Hi everyone, I am using qpack to retrieve humidity profile from microwave observations (from 22.24 GHz to 31.40 GHz).
My vertical grid goes from 1009 hPa to 0.6 hPa in 60 levels. I am surprised about the shape of the humidity jacobians for the first channel at 22.24 GHz that gives very large values at the top of the atmosphere where I would expect the jacobians to be almost zero. (see attached figure humidity_jacobians_60levels.png) I tried to used two different absorption models (PWR98 and MPM93) but I have the same problem. To avoid this large value in the stratosphere, I also tried to run my retrievals on a smaller grid only between level 1 and level 45 (~280 hPa) and now I have even larger values at 280hPa instead of 0.6 hPa (see attached figure humidity_jacobians_60levels.png). Does anyone know why I get such large values for the humidity jacobians ? Maybe there is something wrong when I define my retrieval grid: Q.ABS_SPECIES(2).GRIDS 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: www.sites.google.com/site/martinetpauline31
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