Dear all, I have some issues to run humidity profile retrievals with qpack and also to run the retrieval with different viewing angle.
I am using the observations from a ground based microwave radiometer with 7
channels and 8 viewing angles.
I ) Problem with different viewing angles
Fistly, I managed to retrieve temperature profiles with qpack but only with one
viewing angle. I use a
matlab program similar to the qpack_demo.m file.
So I modify the q_demo routine to include a second angle in Q.MBLOCK_ZA_GRID (
for example Q.MBLOCK_ZA_GRID= [0 48] instead of 0).
I also create the structure Y with a function similar to the y_demo function in
the qpack_demo.m file.
After creating the Y structure, I copy the brightness temperature observed by
the instrument in the Y(1).Y field: Y(1).Y=TB_mesure
but this time the size of the array TB_mesure is : 2 * 7 instead of 1* 7 (so 2
angles and 7 channels).
When I add this line, I have the error message:
Error using rqre_datatype (line 68)
Y(1).Y must be tensor1.
Error in qpack2>checkY (line 154)
rqre_datatype( Y(1).Y, @istensor1, 'Y(1).Y' );
Error in qpack2 (line 52)
empty_y = checkY( Y );
I assume this comes from the fact that there are two dimensions instead of 1
due to the addition of the new viewing angle.
Does anyone know how we can run a retrieval with multiple viewing angles ?
By the way, does the variable Y.ZA refers to the wiewing angles like
Q.MBLOCK_ZA_GRID ? (I tried to modifiy this variable to include the
second angle also.)
II) Problem with the humidity retrieval
In my ARTS simulations, I use a humidity profile directly read from a
background profile (thus it is not a profile given with the atmlab package).
When I declare the water vapor species in the q_demo file:
Q.ABS_SPECIES(2).TAG = {'H2O-PWR98'};
Q.ABS_SPECIES(2).RETRIEVE = false;
If Q.ABS_SPECIES(2).RETRIEVE is false, I have no problem during the computation
of the temperature retrieval (even if I use my own humidity profile for the
simulation of the brightness temperature).
Then, when I try to retrieve the humidity profile in addition to the
temperature profile, I changed the Q.ABS_SPECIES(2).RETRIEVE variable to true,
and I have the following error:
Run-time error in controlfile:
/tmp/atmlab-martinet-tp9a5f653c_5510_4107_adc5_2463807d555b/cfile_y.arts
Run-time error in method: atmfields_checkedCalc
All values in *vmr_field* must be >= 0.
Stopping ARTS execution.
Goodbye .
However, I checked the vmr_field of the Q.ABS_SPECIES(2).ATMDATA.GRID and all
the values look higher than 0 (see attached file) and I already used this
humidity profile
even if I did not retrieve the humidity without no problem in ARTS. Thus, I
don't really understand why I have this error.
Does anyone have on idea ?
Thank you very much for your help.
Best regards,
Pauline
----- Météo-France -----
Dr. Pauline Martinet
Chercheur CNRM/GMEI/LISA
[email protected]
Fixe : +33 561079031
Site web: https://sites.google.com/site/martinetpauline31/
q_abs_species2_atmdata_grid1.doc
Description: MS-Word document
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