Readme file for weighting function data files


This file
   afgl1to6_5ang_wf.mat
has weighting function for the 6 Air Force Geophysics Lab profiles
In order, these are:
   1=Tropical
   2=mid-latitude summer
   3=mid-latitude winter
   4=sub-polar summer
   5=sub-polar winter
   6=US Standard
The weighting functions are computed for 5 viewing
angles: 0,12,24,36,48 degrees.  So there is a total
of 30 weighting function.  The outer/slow index loop
is angle, the inner/fast index loop is profile.

Start up matlab and do the following
---
load afgl1to6_5ang_wf.mat
whos
---
This will load the file and show you what it contains.

To plot the weighting functions you can do something like
the following
---
for ic=1:2378
plot(squeeze(wf(:,ic,1))),title(int2str(ic))  
pause
end
---
This will loop over the 2378 channels and plot the weighting
function for each in turn (for the first profile at the first
angle). Hit any key to advance to the next channel.  The wf
has 100 layers, but the surface is at layer index 97 so the
wf in last 3 layers is always 0.  The layer mean altitude
can be computed as
---
zmean = 0.5*(altall(1:100,:) + altall(2:101,:));
pmean = 0.5*(prof.plevs(1:100,:) + prof.plevs(2:101,:));
---


See the matlab help for fopen, fclose and fwrite if
you want to write the data to simple binary files.
If would work something like this
---
fid = fopen('z.dat','w','native');
for ipa=1:30
fwrite(fid,zmean(1:100,ipa),'float32');
end
fclose(fid);
%
fid = fopen('wf.dat','w','native');
for ipa=1:30
for ic=1:2378
fwrite(fid,wf(1:100,ic,ipa),'float32');
end
end
fclose(fid);
---



This file
   afgl1to6_5ang_rad.mat
has the AFGL profiles.  Most of the data is in "prof". The
most useful items are:
   prof.scanang = angle
   prof.plat = latitude
   prof.rcalc = radiance
   prof.ptemp  = temperature
   prof.gas_1 = water vapor
   head.vchan = channel freqs


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