Extrapolation of results beyond the heating source

[PovedaGerman]

Hi, I've run xinvert for the Gill-Matsuno problem over the maritime continent, as shown in your example. The results I've got regarding h1, u1 and v1 are constrained just to the heating source region (see attached figure), but not to the entire Indo-Pacific region as in your figures. I think the problem can be in the plotting of the wind and streamfunction, which I include below. I appreciate any help. Many thanks in advance.

##########################
import os
import matplotlib.pyplot as plt
from netCDF4 import Dataset as netcdf_dataset
import numpy as np

from cartopy import config
import cartopy.crs as ccrs
import cartopy.feature as cfeature
from cartopy.mpl.ticker import (LongitudeFormatter, LatitudeFormatter,
LatitudeLocator)

plt.figure(figsize=(40,20))

heat = Q1
lats = lat
lons = lon

skip = 1
fontsize = 16

ax = plt.axes(projection=ccrs.PlateCarree())
ax.coastlines()
ax.add_feature(cfeature.BORDERS)

Grid for Heating source - Maritime Continent

ax.gridlines(crs=ccrs.PlateCarree(), draw_labels=True,
xlocs=np.arange(-140,100, 80), ylocs=np.arange(-40, 40, 40),
x_inline=False, y_inline=False, linewidth=0.33, color='k',alpha=0.5)

Heat Source Region

cmap = plt.colormaps['jet']
ax.contourf(lons, lats, Q1, 10, transform=ccrs.PlateCarree(), cmap=cmap , levels=np.linspace(-0.05, 0.05, 10))

Contours for h1

ax.contour(lons, lats, h1, transform=ccrs.PlateCarree(), cmap='jet')

windspeed = (u1 ** 2 + v1 ** 2) ** 0.5
windspeed.rename('windspeed')

Plot the wind speed as a contour plot

ax.contour(lons, lats, windspeed, 20, cmap='jet')

Add arrows to show the wind vectors

plt.quiver(lons, lats, u1, v1, pivot='middle', width=0.0015, headwidth=1., headlength=1., minlength=1)

#Limits for Maritime Continent

ax.set_ylim([-40, 40])
ax.set_xlim([40, 200])

plt.show()

[miniufo]

Hi thanks for your interests in this. So you don't use xarray? You can install it and load your netcdf file by dset = xarray.open_dataset('data.nc') and then quickly peek the dataset by dset.u.plot(). Also, the results returned by xinvert are also xarray object and can be plotted simply as u_gill.plot()

That is not the key point. Could you please show that if your heating source is a 2D global field? If yes, the returned data will be a 2D global field. Note that do not fill the region where heat source = 0 with nan, because nan is used as land-sea mask by default.

[PovedaGerman]

Hi, many thanks for your answer. It seems that the problem has to do with the definition of longitudes and latitudes of the heating source and the region for which h1, v1 and u1 are estimated. Can you please clarify what are your:

lat, lon = xr.broadcast(ds.lat, ds.lon) for the heating source, and
lat, lon = xr.broadcast(u1.lat, u1.lon) for the impacted region

Many thanks in advance.

[miniufo]

Hi, I guess you read my notebook about Gill model at here. Now I've change a little of the notebook so that the heat source Q is a global field, and so are the h1, u1 and v1. You can follow this example because this idealized test does not need any data files.

[PovedaGerman]

It worked well. Many thanks for your help.

…

On Fri, Jun 17, 2022 at 9:24 AM Yu-Kun Qian ***@***.***> wrote: Hi, I guess you read my notebook about Gill model at here <https://github.com/miniufo/xinvert/blob/master/notebooks/2.%20Invert%20Gill-Matsuno%20model.ipynb>. Now I've change a little of the notebook so that the heat source Q is a global field, and so are the h1, u1 and v1. You can follow this example because this idealized test does not need any data files. — Reply to this email directly, view it on GitHub <#2 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AZR4U4Z6UQL7YDVIHOQ3H4TVPSDC3ANCNFSM5YX3WUAQ> . You are receiving this because you authored the thread.Message ID: ***@***.***> *Aviso legal:* El contenido de este mensaje y los archivos adjuntos son confidenciales y de uso exclusivo de la Universidad Nacional de Colombia. Se encuentran dirigidos sólo para el uso del destinatario al cual van enviados. La reproducción, lectura y/o copia se encuentran prohibidas a cualquier persona diferente a este y puede ser ilegal. Si usted lo ha recibido por error, infórmenos y elimínelo de su correo. Los Datos Personales serán tratados conforme a la Ley 1581 de 2012 y a nuestra Política de Datos Personales que podrá consultar en la página web www.unal.edu.co. Las opiniones, informaciones, conclusiones y cualquier otro tipo de dato contenido en este correo electrónico, no relacionados con la actividad de la Universidad Nacional de Colombia, se entenderá como personales y de ninguna manera son avaladas por la Universidad.

[PovedaGerman]

Hi Yu-Kun: I am using xinvert to represent the Gill-Masuno-type atmospheric flow over the wettest spot on Earth, located over the far eastern tropical Pacific and over western Colombia in South America. I am including heat sources at this region and over the Amazon river basin, and a cooling source over the cold tongue off the Peru-Ecuador eastern tropical Pacific. I am attaching a figure with the results, which gives a totally unrealistic wind flow patterns, given the lack of the Andes mountains that impede the winds from the Pacific entering into the Amazon. I'd like to know your thoughts about it. Many thanks in advance, [image: image.png] Germán

…

On Fri, Jun 17, 2022 at 9:24 AM Yu-Kun Qian ***@***.***> wrote: Hi, I guess you read my notebook about Gill model at here <https://github.com/miniufo/xinvert/blob/master/notebooks/2.%20Invert%20Gill-Matsuno%20model.ipynb>. Now I've change a little of the notebook so that the heat source Q is a global field, and so are the h1, u1 and v1. You can follow this example because this idealized test does not need any data files. — Reply to this email directly, view it on GitHub <#2 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AZR4U4Z6UQL7YDVIHOQ3H4TVPSDC3ANCNFSM5YX3WUAQ> . You are receiving this because you authored the thread.Message ID: ***@***.***> *Aviso legal:* El contenido de este mensaje y los archivos adjuntos son confidenciales y de uso exclusivo de la Universidad Nacional de Colombia. Se encuentran dirigidos sólo para el uso del destinatario al cual van enviados. La reproducción, lectura y/o copia se encuentran prohibidas a cualquier persona diferente a este y puede ser ilegal. Si usted lo ha recibido por error, infórmenos y elimínelo de su correo. Los Datos Personales serán tratados conforme a la Ley 1581 de 2012 y a nuestra Política de Datos Personales que podrá consultar en la página web www.unal.edu.co. Las opiniones, informaciones, conclusiones y cualquier otro tipo de dato contenido en este correo electrónico, no relacionados con la actividad de la Universidad Nacional de Colombia, se entenderá como personales y de ninguna manera son avaladas por la Universidad.

[miniufo]

Sorry, I cannot see your figure. Could you post it as a link?

[PovedaGerman]

This is the figure:

[miniufo]

Well, I see... The original Gill model does not take into account topographic effects. But I guess one can modify it to parameterize their effect into the model. As xinvert support topographic (see oceanic case), maybe you can prescribe the Andes as a patch of NaN and set kwarg undef=np.nan. Then you can get the flow stopped at Andes.

Also, the effects of the cooling over the cold tongue is not clear. You can invert the flow separately for the cooling source only. Generally, the flow pattern is NOT totally unrealistic to me. It still fits Gill's classical pattern in the tropics.

[PovedaGerman]

Many thanks for your insights.