 1193.84677734,\n",
       "        1193.84677734, 1193.84677734],\n",
       "       [1194.44677734, 1194.44677734, 1194.44677734, ..., 1194.44677734,\n",
       "        1194.44677734, 1194.44677734],\n",
       "       [1194.84677734, 1194.94677734, 1194.94677734, ..., 1194.74677734,\n",
       "        1194.84677734, 1194.84677734],\n",
       "       ...,\n",
       "       [1320.64677734, 1322.54677734, 1322.24677734, ..., 1320.84677734,\n",
       "        1321.24677734, 1321.34677734],\n",
       "       [1320.64677734, 1320.64677734, 1320.74677734, ..., 1320.84677734,\n",
       "        1319.94677734, 1319.64677734],\n",
       "       [1318.94677734, 1319.04677734, 1318.44677734, ..., 1318.74677734,\n",
       "        1318.94677734, 1318.74677734]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    pl          float64 850.0\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Geopotential Height\n",
       "    GRIB_shortName:                  gh\n",
       "    GRIB_cfName:                     geopotential_height\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          3\n",
       "    GRIB_parameterNumber:            5\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      850\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      gpm\n",
       "    long_name:                       Geopotential Height\n",
       "    units:                           gpm</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 'gh' (latitude: 720, longitude: 1440)>\n",
       "array([[1193.84677734, 1193.84677734, 1193.84677734, ..., 1193.84677734,\n",
       "        1193.84677734, 1193.84677734],\n",
       "       [1194.44677734, 1194.44677734, 1194.44677734, ..., 1194.44677734,\n",
       "        1194.44677734, 1194.44677734],\n",
       "       [1194.84677734, 1194.94677734, 1194.94677734, ..., 1194.74677734,\n",
       "        1194.84677734, 1194.84677734],\n",
       "       ...,\n",
       "       [1320.64677734, 1322.54677734, 1322.24677734, ..., 1320.84677734,\n",
       "        1321.24677734, 1321.34677734],\n",
       "       [1320.64677734, 1320.64677734, 1320.74677734, ..., 1320.84677734,\n",
       "        1319.94677734, 1319.64677734],\n",
       "       [1318.94677734, 1319.04677734, 1318.44677734, ..., 1318.74677734,\n",
       "        1318.94677734, 1318.74677734]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    pl          float64 850.0\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Geopotential Height\n",
       "    GRIB_shortName:                  gh\n",
       "    GRIB_cfName:                     geopotential_height\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          3\n",
       "    GRIB_parameterNumber:            5\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      850\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      gpm\n",
       "    long_name:                       Geopotential Height\n",
       "    units:                           gpm"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "h850 = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"gh\",\n",
    "    level_type=\"pl\",\n",
    "    level=850,\n",
    ")\n",
    "h850"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "检索 0.1 hPa 的温度场"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;t&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[231.63573437, 231.63573437, 231.63573437, ..., 231.63473437,\n",
       "        231.63573437, 231.63573437],\n",
       "       [231.73973438, 231.74073438, 231.74073438, ..., 231.73873438,\n",
       "        231.73873438, 231.73973438],\n",
       "       [231.83473438, 231.83573438, 231.83673437, ..., 231.83173437,\n",
       "        231.83273438, 231.83373438],\n",
       "       ...,\n",
       "       [230.46973438, 230.47073438, 230.47273438, ..., 230.46673438,\n",
       "        230.46773437, 230.46873437],\n",
       "       [230.43373438, 230.43373438, 230.43473438, ..., 230.43073438,\n",
       "        230.43173437, 230.43273437],\n",
       "       [230.44373437, 230.44373437, 230.44373437, ..., 230.44273438,\n",
       "        230.44273438, 230.44373437]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    pl          float64 0.1\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Temperature\n",
       "    GRIB_shortName:                  t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInPa\n",
       "    GRIB_level:                      10\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Temperature\n",
       "    units:                           K</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 't' (latitude: 720, longitude: 1440)>\n",
       "array([[231.63573437, 231.63573437, 231.63573437, ..., 231.63473437,\n",
       "        231.63573437, 231.63573437],\n",
       "       [231.73973438, 231.74073438, 231.74073438, ..., 231.73873438,\n",
       "        231.73873438, 231.73973438],\n",
       "       [231.83473438, 231.83573438, 231.83673437, ..., 231.83173437,\n",
       "        231.83273438, 231.83373438],\n",
       "       ...,\n",
       "       [230.46973438, 230.47073438, 230.47273438, ..., 230.46673438,\n",
       "        230.46773437, 230.46873437],\n",
       "       [230.43373438, 230.43373438, 230.43473438, ..., 230.43073438,\n",
       "        230.43173437, 230.43273437],\n",
       "       [230.44373437, 230.44373437, 230.44373437, ..., 230.44273438,\n",
       "        230.44273438, 230.44373437]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    pl          float64 0.1\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Temperature\n",
       "    GRIB_shortName:                  t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInPa\n",
       "    GRIB_level:                      10\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Temperature\n",
       "    units:                           K"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "t0p1 = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"t\",\n",
    "    level_type=\"pl\",\n",
    "    level=0.1,\n",
    ")\n",
    "t0p1"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "检索 850hPa 温度场的 GRIB 2 消息。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "t isobaricInhPa 850\n"
     ]
    }
   ],
   "source": [
    "message_t850 = load_message_from_file(\n",
    "    data_path,\n",
    "    parameter=\"t\",\n",
    "    level_type=\"pl\",\n",
    "    level=850,\n",
    ")\n",
    "print(\n",
    "    eccodes.codes_get(message_t850, \"shortName\"),\n",
    "    eccodes.codes_get(message_t850, \"typeOfLevel\"), \n",
    "    eccodes.codes_get(message_t850, \"level\"),\n",
    ")\n",
    "eccodes.codes_release(message_t850)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "##### sfc\n",
    "\n",
    "**警告**：sfc 层次类型正在开发当中。\n",
    "\n",
    "`sfc` 表示地面场，当前函数会将 `sfc` 替换为\n",
    "\n",
    "```json\n",
    "{\n",
    "    \"typeOfLevel\": \"surface\"\n",
    "}\n",
    "```\n",
    "\n",
    "检索地面温度场。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;t&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[266.82556641, 266.92556641, 266.82556641, ..., 266.90556641,\n",
       "        266.88556641, 266.92556641],\n",
       "       [266.94556641, 267.03556641, 267.00556641, ..., 266.98556641,\n",
       "        266.91556641, 266.85556641],\n",
       "       [267.04556641, 267.01556641, 267.02556641, ..., 266.99556641,\n",
       "        267.05556641, 267.06556641],\n",
       "       ...,\n",
       "       [231.75556641, 231.28556641, 231.68556641, ..., 231.52556641,\n",
       "        231.36556641, 231.55556641],\n",
       "       [231.44556641, 231.59556641, 231.45556641, ..., 231.27556641,\n",
       "        231.39556641, 231.75556641],\n",
       "       [231.25556641, 231.14556641, 231.34556641, ..., 231.26556641,\n",
       "        231.35556641, 231.19556641]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    sfc         int64 0\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Temperature\n",
       "    GRIB_shortName:                  t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                surface\n",
       "    GRIB_level:                      0\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Temperature\n",
       "    units:                           K</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 't' (latitude: 720, longitude: 1440)>\n",
       "array([[266.82556641, 266.92556641, 266.82556641, ..., 266.90556641,\n",
       "        266.88556641, 266.92556641],\n",
       "       [266.94556641, 267.03556641, 267.00556641, ..., 266.98556641,\n",
       "        266.91556641, 266.85556641],\n",
       "       [267.04556641, 267.01556641, 267.02556641, ..., 266.99556641,\n",
       "        267.05556641, 267.06556641],\n",
       "       ...,\n",
       "       [231.75556641, 231.28556641, 231.68556641, ..., 231.52556641,\n",
       "        231.36556641, 231.55556641],\n",
       "       [231.44556641, 231.59556641, 231.45556641, ..., 231.27556641,\n",
       "        231.39556641, 231.75556641],\n",
       "       [231.25556641, 231.14556641, 231.34556641, ..., 231.26556641,\n",
       "        231.35556641, 231.19556641]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    sfc         int64 0\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Temperature\n",
       "    GRIB_shortName:                  t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                surface\n",
       "    GRIB_level:                      0\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Temperature\n",
       "    units:                           K"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "t_sfc = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"t\",\n",
    "    level_type=\"sfc\",\n",
    "    level=0,\n",
    ")\n",
    "t_sfc"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "##### ml\n",
    "\n",
    "`ml` 表示模式层。当前函数会将 `ml` 替换为 GRAPES 模式的模式面数据使用的层次类型\n",
    "\n",
    "```json\n",
    "{\n",
    "    \"typeOfFirstFixedSurface\": 131\n",
    "}\n",
    "```\n",
    "\n",
    "检索 20 层温度场。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;t&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[259.23796875, 259.24796875, 259.25796875, ..., 259.24796875,\n",
       "        259.24796875, 259.24796875],\n",
       "       [258.82796875, 258.82796875, 258.83796875, ..., 258.81796875,\n",
       "        258.81796875, 258.82796875],\n",
       "       [258.47796875, 258.47796875, 258.48796875, ..., 258.46796875,\n",
       "        258.46796875, 258.47796875],\n",
       "       ...,\n",
       "       [230.32796875, 230.36796875, 230.30796875, ..., 230.36796875,\n",
       "        230.33796875, 230.35796875],\n",
       "       [230.69796875, 230.68796875, 230.69796875, ..., 230.68796875,\n",
       "        230.68796875, 230.70796875],\n",
       "       [230.95796875, 230.92796875, 231.00796875, ..., 230.97796875,\n",
       "        230.95796875, 230.96796875]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    ml          int64 20\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Temperature\n",
       "    GRIB_shortName:                  t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    131\n",
       "    GRIB_level:                      20\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Temperature\n",
       "    units:                           K</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 't' (latitude: 720, longitude: 1440)>\n",
       "array([[259.23796875, 259.24796875, 259.25796875, ..., 259.24796875,\n",
       "        259.24796875, 259.24796875],\n",
       "       [258.82796875, 258.82796875, 258.83796875, ..., 258.81796875,\n",
       "        258.81796875, 258.82796875],\n",
       "       [258.47796875, 258.47796875, 258.48796875, ..., 258.46796875,\n",
       "        258.46796875, 258.47796875],\n",
       "       ...,\n",
       "       [230.32796875, 230.36796875, 230.30796875, ..., 230.36796875,\n",
       "        230.33796875, 230.35796875],\n",
       "       [230.69796875, 230.68796875, 230.69796875, ..., 230.68796875,\n",
       "        230.68796875, 230.70796875],\n",
       "       [230.95796875, 230.92796875, 231.00796875, ..., 230.97796875,\n",
       "        230.95796875, 230.96796875]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    ml          int64 20\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Temperature\n",
       "    GRIB_shortName:                  t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    131\n",
       "    GRIB_level:                      20\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Temperature\n",
       "    units:                           K"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "t_ml20 = load_field_from_file(\n",
    "    modelvar_path,\n",
    "    parameter=\"t\",\n",
    "    level_type=\"ml\",\n",
    "    level=20,\n",
    ")\n",
    "t_ml20"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "检索第 60 层的 u 分量。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "u 131 60\n"
     ]
    }
   ],
   "source": [
    "message_u_ml60 = load_message_from_file(\n",
    "    modelvar_path,\n",
    "    parameter=\"u\",\n",
    "    level_type=\"ml\",\n",
    "    level=60,\n",
    ")\n",
    "print(\n",
    "    eccodes.codes_get(message_u_ml60, \"shortName\"),\n",
    "    eccodes.codes_get(message_u_ml60, \"typeOfFirstFixedSurface\"), \n",
    "    eccodes.codes_get(message_u_ml60, \"level\"),\n",
    ")\n",
    "eccodes.codes_release(message_u_ml60)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### typeOfLevel\n",
    "\n",
    "使用 GRIB key `typeOfLevel` 进行检索，例如：\n",
    "\n",
    "- `isobaricInhPa`\n",
    "- `isobaricInPa`\n",
    "- `surface`\n",
    "- `heightAboveGround`\n",
    "- `meanSea`\n",
    "- `depthBelowLandLayer`\n",
    "- `cloudBase`\n",
    "- `atmosphere`\n",
    "- `nominalTop`\n",
    "- ...\n",
    "         \n",
    "更多值可以访问 https://apps.ecmwf.int/codes/grib/format/edition-independent/3/ 查询。\n",
    "\n",
    "检索 2 米最高温度。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;tmax&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[266.90474609, 267.00474609, 266.91474609, ..., 266.96474609,\n",
       "        266.93474609, 266.97474609],\n",
       "       [266.99474609, 267.02474609, 267.00474609, ..., 266.98474609,\n",
       "        266.93474609, 266.94474609],\n",
       "       [266.99474609, 267.03474609, 267.02474609, ..., 266.98474609,\n",
       "        267.02474609, 267.04474609],\n",
       "       ...,\n",
       "       [233.37474609, 233.02474609, 233.04474609, ..., 233.25474609,\n",
       "        233.21474609, 233.22474609],\n",
       "       [232.92474609, 232.92474609, 232.95474609, ..., 232.85474609,\n",
       "        232.93474609, 233.11474609],\n",
       "       [232.73474609, 232.64474609, 232.78474609, ..., 232.72474609,\n",
       "        232.69474609, 232.73474609]])\n",
       "Coordinates:\n",
       "    time               datetime64[ns] 2020-04-19\n",
       "    step               timedelta64[ns] 1 days\n",
       "    valid_time         datetime64[ns] 2020-04-20\n",
       "    heightAboveGround  int64 2\n",
       "  * latitude           (latitude) float64 89.88 89.62 89.38 ... -89.62 -89.88\n",
       "  * longitude          (longitude) float64 0.0 0.25 0.5 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   max\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  0-24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Maximum temperature\n",
       "    GRIB_shortName:                  tmax\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            4\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                heightAboveGround\n",
       "    GRIB_level:                      2\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Maximum temperature\n",
       "    units:                           K</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 'tmax' (latitude: 720, longitude: 1440)>\n",
       "array([[266.90474609, 267.00474609, 266.91474609, ..., 266.96474609,\n",
       "        266.93474609, 266.97474609],\n",
       "       [266.99474609, 267.02474609, 267.00474609, ..., 266.98474609,\n",
       "        266.93474609, 266.94474609],\n",
       "       [266.99474609, 267.03474609, 267.02474609, ..., 266.98474609,\n",
       "        267.02474609, 267.04474609],\n",
       "       ...,\n",
       "       [233.37474609, 233.02474609, 233.04474609, ..., 233.25474609,\n",
       "        233.21474609, 233.22474609],\n",
       "       [232.92474609, 232.92474609, 232.95474609, ..., 232.85474609,\n",
       "        232.93474609, 233.11474609],\n",
       "       [232.73474609, 232.64474609, 232.78474609, ..., 232.72474609,\n",
       "        232.69474609, 232.73474609]])\n",
       "Coordinates:\n",
       "    time               datetime64[ns] 2020-04-19\n",
       "    step               timedelta64[ns] 1 days\n",
       "    valid_time         datetime64[ns] 2020-04-20\n",
       "    heightAboveGround  int64 2\n",
       "  * latitude           (latitude) float64 89.88 89.62 89.38 ... -89.62 -89.88\n",
       "  * longitude          (longitude) float64 0.0 0.25 0.5 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   max\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  0-24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Maximum temperature\n",
       "    GRIB_shortName:                  tmax\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            4\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                heightAboveGround\n",
       "    GRIB_level:                      2\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Maximum temperature\n",
       "    units:                           K"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "t2max = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"tmax\",\n",
    "    level_type=\"heightAboveGround\",\n",
    "    level=2,\n",
    ")\n",
    "t2max"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "检索 0- 1000m 垂直风切变。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "vwsh heightAboveGroundLayer 1000\n"
     ]
    }
   ],
   "source": [
    "message_vwsh_h1000 = load_message_from_file(\n",
    "    data_path,\n",
    "    parameter=\"vwsh\",\n",
    "    level_type=\"heightAboveGroundLayer\",\n",
    "    level=1000,\n",
    ")\n",
    "\n",
    "print(\n",
    "    eccodes.codes_get(message_vwsh_h1000, \"shortName\"),\n",
    "    eccodes.codes_get(message_vwsh_h1000, \"typeOfLevel\"), \n",
    "    eccodes.codes_get(message_vwsh_h1000, \"level\"),\n",
    ")\n",
    "eccodes.codes_release(message_vwsh_h1000)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "可以使用 `grib_ls` 命令查看 GRIB 2 文件中包含的所有层次类型。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "atmosphere  \n",
      "cloudBase   \n",
      "depthBelowLandLayer \n",
      "heightAboveGround \n",
      "heightAboveGroundLayer \n",
      "isobaricInhPa \n",
      "isobaricInPa \n",
      "meanSea     \n",
      "nominalTop  \n",
      "surface     \n"
     ]
    }
   ],
   "source": [
    "!grib_ls -p typeOfLevel {data_path} | tail -n +3 | head -n -3 | sort | uniq"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### dict\n",
    "\n",
    "GRIB 2 消息的层次类型通常由下面几个 GRIB Key 确定：\n",
    "\n",
    "- `typeOfFirstFixedSurface`\n",
    "- `scaleFactorOfFirstFixedSurface`\n",
    "- `scaledValueOfFirstFixedSurface`\n",
    "- `typeOfSecondFixedSurface`\n",
    "- `scaleFactorOfSecondFixedSurface`\n",
    "- `scaledValueOfSecondFixedSurface`\n",
    "\n",
    "nwpc-data 支持使用字典格式指定层次类型的筛选条件，包含上述 key 的键值对。\n",
    "\n",
    "GRAPES 模式的模式面数据无法直接用 `typeOfLevel` 检索。\n",
    "\n",
    "检索第 40 层模式面的湿度场。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;q&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[1.72e-05, 1.72e-05, 1.72e-05, ..., 1.72e-05, 1.72e-05, 1.72e-05],\n",
       "       [1.68e-05, 1.68e-05, 1.69e-05, ..., 1.67e-05, 1.68e-05, 1.68e-05],\n",
       "       [1.62e-05, 1.62e-05, 1.63e-05, ..., 1.61e-05, 1.61e-05, 1.61e-05],\n",
       "       ...,\n",
       "       [3.00e-07, 3.00e-07, 3.00e-07, ..., 3.00e-07, 3.00e-07, 3.00e-07],\n",
       "       [2.00e-07, 2.00e-07, 2.00e-07, ..., 2.00e-07, 2.00e-07, 2.00e-07],\n",
       "       [5.00e-07, 5.00e-07, 5.00e-07, ..., 5.00e-07, 5.00e-07, 5.00e-07]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    level_131   int64 40\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Specific humidity\n",
       "    GRIB_shortName:                  q\n",
       "    GRIB_cfName:                     specific_humidity\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          1\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    131\n",
       "    GRIB_level:                      40\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      kg kg**-1\n",
       "    long_name:                       Specific humidity\n",
       "    units:                           kg kg**-1</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 'q' (latitude: 720, longitude: 1440)>\n",
       "array([[1.72e-05, 1.72e-05, 1.72e-05, ..., 1.72e-05, 1.72e-05, 1.72e-05],\n",
       "       [1.68e-05, 1.68e-05, 1.69e-05, ..., 1.67e-05, 1.68e-05, 1.68e-05],\n",
       "       [1.62e-05, 1.62e-05, 1.63e-05, ..., 1.61e-05, 1.61e-05, 1.61e-05],\n",
       "       ...,\n",
       "       [3.00e-07, 3.00e-07, 3.00e-07, ..., 3.00e-07, 3.00e-07, 3.00e-07],\n",
       "       [2.00e-07, 2.00e-07, 2.00e-07, ..., 2.00e-07, 2.00e-07, 2.00e-07],\n",
       "       [5.00e-07, 5.00e-07, 5.00e-07, ..., 5.00e-07, 5.00e-07, 5.00e-07]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    level_131   int64 40\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Specific humidity\n",
       "    GRIB_shortName:                  q\n",
       "    GRIB_cfName:                     specific_humidity\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          1\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    131\n",
       "    GRIB_level:                      40\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      kg kg**-1\n",
       "    long_name:                       Specific humidity\n",
       "    units:                           kg kg**-1"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "q_ml40 = load_field_from_file(\n",
    "    modelvar_path,\n",
    "    parameter=\"q\",\n",
    "    level_type={\n",
    "        \"typeOfFirstFixedSurface\": 131\n",
    "    },\n",
    "    level=40,\n",
    ")\n",
    "q_ml40"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "当然，可以使用内置的 `ml` 检索模式面要素场。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### list\n",
    "\n",
    "列表表示**逻辑或**关系，要素场只要满足其中一个条件就可以符合条件。\n",
    "主要用于从文件中批量加载数据。\n",
    "\n",
    "列表对象可以是字符串或dict。\n",
    "\n",
    "检索文件中所有等压面层和 `surface` 层的温度场。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "t surface 0\n",
      "t isobaricInhPa 1000\n",
      "t isobaricInhPa 975\n",
      "t isobaricInhPa 950\n",
      "t isobaricInhPa 925\n",
      "t isobaricInhPa 900\n",
      "t isobaricInhPa 850\n",
      "t isobaricInhPa 800\n",
      "t isobaricInhPa 750\n",
      "t isobaricInhPa 700\n",
      "t isobaricInhPa 650\n",
      "t isobaricInhPa 600\n",
      "t isobaricInhPa 550\n",
      "t isobaricInhPa 500\n",
      "t isobaricInhPa 450\n",
      "t isobaricInhPa 400\n",
      "t isobaricInhPa 350\n",
      "t isobaricInhPa 300\n",
      "t isobaricInhPa 275\n",
      "t isobaricInhPa 250\n",
      "t isobaricInhPa 225\n",
      "t isobaricInhPa 200\n",
      "t isobaricInhPa 175\n",
      "t isobaricInhPa 150\n",
      "t isobaricInhPa 125\n",
      "t isobaricInhPa 100\n",
      "t isobaricInhPa 70\n",
      "t isobaricInhPa 50\n",
      "t isobaricInhPa 30\n",
      "t isobaricInhPa 20\n",
      "t isobaricInhPa 10\n",
      "t isobaricInhPa 7\n",
      "t isobaricInhPa 5\n",
      "t isobaricInhPa 4\n",
      "t isobaricInhPa 3\n",
      "t isobaricInhPa 2\n",
      "t isobaricInhPa 1\n",
      "t isobaricInhPa 1\n",
      "t isobaricInPa 50\n",
      "t isobaricInPa 20\n",
      "t isobaricInPa 10\n"
     ]
    }
   ],
   "source": [
    "tset = load_messages_from_file(\n",
    "    data_path,\n",
    "    parameter=\"t\",\n",
    "    level_type=[\"pl\", \"surface\"],\n",
    ")\n",
    "\n",
    "for t in tset:\n",
    "    print(\n",
    "        eccodes.codes_get(t, \"shortName\"),\n",
    "        eccodes.codes_get(t, \"typeOfLevel\"), \n",
    "        eccodes.codes_get(t, \"level\"),\n",
    "    )\n",
    "    eccodes.codes_release(t)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 层次值\n",
    "\n",
    "`level` 可以接收以下类型的参数：\n",
    "\n",
    "- `int` 或 `float`：数值类型\n",
    "- `list`：指定多个层次值，用于批量检索"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 数值类型\n",
    "\n",
    "默认情况下，使用 GRIB Key `level` 值进行比较，上面示例已介绍。\n",
    "\n",
    "但下面的示例中使用 `typeOfLevel=\"isobaricInhPa\"` 检索 1.5hPa 的位势高度场会失败。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "None\n"
     ]
    }
   ],
   "source": [
    "h1p5 = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"gh\",\n",
    "    level_type=\"isobaricInhPa\",\n",
    "    level=1.5,\n",
    ")\n",
    "print(h1p5)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "使用 grib_ls 命令，可以看到文件中有多个 `isobaricInhPa` 为 1 的位势高度场。\n",
    "因为 eccodes 中 `isobaricInhPa` 的 `level` 值不支持小数。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "/sstorage1/COMMONDATA/OPER/NWPC/GRAPES_GFS_GMF/Prod-grib/2020041900/ORIG/gmf.gra.2020041900024.grb2\n",
      "edition      centre       date         dataType     gridType     typeOfLevel  level        stepRange    shortName    packingType  \n",
      "2            babj         20200419     fc           regular_ll   isobaricInhPa  1            24           gh           grid_jpeg   \n",
      "2            babj         20200419     fc           regular_ll   isobaricInhPa  1            24           gh           grid_jpeg   \n",
      "2 of 837 messages in /sstorage1/COMMONDATA/OPER/NWPC/GRAPES_GFS_GMF/Prod-grib/2020041900/ORIG/gmf.gra.2020041900024.grb2\n",
      "\n",
      "2 of 837 total messages in 1 files\n"
     ]
    }
   ],
   "source": [
    "!grib_ls -w typeOfLevel=isobaricInhPa,level=1,shortName=gh {data_path}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "可以使用 `pl` 类型检索，单位是 `hPa`。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;gh&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[44355.44375, 44355.44375, 44355.44375, ..., 44355.54375,\n",
       "        44355.54375, 44355.44375],\n",
       "       [44357.54375, 44357.54375, 44357.54375, ..., 44357.64375,\n",
       "        44357.54375, 44357.54375],\n",
       "       [44359.44375, 44359.44375, 44359.44375, ..., 44359.54375,\n",
       "        44359.44375, 44359.44375],\n",
       "       ...,\n",
       "       [40583.84375, 40583.74375, 40583.74375, ..., 40583.84375,\n",
       "        40583.84375, 40583.84375],\n",
       "       [40586.94375, 40586.94375, 40586.94375, ..., 40587.04375,\n",
       "        40587.04375, 40587.04375],\n",
       "       [40590.44375, 40590.44375, 40590.44375, ..., 40590.44375,\n",
       "        40590.44375, 40590.44375]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    pl          float64 1.5\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Geopotential Height\n",
       "    GRIB_shortName:                  gh\n",
       "    GRIB_cfName:                     geopotential_height\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          3\n",
       "    GRIB_parameterNumber:            5\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      1\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      gpm\n",
       "    long_name:                       Geopotential Height\n",
       "    units:                           gpm</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 'gh' (latitude: 720, longitude: 1440)>\n",
       "array([[44355.44375, 44355.44375, 44355.44375, ..., 44355.54375,\n",
       "        44355.54375, 44355.44375],\n",
       "       [44357.54375, 44357.54375, 44357.54375, ..., 44357.64375,\n",
       "        44357.54375, 44357.54375],\n",
       "       [44359.44375, 44359.44375, 44359.44375, ..., 44359.54375,\n",
       "        44359.44375, 44359.44375],\n",
       "       ...,\n",
       "       [40583.84375, 40583.74375, 40583.74375, ..., 40583.84375,\n",
       "        40583.84375, 40583.84375],\n",
       "       [40586.94375, 40586.94375, 40586.94375, ..., 40587.04375,\n",
       "        40587.04375, 40587.04375],\n",
       "       [40590.44375, 40590.44375, 40590.44375, ..., 40590.44375,\n",
       "        40590.44375, 40590.44375]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    step        timedelta64[ns] 1 days\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    pl          float64 1.5\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Geopotential Height\n",
       "    GRIB_shortName:                  gh\n",
       "    GRIB_cfName:                     geopotential_height\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          3\n",
       "    GRIB_parameterNumber:            5\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      1\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      gpm\n",
       "    long_name:                       Geopotential Height\n",
       "    units:                           gpm"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "h1p5 = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"gh\",\n",
    "    level_type=\"pl\",\n",
    "    level=1.5,\n",
    ")\n",
    "h1p5"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 列表\n",
    "\n",
    "如果想要检索特定几个层次的要素，可以使用列表。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;gh&#x27; (pl: 5, latitude: 720, longitude: 1440)&gt;\n",
       "array([[[ -39.77480469,  -39.87480469,  -39.77480469, ...,\n",
       "          -39.87480469,  -39.87480469,  -39.87480469],\n",
       "        [ -38.77480469,  -38.77480469,  -38.77480469, ...,\n",
       "          -38.77480469,  -38.77480469,  -38.77480469],\n",
       "        [ -37.97480469,  -37.97480469,  -37.97480469, ...,\n",
       "          -37.97480469,  -37.97480469,  -37.97480469],\n",
       "        ...,\n",
       "        [ 206.52519531,  209.72519531,  209.12519531, ...,\n",
       "          207.02519531,  207.62519531,  207.72519531],\n",
       "        [ 208.42519531,  208.32519531,  208.42519531, ...,\n",
       "          208.72519531,  207.12519531,  206.52519531],\n",
       "        [ 207.52519531,  207.72519531,  206.72519531, ...,\n",
       "          207.32519531,  207.62519531,  207.32519531]],\n",
       "\n",
       "       [[ 332.74163055,  332.74163055,  332.74163055, ...,\n",
       "          332.74163055,  332.74163055,  332.74163055],\n",
       "        [ 333.64163055,  333.64163055,  333.64163055, ...,\n",
       "          333.64163055,  333.64163055,  333.64163055],\n",
       "        [ 334.44163055,  334.44163055,  334.44163055, ...,\n",
       "          334.34163055,  334.34163055,  334.34163055],\n",
       "...\n",
       "        [1320.64677734, 1322.54677734, 1322.24677734, ...,\n",
       "         1320.84677734, 1321.24677734, 1321.34677734],\n",
       "        [1320.64677734, 1320.64677734, 1320.74677734, ...,\n",
       "         1320.84677734, 1319.94677734, 1319.64677734],\n",
       "        [1318.94677734, 1319.04677734, 1318.44677734, ...,\n",
       "         1318.74677734, 1318.94677734, 1318.74677734]],\n",
       "\n",
       "       [[5202.39023438, 5202.49023438, 5202.49023438, ...,\n",
       "         5202.39023438, 5202.39023438, 5202.39023438],\n",
       "        [5196.39023438, 5196.49023438, 5196.59023438, ...,\n",
       "         5196.19023438, 5196.29023438, 5196.39023438],\n",
       "        [5191.99023438, 5192.09023438, 5192.19023438, ...,\n",
       "         5191.69023438, 5191.79023438, 5191.89023438],\n",
       "        ...,\n",
       "        [4944.39023438, 4944.39023438, 4944.39023438, ...,\n",
       "         4944.29023438, 4944.29023438, 4944.29023438],\n",
       "        [4939.99023438, 4939.99023438, 4939.99023438, ...,\n",
       "         4939.89023438, 4939.89023438, 4939.99023438],\n",
       "        [4936.19023438, 4936.19023438, 4936.19023438, ...,\n",
       "         4936.09023438, 4936.09023438, 4936.09023438]]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    step        timedelta64[ns] 1 days\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "  * pl          (pl) float64 1e+03 950.0 925.0 850.0 500.0\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Geopotential Height\n",
       "    GRIB_shortName:                  gh\n",
       "    GRIB_cfName:                     geopotential_height\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          3\n",
       "    GRIB_parameterNumber:            5\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      1000\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      gpm\n",
       "    long_name:                       Geopotential Height\n",
       "    units:                           gpm</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 'gh' (pl: 5, latitude: 720, longitude: 1440)>\n",
       "array([[[ -39.77480469,  -39.87480469,  -39.77480469, ...,\n",
       "          -39.87480469,  -39.87480469,  -39.87480469],\n",
       "        [ -38.77480469,  -38.77480469,  -38.77480469, ...,\n",
       "          -38.77480469,  -38.77480469,  -38.77480469],\n",
       "        [ -37.97480469,  -37.97480469,  -37.97480469, ...,\n",
       "          -37.97480469,  -37.97480469,  -37.97480469],\n",
       "        ...,\n",
       "        [ 206.52519531,  209.72519531,  209.12519531, ...,\n",
       "          207.02519531,  207.62519531,  207.72519531],\n",
       "        [ 208.42519531,  208.32519531,  208.42519531, ...,\n",
       "          208.72519531,  207.12519531,  206.52519531],\n",
       "        [ 207.52519531,  207.72519531,  206.72519531, ...,\n",
       "          207.32519531,  207.62519531,  207.32519531]],\n",
       "\n",
       "       [[ 332.74163055,  332.74163055,  332.74163055, ...,\n",
       "          332.74163055,  332.74163055,  332.74163055],\n",
       "        [ 333.64163055,  333.64163055,  333.64163055, ...,\n",
       "          333.64163055,  333.64163055,  333.64163055],\n",
       "        [ 334.44163055,  334.44163055,  334.44163055, ...,\n",
       "          334.34163055,  334.34163055,  334.34163055],\n",
       "...\n",
       "        [1320.64677734, 1322.54677734, 1322.24677734, ...,\n",
       "         1320.84677734, 1321.24677734, 1321.34677734],\n",
       "        [1320.64677734, 1320.64677734, 1320.74677734, ...,\n",
       "         1320.84677734, 1319.94677734, 1319.64677734],\n",
       "        [1318.94677734, 1319.04677734, 1318.44677734, ...,\n",
       "         1318.74677734, 1318.94677734, 1318.74677734]],\n",
       "\n",
       "       [[5202.39023438, 5202.49023438, 5202.49023438, ...,\n",
       "         5202.39023438, 5202.39023438, 5202.39023438],\n",
       "        [5196.39023438, 5196.49023438, 5196.59023438, ...,\n",
       "         5196.19023438, 5196.29023438, 5196.39023438],\n",
       "        [5191.99023438, 5192.09023438, 5192.19023438, ...,\n",
       "         5191.69023438, 5191.79023438, 5191.89023438],\n",
       "        ...,\n",
       "        [4944.39023438, 4944.39023438, 4944.39023438, ...,\n",
       "         4944.29023438, 4944.29023438, 4944.29023438],\n",
       "        [4939.99023438, 4939.99023438, 4939.99023438, ...,\n",
       "         4939.89023438, 4939.89023438, 4939.99023438],\n",
       "        [4936.19023438, 4936.19023438, 4936.19023438, ...,\n",
       "         4936.09023438, 4936.09023438, 4936.09023438]]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    step        timedelta64[ns] 1 days\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "  * pl          (pl) float64 1e+03 950.0 925.0 850.0 500.0\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Geopotential Height\n",
       "    GRIB_shortName:                  gh\n",
       "    GRIB_cfName:                     geopotential_height\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          3\n",
       "    GRIB_parameterNumber:            5\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      1000\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      gpm\n",
       "    long_name:                       Geopotential Height\n",
       "    units:                           gpm"
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "hset = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"gh\",\n",
    "    level_type=\"pl\",\n",
    "    level=[500, 850, 925, 950, 1000],\n",
    ")\n",
    "hset"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "`hset` 的层次维度 `pl` 没有按照列表中给定的顺序排列，需要用户手动修改维度索引。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 默认值\n",
    "\n",
    "`level_type` 和 `level` 的默认值都为 `None`。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 使用 `level_type` 默认值\n",
    "\n",
    "省略 `level_type` 在某些情况下比较有用。\n",
    "\n",
    "比如示例文件中的垂直风切变 `vwsh` 只有一种层次类型 `heightAboveGroundLayer`，可以省略该值。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;vwsh&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[2.746, 2.762, 2.749, ..., 2.732, 2.729, 2.752],\n",
       "       [2.826, 2.86 , 2.877, ..., 2.778, 2.787, 2.866],\n",
       "       [3.027, 3.06 , 3.085, ..., 2.954, 2.971, 3.029],\n",
       "       ...,\n",
       "       [0.   , 0.   , 0.   , ..., 0.   , 0.   , 0.   ],\n",
       "       [0.   , 0.   , 0.   , ..., 0.   , 0.   , 0.   ],\n",
       "       [0.   , 0.   , 0.   , ..., 0.   , 0.   , 0.   ]])\n",
       "Coordinates:\n",
       "    time                    datetime64[ns] 2020-04-19\n",
       "    step                    timedelta64[ns] 1 days\n",
       "    valid_time              datetime64[ns] 2020-04-20\n",
       "    heightAboveGroundLayer  int64 1000\n",
       "  * latitude                (latitude) float64 89.88 89.62 ... -89.62 -89.88\n",
       "  * longitude               (longitude) float64 0.0 0.25 0.5 ... 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Vertical speed shear\n",
       "    GRIB_shortName:                  vwsh\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          2\n",
       "    GRIB_parameterNumber:            25\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                heightAboveGroundLayer\n",
       "    GRIB_level:                      1000\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      s**-1\n",
       "    long_name:                       Vertical speed shear\n",
       "    units:                           s**-1</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 'vwsh' (latitude: 720, longitude: 1440)>\n",
       "array([[2.746, 2.762, 2.749, ..., 2.732, 2.729, 2.752],\n",
       "       [2.826, 2.86 , 2.877, ..., 2.778, 2.787, 2.866],\n",
       "       [3.027, 3.06 , 3.085, ..., 2.954, 2.971, 3.029],\n",
       "       ...,\n",
       "       [0.   , 0.   , 0.   , ..., 0.   , 0.   , 0.   ],\n",
       "       [0.   , 0.   , 0.   , ..., 0.   , 0.   , 0.   ],\n",
       "       [0.   , 0.   , 0.   , ..., 0.   , 0.   , 0.   ]])\n",
       "Coordinates:\n",
       "    time                    datetime64[ns] 2020-04-19\n",
       "    step                    timedelta64[ns] 1 days\n",
       "    valid_time              datetime64[ns] 2020-04-20\n",
       "    heightAboveGroundLayer  int64 1000\n",
       "  * latitude                (latitude) float64 89.88 89.62 ... -89.62 -89.88\n",
       "  * longitude               (longitude) float64 0.0 0.25 0.5 ... 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Vertical speed shear\n",
       "    GRIB_shortName:                  vwsh\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          2\n",
       "    GRIB_parameterNumber:            25\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                heightAboveGroundLayer\n",
       "    GRIB_level:                      1000\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      s**-1\n",
       "    long_name:                       Vertical speed shear\n",
       "    units:                           s**-1"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "vwsh_h1000 = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"vwsh\",\n",
    "    level=1000,\n",
    ")\n",
    "\n",
    "vwsh_h1000"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**注意**：`load_field_` 系列函数只能检索一种层次类型。如果给定的 `level` 可能对应多种层次类型，则不能保证执行会成功。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;u&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[  1.47478271,   1.28478271,   1.16478271, ...,   2.03478271,\n",
       "          1.91478271,   1.71478271],\n",
       "       [  0.74478271,   0.67478271,   0.62478271, ...,   0.95478271,\n",
       "          0.90478271,   0.83478271],\n",
       "       [  0.98478271,   0.93478271,   0.89478271, ...,   1.14478271,\n",
       "          1.10478271,   1.04478271],\n",
       "       ...,\n",
       "       [-15.72521729, -15.70521729, -15.69521729, ..., -15.77521729,\n",
       "        -15.75521729, -15.73521729],\n",
       "       [-16.00521729, -15.96521729, -15.92521729, ..., -16.05521729,\n",
       "        -16.04521729, -16.03521729],\n",
       "       [-15.38521729, -15.35521729, -15.32521729, ..., -15.38521729,\n",
       "        -15.38521729, -15.39521729]])\n",
       "Coordinates:\n",
       "    time           datetime64[ns] 2020-04-19\n",
       "    step           timedelta64[ns] 1 days\n",
       "    valid_time     datetime64[ns] 2020-04-20\n",
       "    isobaricInhPa  int64 10\n",
       "  * latitude       (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude      (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       U component of wind\n",
       "    GRIB_shortName:                  u\n",
       "    GRIB_cfName:                     eastward_wind\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          2\n",
       "    GRIB_parameterNumber:            2\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      10\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      m s**-1\n",
       "    long_name:                       U component of wind\n",
       "    units:                           m s**-1</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 'u' (latitude: 720, longitude: 1440)>\n",
       "array([[  1.47478271,   1.28478271,   1.16478271, ...,   2.03478271,\n",
       "          1.91478271,   1.71478271],\n",
       "       [  0.74478271,   0.67478271,   0.62478271, ...,   0.95478271,\n",
       "          0.90478271,   0.83478271],\n",
       "       [  0.98478271,   0.93478271,   0.89478271, ...,   1.14478271,\n",
       "          1.10478271,   1.04478271],\n",
       "       ...,\n",
       "       [-15.72521729, -15.70521729, -15.69521729, ..., -15.77521729,\n",
       "        -15.75521729, -15.73521729],\n",
       "       [-16.00521729, -15.96521729, -15.92521729, ..., -16.05521729,\n",
       "        -16.04521729, -16.03521729],\n",
       "       [-15.38521729, -15.35521729, -15.32521729, ..., -15.38521729,\n",
       "        -15.38521729, -15.39521729]])\n",
       "Coordinates:\n",
       "    time           datetime64[ns] 2020-04-19\n",
       "    step           timedelta64[ns] 1 days\n",
       "    valid_time     datetime64[ns] 2020-04-20\n",
       "    isobaricInhPa  int64 10\n",
       "  * latitude       (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude      (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       U component of wind\n",
       "    GRIB_shortName:                  u\n",
       "    GRIB_cfName:                     eastward_wind\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          2\n",
       "    GRIB_parameterNumber:            2\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      10\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      m s**-1\n",
       "    long_name:                       U component of wind\n",
       "    units:                           m s**-1"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# 10 对应多个层次类型：isobaricInhPa，isobaricInPa 和 heightAboveGround\n",
    "# 不能保证返回何种类型数据\n",
    "u = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"u\",\n",
    "    level=10,\n",
    ")\n",
    "u"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 使用 `level` 默认值\n",
    "\n",
    "省略 `level` 会加载符合 `level_type` 的所有要素场。\n",
    "\n",
    "下面示例使用 `load_field_from_file` 加载所有等压面层的温度场。\n",
    "\n",
    "注意，返回的数据包含三个维度：层次 `pl`，纬度 `latitude`，经度 `longitude`。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;t&#x27; (pl: 40, latitude: 720, longitude: 1440)&gt;\n",
       "array([[[267.29128906, 267.39128906, 267.30128906, ..., 267.35128906,\n",
       "         267.34128906, 267.38128906],\n",
       "        [267.38128906, 267.40128906, 267.37128906, ..., 267.37128906,\n",
       "         267.36128906, 267.30128906],\n",
       "        [267.34128906, 267.34128906, 267.35128906, ..., 267.30128906,\n",
       "         267.33128906, 267.35128906],\n",
       "        ...,\n",
       "        [250.12128906, 249.81128906, 249.89128906, ..., 250.04128906,\n",
       "         249.99128906, 249.99128906],\n",
       "        [249.81128906, 249.83128906, 249.82128906, ..., 249.76128906,\n",
       "         249.92128906, 249.99128906],\n",
       "        [249.76128906, 249.73128906, 249.83128906, ..., 249.77128906,\n",
       "         249.74128906, 249.78128906]],\n",
       "\n",
       "       [[265.81492187, 265.86492187, 265.80492187, ..., 265.82492188,\n",
       "         265.82492188, 265.83492188],\n",
       "        [265.74492187, 265.76492188, 265.75492187, ..., 265.73492187,\n",
       "         265.73492187, 265.73492187],\n",
       "        [265.69492187, 265.70492188, 265.70492188, ..., 265.66492188,\n",
       "         265.68492187, 265.70492188],\n",
       "...\n",
       "        [232.79939063, 232.79939063, 232.80039063, ..., 232.79639063,\n",
       "         232.79739062, 232.79839062],\n",
       "        [232.83339062, 232.83439062, 232.83439062, ..., 232.83239063,\n",
       "         232.83239063, 232.83339062],\n",
       "        [232.87439063, 232.87439063, 232.87439063, ..., 232.87339063,\n",
       "         232.87439063, 232.87439063]],\n",
       "\n",
       "       [[231.63573437, 231.63573437, 231.63573437, ..., 231.63473437,\n",
       "         231.63573437, 231.63573437],\n",
       "        [231.73973438, 231.74073438, 231.74073438, ..., 231.73873438,\n",
       "         231.73873438, 231.73973438],\n",
       "        [231.83473438, 231.83573438, 231.83673437, ..., 231.83173437,\n",
       "         231.83273438, 231.83373438],\n",
       "        ...,\n",
       "        [230.46973438, 230.47073438, 230.47273438, ..., 230.46673438,\n",
       "         230.46773437, 230.46873437],\n",
       "        [230.43373438, 230.43373438, 230.43473438, ..., 230.43073438,\n",
       "         230.43173437, 230.43273437],\n",
       "        [230.44373437, 230.44373437, 230.44373437, ..., 230.44273438,\n",
       "         230.44273438, 230.44373437]]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    step        timedelta64[ns] 1 days\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "  * pl          (pl) float64 1e+03 975.0 950.0 925.0 900.0 ... 1.0 0.5 0.2 0.1\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Temperature\n",
       "    GRIB_shortName:                  t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      1000\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Temperature\n",
       "    units:                           K</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray 't' (pl: 40, latitude: 720, longitude: 1440)>\n",
       "array([[[267.29128906, 267.39128906, 267.30128906, ..., 267.35128906,\n",
       "         267.34128906, 267.38128906],\n",
       "        [267.38128906, 267.40128906, 267.37128906, ..., 267.37128906,\n",
       "         267.36128906, 267.30128906],\n",
       "        [267.34128906, 267.34128906, 267.35128906, ..., 267.30128906,\n",
       "         267.33128906, 267.35128906],\n",
       "        ...,\n",
       "        [250.12128906, 249.81128906, 249.89128906, ..., 250.04128906,\n",
       "         249.99128906, 249.99128906],\n",
       "        [249.81128906, 249.83128906, 249.82128906, ..., 249.76128906,\n",
       "         249.92128906, 249.99128906],\n",
       "        [249.76128906, 249.73128906, 249.83128906, ..., 249.77128906,\n",
       "         249.74128906, 249.78128906]],\n",
       "\n",
       "       [[265.81492187, 265.86492187, 265.80492187, ..., 265.82492188,\n",
       "         265.82492188, 265.83492188],\n",
       "        [265.74492187, 265.76492188, 265.75492187, ..., 265.73492187,\n",
       "         265.73492187, 265.73492187],\n",
       "        [265.69492187, 265.70492188, 265.70492188, ..., 265.66492188,\n",
       "         265.68492187, 265.70492188],\n",
       "...\n",
       "        [232.79939063, 232.79939063, 232.80039063, ..., 232.79639063,\n",
       "         232.79739062, 232.79839062],\n",
       "        [232.83339062, 232.83439062, 232.83439062, ..., 232.83239063,\n",
       "         232.83239063, 232.83339062],\n",
       "        [232.87439063, 232.87439063, 232.87439063, ..., 232.87339063,\n",
       "         232.87439063, 232.87439063]],\n",
       "\n",
       "       [[231.63573437, 231.63573437, 231.63573437, ..., 231.63473437,\n",
       "         231.63573437, 231.63573437],\n",
       "        [231.73973438, 231.74073438, 231.74073438, ..., 231.73873438,\n",
       "         231.73873438, 231.73973438],\n",
       "        [231.83473438, 231.83573438, 231.83673437, ..., 231.83173437,\n",
       "         231.83273438, 231.83373438],\n",
       "        ...,\n",
       "        [230.46973438, 230.47073438, 230.47273438, ..., 230.46673438,\n",
       "         230.46773437, 230.46873437],\n",
       "        [230.43373438, 230.43373438, 230.43473438, ..., 230.43073438,\n",
       "         230.43173437, 230.43273437],\n",
       "        [230.44373437, 230.44373437, 230.44373437, ..., 230.44273438,\n",
       "         230.44273438, 230.44373437]]])\n",
       "Coordinates:\n",
       "    time        datetime64[ns] 2020-04-19\n",
       "    valid_time  datetime64[ns] 2020-04-20\n",
       "    step        timedelta64[ns] 1 days\n",
       "  * latitude    (latitude) float64 89.88 89.62 89.38 ... -89.38 -89.62 -89.88\n",
       "  * longitude   (longitude) float64 0.0 0.25 0.5 0.75 ... 359.2 359.5 359.8\n",
       "  * pl          (pl) float64 1e+03 975.0 950.0 925.0 900.0 ... 1.0 0.5 0.2 0.1\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       Temperature\n",
       "    GRIB_shortName:                  t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    pl\n",
       "    GRIB_typeOfLevel:                isobaricInhPa\n",
       "    GRIB_level:                      1000\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       Temperature\n",
       "    units:                           K"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "tset = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"t\",\n",
    "    level_type=\"pl\",\n",
    ")\n",
    "tset"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 同时使用 `level_type` 和 `level` 的默认值\n",
    "\n",
    "当文件中只有一个要素场有特定的要素名称时，可以省略 `level_type` 和 `level`。\n",
    "\n",
    "例如检索 2m 温度场。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;2t&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[266.83474609, 266.94474609, 266.85474609, ..., 266.90474609,\n",
       "        266.89474609, 266.93474609],\n",
       "       [266.94474609, 266.98474609, 266.95474609, ..., 266.95474609,\n",
       "        266.92474609, 266.86474609],\n",
       "       [266.94474609, 266.94474609, 266.95474609, ..., 266.90474609,\n",
       "        266.94474609, 266.96474609],\n",
       "       ...,\n",
       "       [233.37474609, 233.02474609, 233.04474609, ..., 233.21474609,\n",
       "        233.21474609, 233.22474609],\n",
       "       [232.92474609, 232.92474609, 232.95474609, ..., 232.84474609,\n",
       "        232.93474609, 233.11474609],\n",
       "       [232.67474609, 232.62474609, 232.77474609, ..., 232.72474609,\n",
       "        232.69474609, 232.73474609]])\n",
       "Coordinates:\n",
       "    time               datetime64[ns] 2020-04-19\n",
       "    step               timedelta64[ns] 1 days\n",
       "    valid_time         datetime64[ns] 2020-04-20\n",
       "    heightAboveGround  int64 2\n",
       "  * latitude           (latitude) float64 89.88 89.62 89.38 ... -89.62 -89.88\n",
       "  * longitude          (longitude) float64 0.0 0.25 0.5 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       2 metre temperature\n",
       "    GRIB_shortName:                  2t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                heightAboveGround\n",
       "    GRIB_level:                      2\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       2 metre temperature\n",
       "    units:                           K</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray '2t' (latitude: 720, longitude: 1440)>\n",
       "array([[266.83474609, 266.94474609, 266.85474609, ..., 266.90474609,\n",
       "        266.89474609, 266.93474609],\n",
       "       [266.94474609, 266.98474609, 266.95474609, ..., 266.95474609,\n",
       "        266.92474609, 266.86474609],\n",
       "       [266.94474609, 266.94474609, 266.95474609, ..., 266.90474609,\n",
       "        266.94474609, 266.96474609],\n",
       "       ...,\n",
       "       [233.37474609, 233.02474609, 233.04474609, ..., 233.21474609,\n",
       "        233.21474609, 233.22474609],\n",
       "       [232.92474609, 232.92474609, 232.95474609, ..., 232.84474609,\n",
       "        232.93474609, 233.11474609],\n",
       "       [232.67474609, 232.62474609, 232.77474609, ..., 232.72474609,\n",
       "        232.69474609, 232.73474609]])\n",
       "Coordinates:\n",
       "    time               datetime64[ns] 2020-04-19\n",
       "    step               timedelta64[ns] 1 days\n",
       "    valid_time         datetime64[ns] 2020-04-20\n",
       "    heightAboveGround  int64 2\n",
       "  * latitude           (latitude) float64 89.88 89.62 89.38 ... -89.62 -89.88\n",
       "  * longitude          (longitude) float64 0.0 0.25 0.5 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       2 metre temperature\n",
       "    GRIB_shortName:                  2t\n",
       "    GRIB_cfName:                     air_temperature\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          0\n",
       "    GRIB_parameterNumber:            0\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                heightAboveGround\n",
       "    GRIB_level:                      2\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      K\n",
       "    long_name:                       2 metre temperature\n",
       "    units:                           K"
      ]
     },
     "execution_count": 22,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "t2m = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"2t\",\n",
    ")\n",
    "t2m"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "检索 10m 风场 u 分量"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<pre>&lt;xarray.DataArray &#x27;10u&#x27; (latitude: 720, longitude: 1440)&gt;\n",
       "array([[ 1.05619531,  1.05219531,  1.05319531, ...,  1.09719531,\n",
       "         1.10219531,  1.09319531],\n",
       "       [ 1.29719531,  1.31319531,  1.31519531, ...,  1.31519531,\n",
       "         1.28419531,  1.25519531],\n",
       "       [ 1.27719531,  1.27219531,  1.27219531, ...,  1.27219531,\n",
       "         1.27619531,  1.27819531],\n",
       "       ...,\n",
       "       [-0.50580469, -0.48580469, -0.45380469, ..., -0.55280469,\n",
       "        -0.53680469, -0.51780469],\n",
       "       [-0.48580469, -0.45880469, -0.43280469, ..., -0.54480469,\n",
       "        -0.51580469, -0.49580469],\n",
       "       [-0.16680469, -0.15080469, -0.12380469, ..., -0.22180469,\n",
       "        -0.20380469, -0.18280469]])\n",
       "Coordinates:\n",
       "    time               datetime64[ns] 2020-04-19\n",
       "    step               timedelta64[ns] 1 days\n",
       "    valid_time         datetime64[ns] 2020-04-20\n",
       "    heightAboveGround  int64 10\n",
       "  * latitude           (latitude) float64 89.88 89.62 89.38 ... -89.62 -89.88\n",
       "  * longitude          (longitude) float64 0.0 0.25 0.5 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       10 metre U wind component\n",
       "    GRIB_shortName:                  10u\n",
       "    GRIB_cfName:                     eastward_wind\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          2\n",
       "    GRIB_parameterNumber:            2\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                heightAboveGround\n",
       "    GRIB_level:                      10\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      m s**-1\n",
       "    long_name:                       10 metre U wind component\n",
       "    units:                           m s**-1</pre>"
      ],
      "text/plain": [
       "<xarray.DataArray '10u' (latitude: 720, longitude: 1440)>\n",
       "array([[ 1.05619531,  1.05219531,  1.05319531, ...,  1.09719531,\n",
       "         1.10219531,  1.09319531],\n",
       "       [ 1.29719531,  1.31319531,  1.31519531, ...,  1.31519531,\n",
       "         1.28419531,  1.25519531],\n",
       "       [ 1.27719531,  1.27219531,  1.27219531, ...,  1.27219531,\n",
       "         1.27619531,  1.27819531],\n",
       "       ...,\n",
       "       [-0.50580469, -0.48580469, -0.45380469, ..., -0.55280469,\n",
       "        -0.53680469, -0.51780469],\n",
       "       [-0.48580469, -0.45880469, -0.43280469, ..., -0.54480469,\n",
       "        -0.51580469, -0.49580469],\n",
       "       [-0.16680469, -0.15080469, -0.12380469, ..., -0.22180469,\n",
       "        -0.20380469, -0.18280469]])\n",
       "Coordinates:\n",
       "    time               datetime64[ns] 2020-04-19\n",
       "    step               timedelta64[ns] 1 days\n",
       "    valid_time         datetime64[ns] 2020-04-20\n",
       "    heightAboveGround  int64 10\n",
       "  * latitude           (latitude) float64 89.88 89.62 89.38 ... -89.62 -89.88\n",
       "  * longitude          (longitude) float64 0.0 0.25 0.5 ... 359.2 359.5 359.8\n",
       "Attributes:\n",
       "    GRIB_edition:                    2\n",
       "    GRIB_centre:                     babj\n",
       "    GRIB_subCentre:                  0\n",
       "    GRIB_tablesVersion:              4\n",
       "    GRIB_localTablesVersion:         1\n",
       "    GRIB_dataType:                   fc\n",
       "    GRIB_dataDate:                   20200419\n",
       "    GRIB_dataTime:                   0\n",
       "    GRIB_validityDate:               20200420\n",
       "    GRIB_validityTime:               0\n",
       "    GRIB_step:                       24\n",
       "    GRIB_stepType:                   instant\n",
       "    GRIB_stepUnits:                  1\n",
       "    GRIB_stepRange:                  24\n",
       "    GRIB_endStep:                    24\n",
       "    GRIB_name:                       10 metre U wind component\n",
       "    GRIB_shortName:                  10u\n",
       "    GRIB_cfName:                     eastward_wind\n",
       "    GRIB_discipline:                 0\n",
       "    GRIB_parameterCategory:          2\n",
       "    GRIB_parameterNumber:            2\n",
       "    GRIB_gridType:                   regular_ll\n",
       "    GRIB_gridDefinitionDescription:  Latitude/longitude \n",
       "    GRIB_typeOfFirstFixedSurface:    sfc\n",
       "    GRIB_typeOfLevel:                heightAboveGround\n",
       "    GRIB_level:                      10\n",
       "    GRIB_numberOfPoints:             1036800\n",
       "    GRIB_missingValue:               9999\n",
       "    GRIB_units:                      m s**-1\n",
       "    long_name:                       10 metre U wind component\n",
       "    units:                           m s**-1"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "u10m = load_field_from_file(\n",
    "    data_path,\n",
    "    parameter=\"10u\",\n",
    ")\n",
    "u10m"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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