Clarification on definitions/calculations in `rttov_wrf.py`

[CornelisSchwenk]

Hi,

First off, thank you so much for providing the code—it has been incredibly helpful! I have adapted the code to work with an ICON simulation instead of WRF. However, I have come across a few definitions/calculations in the rttov_wrf.py file where I have some questions. I would be very grateful if you could add some clarification:

Line 52:

surface_altitude = 0.49 # in kilometres

Surface altitude of what? The topography? Wouldn't that be a 2dim array specific for each lon-lat point?

Lines 56 to 57:

satzen = 45. # satellite zenith angle satazi = 180. # satellite azimuth angle

And Lines 177 to 182:

angles = np.array([[satzen, satazi, sunzen, sunazi]], dtype=np.float64) myProfiles.Angles = expand(nprofiles, angles)

surfgeom[3][nprofiles]: lat, lon, elev

surfgeom = np.array([[lat, lon, surface_altitude]], dtype=np.float64) myProfiles.SurfGeom = expand(nprofiles, surfgeom)

Same question, shouldn't these be calculated for every lon-lat point instead of being expanded and the same for every point?

Lines 161 to 166:

myProfiles.Stco = 0clw # Stratus Continental STCO myProfiles.Stma = 0clw # Stratus Maritime STMA myProfiles.Cucc = clw # Cumulus Continental Clean CUCC myProfiles.Cucp = 0clw # Cumulus Continental Polluted CUCP myProfiles.Cuma = 0clw # Cumulus Maritime CUMA myProfiles.Cirr = ciw # all ice clouds CIRR

What if I am looking over the ocean, would Stratus Maritime STMA then not be equal to zero? So zero where land and non-zero where ocean, and for STCO vice versa?

Line 171:

myProfiles.Icede = 60 * np.ones((nprofiles,nlevels)) # microns effective diameter

Are you assuming the effective diameter? If I have the number concentrations I could calculate this per grid cell instead, of assuming it for every cell, correct?

Thank you very much in advance!

Cornelis