amsu_fov2za

 AMSU_FOV2ZA  Converts AMSU FOVs to zenith angles.

    Channel number can be 1 to 20.
    FOVs can be 0-14 for AMSU-A, and 0-44 for AMSU-B.

 FORMAT   za = amsu_fov2za( channel, fov )
        
 OUT   za        Zenith angle(s).
 IN    channel   Channel number (only one). 
       fov       Vector or matrix with FOV values.

0001 % AMSU_FOV2ZA  Converts AMSU FOVs to zenith angles.
0002 %
0003 %    Channel number can be 1 to 20.
0004 %    FOVs can be 0-14 for AMSU-A, and 0-44 for AMSU-B.
0005 %
0006 % FORMAT   za = amsu_fov2za( channel, fov )
0007 %
0008 % OUT   za        Zenith angle(s).
0009 % IN    channel   Channel number (only one).
0010 %       fov       Vector or matrix with FOV values.
0011 
0012 % 2004-04-07   Patrick Eriksson: Converted IDL function by Viju.
0013 
0014 
0015 function za = amsu_fov2za( channel, fov )
0016 %
0017 rqre_alltypes( channel, {@istensor0,@iswhole} );             %&%
0018 rqre_in_range( channel, 1, 20 );                             %&%
0019 
0020 
0021 if channel <= 15
0022   %                                                          %&%
0023   if any( fov < 0  |  fov > 14 )                             %&%
0024     error('For AMSU-A, FOV is 0 - 14.');                     %&%
0025   end                                                        %&%
0026   %
0027   za = 180 - ( 1.65 + (14-fov) * 3.3 );
0028 
0029 else
0030   %                                                          %&%
0031   if any( fov < 0  |  fov > 44 )                             %&%
0032     error('For AMSU-B, FOV is 0 - 44.');                     %&%
0033   end                                                        %&%
0034   %
0035   za = 180 - ( 0.55 + (44-fov) * 1.1 );
0036 
0037 end