TABLE OF CONTENTS


MLT_RSS/AMSU_nadir.f90/amsu_simulated_tb [ Subroutines ]

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NAME

      amsu_simulated_tb

PURPOSE

      Calculates simulated AMSU Tb for a given channel, incidence angle, field of view, latitude, longitude and date.

INPUTS

               integer(4)                              :: chan    ! AMSU channel
               integer(4)                              :: fov     ! field of view index
               real(4)                                 :: theta   ! earth incidence angle (degrees)
               real(4)                                 :: lon     ! longitude
               real(4)                                 :: lat     ! latitude
               type(date_Str)                  :: date    ! date, in date structure form

OUTPUTS

       Error       Error Flag.  0 if everything OK, not zero otherwise

RETURNED VALUE

       climatological Tb value for the given parameters

USAGE

      Tb = amsu_simulated_tb(chan,fov,theta,lon,lat,date,error)

MLT_RSS/AMSU_nadir.f90/calculate_nadir_correction [ Subroutines ]

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NAME

      calculate_nadir_correction

PURPOSE

      Calculate nadir and incidence angle Corrections for a single AMSU scan line

INPUTS

      channel     AMSU channel number

INPUTS_OUTPUTS

      L2A_Scan    Structure containing AMSU L2A Scan data

OUTPUTS

      Error       Error Flag.  0 if everything OK, not zero otherwise

USAGE

      Call calculate_nadir_correction(L2A_scan,channel,error)

MLT_RSS/AMSU_nadir.f90/geometry [ Subroutines ]

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NAME

      geometry

PURPOSE

       calculates EIA tht for given nadir looking angle tht_nadir 

DESCRIPTION

       calculates EIA tht for given nadir looking angle tht_nadir
           at geodesic latitude xlat and height z above ground
               approximates the surface of the earth by a sphere with
           radius of curvature rho (c.f. RSS SSM/I Users Manual, DEC1, 1991)

INPUTS

               real(4)     tht_nadir   ! look angle
       real(4)     xlat        ! latitude of point on surface
       real(4)     z           ! height of satellite above surface

OUTPUTS

       real(4)     tht         ! earth incidence angle

USAGE

      call geometry (tht_nadir,xlat,z,tht)

MLT_RSS/AMSU_nadir.f90/read_amsu_tb_sim [ Subroutines ]

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NAME

      read_amsu_tb_sim

PURPOSE

      reads in climatological Tb data for a given channel and month and year

INPUTS

               integer(4)                                                              :: chan
               integer(4)                                                              :: month
               integer(4)                                                              :: year

OUTPUTS

       Error       Error Flag.  0 if everything OK, not zero otherwise

REMARKS

       loads climatological Tb value into module variable tb_sim

USAGE

      call read_amsu_tb_sim(chan,month,year,error)

MLT_RSS/AMSU_Nadir.f90 [ Methods ]

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NAME

    AMSU_Nadir.f90

PURPOSE

    Module for performing incidence angle adjustments to AMSU measurements

DESCRIPTION

    Module for performing incidence angle adjustments to AMSU measurements
    Uses a model derived fov and angle perturbation climatology for the calculations.
    The climatology is caclulated separately for each AMSU channel

AUTHOR

    Carl Mears, Remote Sensing Systems

COPYRIGHT

   THIS SOFTWARE AND ITS DOCUMENTATION ARE COPYRIGHT 2012 REMOTE SENSING SYSTEMS.  
   THEY ARE PROVIDED FOR INFORMATIONAL AND ALGORITHM VERIFICATION PURPOSES ONLY 
   AND MAY NOT BE USED IN WHOLE OR IN PART FOR ANY OTHER PURPOSE WITHOUT WRITTEN
   PERMISSION FROM REMOTE SENSING SYSTEMS.  THEY ARE FURNISHED "AS IS." THE 
   AUTHORS, THE UNITED STATES GOVERNMENT, ITS INSTRUMENTALITIES, OFFICERS, EMPLOYEES, 
   AND AGENTS MAKE NO WARRANTY, EXPRESS OR IMPLIED, AS TO THE USEFULNESS OF THE 
   SOFTWARE AND DOCUMENTATION FOR ANY PURPOSE. THEY ASSUME NO RESPONSIBILITY (1) FOR
   THE USE OF THE SOFTWARE AND DOCUMENTATION; OR (2) TO PROVIDE TECHNICAL SUPPORT 
   TO USERS.

HISTORY

    8/15/2012 Initial Version prepared for NCDC

USAGE

    use AMSU_Nadir