/
Parameters.html
331 lines (214 loc) · 13.6 KB
/
Parameters.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>7. Model Parameters — BLM 2019-10-07 documentation</title>
<script type="text/javascript" src="_static/js/modernizr.min.js"></script>
<script type="text/javascript" id="documentation_options" data-url_root="./" src="_static/documentation_options.js"></script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<script type="text/javascript" src="_static/language_data.js"></script>
<script crossorigin="anonymous" integrity="sha256-Ae2Vz/4ePdIu6ZyI/5ZGsYnb+m0JlOmKPjt6XZ9JJkA=" type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.4/require.min.js"></script>
<script async="async" type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/latest.js?config=TeX-AMS-MML_HTMLorMML"></script>
<script type="text/x-mathjax-config">MathJax.Hub.Config({"tex2jax": {"inlineMath": [["$", "$"], ["\\(", "\\)"]], "processClass": "math|output_area", "processEscapes": true, "ignoreClass": "document"}})</script>
<script type="text/javascript" src="_static/js/theme.js"></script>
<link rel="stylesheet" href="_static/css/theme.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<link rel="stylesheet" href="_static/fix-eq.css" type="text/css" />
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Search" href="search.html" />
<link rel="next" title="8. LAI (Leaf Area Index)" href="LAI.html" />
<link rel="prev" title="6. Penman" href="Penman.html" />
</head>
<body class="wy-body-for-nav">
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-scroll">
<div class="wy-side-nav-search" >
<a href="index.html" class="icon icon-home"> BLM
</a>
<div class="version">
2019 Autumn
</div>
<div role="search">
<form id="rtd-search-form" class="wy-form" action="search.html" method="get">
<input type="text" name="q" placeholder="Search docs" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div>
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
<p class="caption"><span class="caption-text">Overview of Term 1</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="outline.html">1. Autumn 2019 Course Outline</a></li>
<li class="toctree-l1"><a class="reference internal" href="BringToClass.html">2. For Next Class Material</a></li>
<li class="toctree-l1"><a class="reference internal" href="ReadingList.html">3. Recommended Readings</a></li>
<li class="toctree-l1"><a class="reference internal" href="Assignment1.html">4. Assignment 1</a></li>
<li class="toctree-l1"><a class="reference internal" href="Assignment2.html">5. Assignment 2</a></li>
</ul>
<p class="caption"><span class="caption-text">Assignment 1 components</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="Tasks.html">1. Assignment 1 Activities</a></li>
<li class="toctree-l1"><a class="reference internal" href="DataSource.html">2. Data Sources</a></li>
</ul>
<p class="caption"><span class="caption-text">Scientific Background</span></p>
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="Glossary.html">1. Glossary</a></li>
<li class="toctree-l1"><a class="reference internal" href="SEB.html">2. Surface energy balance</a></li>
<li class="toctree-l1"><a class="reference internal" href="SEB.html#radiation-balance">3. Radiation balance</a></li>
<li class="toctree-l1"><a class="reference internal" href="SEB.html#seb-and-radiation-balance-measurements">4. SEB and Radiation Balance Measurements</a></li>
<li class="toctree-l1"><a class="reference internal" href="SEB.html#seb-and-radiation-balance-modelling">5. SEB and Radiation Balance Modelling</a></li>
<li class="toctree-l1"><a class="reference internal" href="Penman.html">6. Penman</a></li>
<li class="toctree-l1 current"><a class="current reference internal" href="#">7. Model Parameters</a><ul>
<li class="toctree-l2"><a class="reference internal" href="#albedo">7.1. Albedo</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#typical-values">7.1.1. Typical Values</a></li>
</ul>
</li>
<li class="toctree-l2"><a class="reference internal" href="#roughness-length-z-0-and-displacement-height-d">7.2. Roughness length (<span class="math notranslate nohighlight">\(z_0\)</span>) and displacement height (<span class="math notranslate nohighlight">\(d\)</span>)</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#how-does-it-vary-with-wind-direction">7.2.1. How does it vary with wind direction?</a></li>
</ul>
</li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="LAI.html">8. LAI (Leaf Area Index)</a></li>
<li class="toctree-l1"><a class="reference internal" href="stability.html">9. Stability</a></li>
<li class="toctree-l1"><a class="reference internal" href="EddyCovariance.html">10. Eddy Covariance</a></li>
<li class="toctree-l1"><a class="reference internal" href="WindProfile.html">11. Wind Profile</a></li>
<li class="toctree-l1"><a class="reference internal" href="Storage.html">12. Storage Heat Flux</a></li>
<li class="toctree-l1"><a class="reference internal" href="ModelEvaluation.html">13. Metrics for Model evaluation</a></li>
<li class="toctree-l1"><a class="reference internal" href="URAO.html">14. URAO</a></li>
<li class="toctree-l1"><a class="reference internal" href="References.html">15. References</a></li>
</ul>
<p class="caption"><span class="caption-text">Preparing a Scientific Paper</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="ScientificPaper.html">1. Scientific paper</a></li>
<li class="toctree-l1"><a class="reference internal" href="CommonMistakes.html">2. Common Mistakes: things to check</a></li>
<li class="toctree-l1"><a class="reference internal" href="OtherResources.html">3. Other Resources</a></li>
</ul>
<p class="caption"><span class="caption-text">Technical Tips</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="python.html">1. Python</a></li>
<li class="toctree-l1"><a class="reference internal" href="JupyterNotebook.html">2. Jupyter Notebook</a></li>
<li class="toctree-l1"><a class="reference internal" href="GitHub.html">3. GitHub</a></li>
<li class="toctree-l1"><a class="reference internal" href="tutorials.html">4. Python Tutorials</a></li>
</ul>
</div>
</div>
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
<nav class="wy-nav-top" aria-label="top navigation">
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="index.html">BLM</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content">
<div role="navigation" aria-label="breadcrumbs navigation">
<ul class="wy-breadcrumbs">
<li><a href="index.html">Docs</a> »</li>
<li>7. Model Parameters</li>
<li class="wy-breadcrumbs-aside">
<a href="_sources/Parameters.rst" rel="nofollow"> View page source</a>
</li>
</ul>
<hr/>
</div>
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
<div itemprop="articleBody">
<style>
/* CSS overrides for sphinx_rtd_theme */
/* 24px margin */
.nbinput.nblast,
.nboutput.nblast {
margin-bottom: 19px; /* padding has already 5px */
}
/* ... except between code cells! */
.nblast + .nbinput {
margin-top: -19px;
}
.admonition > p:before {
margin-right: 4px; /* make room for the exclamation icon */
}
/* Fix math alignment, see https://github.com/rtfd/sphinx_rtd_theme/pull/686 */
.math {
text-align: unset;
}
</style>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>Please report issues or ask questions about this site on the <a class="reference external" href="https://github.com/Urban-Meteorology-Reading/BLM/issues/new">GitHub page</a>.</p>
</div>
<div class="section" id="model-parameters">
<h1>7. Model Parameters<a class="headerlink" href="#model-parameters" title="Permalink to this headline">¶</a></h1>
<p>Land surface models use parameters to describe the surface. For example
to model the latent heat flux using the <a class="reference internal" href="Penman.html"><span class="doc">Penman Monteith equation</span></a> the following parameters are needed.</p>
<div class="section" id="albedo">
<span id="id1"></span><h2>7.1. Albedo<a class="headerlink" href="#albedo" title="Permalink to this headline">¶</a></h2>
<p>From the short-wave radiation (K), within the <a class="reference internal" href="WindProfile.html#equation-qstar">Eq.11.6</a> <a class="reference internal" href="SEB.html#radb"><span class="std std-ref">Radiation balance</span></a> the albedo (<span class="math notranslate nohighlight">\(\alpha\)</span>) is calculated:</p>
<div class="math notranslate nohighlight" id="equation-alb">
<span class="eqno">(7.1)<a class="headerlink" href="#equation-alb" title="Permalink to this equation">¶</a></span>\[\alpha= K_{\uparrow} / K_\downarrow\]</div>
<p>using the incoming (<span class="math notranslate nohighlight">\(\downarrow\)</span>) and outgoing (<span class="math notranslate nohighlight">\(\uparrow\)</span>) shortwave radiation
(K) fluxes.</p>
<div class="section" id="typical-values">
<h3>7.1.1. Typical Values<a class="headerlink" href="#typical-values" title="Permalink to this headline">¶</a></h3>
<ul class="simple">
<li><p>Land cover type</p></li>
<li><p>Time of year</p></li>
<li><p>Time of day</p></li>
<li><p>Location</p></li>
<li><p>Reference</p></li>
</ul>
</div>
</div>
<div class="section" id="roughness-length-z-0-and-displacement-height-d">
<span id="roughness"></span><h2>7.2. Roughness length (<span class="math notranslate nohighlight">\(z_0\)</span>) and displacement height (<span class="math notranslate nohighlight">\(d\)</span>)<a class="headerlink" href="#roughness-length-z-0-and-displacement-height-d" title="Permalink to this headline">¶</a></h2>
<p>If the displacement height is known, or is negligible, the logarithmic
law equation can be rearranged with observed <span class="math notranslate nohighlight">\(z_0\)</span> and mean wind
speed to allow <span class="math notranslate nohighlight">\(z_0\)</span> to be determined. As this may vary we
normally take median of a minimum of 20 results for a wind direction
sector. If you have a period with a lot of neutral conditions you may be
able to get a lot of samples rapidly.</p>
<div class="section" id="how-does-it-vary-with-wind-direction">
<h3>7.2.1. How does it vary with wind direction?<a class="headerlink" href="#how-does-it-vary-with-wind-direction" title="Permalink to this headline">¶</a></h3>
<p>A rule of thumb for calculating d is to assume it is ~0.75 <span class="math notranslate nohighlight">\(h\)</span> where <span class="math notranslate nohighlight">\(h\)</span> is
the height of the canopy. As the heights may vary with direction you can
determine how much this may vary. What are expected to be consistent
sectors?</p>
<p>The wind profile can also be used to determine <span class="math notranslate nohighlight">\(z_0\)</span> and <span class="math notranslate nohighlight">\(d\)</span>
if there are more than 2 levels in the profile. This requires fitting a
straight line (linear regression) through the data to determine the
intercept, which provides the <span class="math notranslate nohighlight">\(z_0+d\)</span> value.
See equations 1-2 in <a class="bibtex reference internal" href="References.html#grimmond1998aerodynamic" id="id2">[8]</a>.</p>
<p>For <a class="reference internal" href="References.html"><span class="doc">References</span></a> see list</p>
</div>
</div>
</div>
</div>
</div>
<footer>
<div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
<a href="LAI.html" class="btn btn-neutral float-right" title="8. LAI (Leaf Area Index)" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right"></span></a>
<a href="Penman.html" class="btn btn-neutral float-left" title="6. Penman" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left"></span> Previous</a>
</div>
<hr/>
<div role="contentinfo">
<p>
© Copyright 2019, Prof Sue Grimmond & Dr Ting Sun
</p>
</div>
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/rtfd/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
</div>
</div>
</section>
</div>
<script type="text/javascript">
jQuery(function () {
SphinxRtdTheme.Navigation.enable(true);
});
</script>
</body>
</html>