!
! CRTM_LowFrequency_MWSSEM
!
! Module containgin routines to compute microwave ocean emissivity components
! (FWD, TL, and AD) for low frequencies.
!
!
! CREATION HISTORY:
! Written by: Masahiro Kazumori, JCSDA 31-Jul-2006
! Masahiro.Kazumori@noaa.gov
! Quanhua Liu, QSS Group Inc.
! Quanhua.Liu@noaa.gov
!
! Refactored by: Paul van Delst, CIMSS/SSEC, April 2007
! paul.vandelst@ssec.wisc.edu
!
MODULE CRTM_LowFrequency_MWSSEM
! -----------------
! Environment setup
! -----------------
! Module use
USE Type_Kinds , ONLY: fp
USE Fresnel , ONLY: fVar_type => iVar_type , &
Fresnel_Reflectivity , &
Fresnel_Reflectivity_TL, &
Fresnel_Reflectivity_AD
USE Guillou , ONLY: gpVar_type => iVar_type, &
Guillou_Ocean_Permittivity , &
Guillou_Ocean_Permittivity_TL, &
Guillou_Ocean_Permittivity_AD
USE Ellison , ONLY: epVar_type => iVar_type, &
Ellison_Ocean_Permittivity , &
Ellison_Ocean_Permittivity_TL, &
Ellison_Ocean_Permittivity_AD
USE CRTM_Parameters , ONLY: PI, DEGREES_TO_RADIANS, &
ZERO, ONE, TWO, POINT_5
USE CRTM_Interpolation, ONLY: NPTS , &
LPoly_type , &
Clear_LPoly , &
Find_Index , &
LPoly , &
LPoly_TL , &
LPoly_AD , &
Interp_2D , &
Interp_2D_TL, &
Interp_2D_AD
! Disable implicit typing
IMPLICIT NONE
! ------------
! Visibilities
! ------------
! Everything private by default
PRIVATE
! Data types
PUBLIC :: iVar_type
! Science routines
PUBLIC :: LowFrequency_MWSSEM
PUBLIC :: LowFrequency_MWSSEM_TL
PUBLIC :: LowFrequency_MWSSEM_AD
! -----------------
! Module parameters
! -----------------
! RCS Id for the module
CHARACTER(*), PARAMETER :: MODULE_RCS_ID = &
'$Id: CRTM_LowFrequency_MWSSEM.f90 99117 2017-11-27 18:37:14Z tong.zhu@noaa.gov $'
! Various quantities
REAL(fp), PARAMETER :: LOW_F_THRESHOLD = 20.0_fp ! Frequency threshold for permittivity models(GHz)
REAL(fp), PARAMETER :: SMALLSCALE_F_THRESHOLD = 15.0_fp ! Frequency threshold for small scale limit(GHz)
REAL(fp), PARAMETER :: FOAM_THRESHOLD = 7.0_fp ! Wind speed threshold (m/s) for foam
REAL(fp), PARAMETER :: GHZ_TO_HZ = 1.0e+09_fp ! Frequency units conversion
! LUT dimension arrays
REAL(fp), PARAMETER :: D_FREQUENCY = 2.0_fp
INTEGER , PARAMETER :: N_FREQUENCIES = 11
REAL(fp), PARAMETER :: FREQUENCY_SDD(N_FREQUENCIES) = (/ &
3.0_fp, 5.0_fp, 7.0_fp, 9.0_fp, 11.0_fp, &
13.0_fp, 15.0_fp, 17.0_fp, 19.0_fp, 21.0_fp, &
23.0_fp /)
REAL(fp), PARAMETER :: D_WIND_SPEED = 0.5_fp
INTEGER , PARAMETER :: N_WIND_SPEEDS = 40
REAL(fp), PARAMETER :: WIND_SPEED_SDD(N_WIND_SPEEDS) = (/ &
0.5_fp, 1.0_fp, 1.5_fp, 2.0_fp, 2.5_fp, 3.0_fp, 3.5_fp, 4.0_fp, &
4.5_fp, 5.0_fp, 5.5_fp, 6.0_fp, 6.5_fp, 7.0_fp, 7.5_fp, 8.0_fp, &
8.5_fp, 9.0_fp, 9.5_fp,10.0_fp,10.5_fp,11.0_fp,11.5_fp,12.0_fp, &
12.5_fp,13.0_fp,13.5_fp,14.0_fp,14.5_fp,15.0_fp,15.5_fp,16.0_fp, &
16.5_fp,17.0_fp,17.5_fp,18.0_fp,18.5_fp,19.0_fp,19.5_fp,20.0_fp /)
! Foam coverage coefficients
! See Eqn.(1) in
! Liu, Q. et al. (1998) Monte Carlo simulations of the
! microwave emissivity of the sea surface.
! JGR, Volume 103, No.C11, Pages 24983-24989
REAL(fp), PARAMETER :: FC1 = 7.751e-6_fp ! FWD model
REAL(fp), PARAMETER :: FC2 = 3.231_fp ! FWD model
REAL(fp), PARAMETER :: FC3 = FC1*FC2 ! TL model
REAL(fp), PARAMETER :: FC4 = FC2-ONE ! TL model
! Reflectivity large scale correction coefficients
REAL(fp), PARAMETER :: LSC_COEFF(8) = &
(/ 5.209e-04_fp, 1.582e-05_fp, -3.510e-07_fp, & ! Rv coefficients
5.209e-04_fp, -1.550e-05_fp, -1.356e-07_fp, & ! Rh coefficients
1.90896_fp, 0.120448_fp /) ! Frequency coefficients
! --------------------------------------
! Structure definition to hold internal
! variables across FWD, TL, and AD calls
! --------------------------------------
TYPE :: iVar_type
PRIVATE
! Validity indicator
LOGICAL :: Is_Valid = .FALSE.
! Forward model input values
REAL(fp) :: Frequency = ZERO
REAL(fp) :: Zenith_Angle = ZERO
REAL(fp) :: Temperature = ZERO
REAL(fp) :: Salinity = ZERO
REAL(fp) :: Wind_Speed = ZERO
! The zenith angle terms
REAL(fp) :: cos_z = ZERO, cos2_z = ZERO
! The interpolating polynomials
TYPE(LPoly_type) :: flp ! Frequency
TYPE(LPoly_type) :: wlp ! Wind speed
! The LUT interpolation indices
INTEGER :: i1 = -1, i2 = -1 ! Frequency
INTEGER :: j1 = -1, j2 = -1 ! Wind speed
! The interpolation input
REAL(fp) :: f_int = ZERO ! Frequency
REAL(fp) :: w_int = ZERO ! Wind speed
! The interpolation output
REAL(fp) :: sdd_int = ZERO ! Ocean surface height variance
! Ocean permittivity
COMPLEX(fp) :: Permittivity = ZERO
! Fresnel reflectivties
REAL(fp) :: Rv_Fresnel = ZERO
REAL(fp) :: Rh_Fresnel = ZERO
! Foam reflectivties
REAL(fp) :: Rv_Foam = ZERO
REAL(fp) :: Rh_Foam = ZERO
! Foam coverage
REAL(fp) :: Foam_Cover = ZERO
! Small scale correction intermediate term
REAL(fp) :: R_STerm = ZERO
! Small scale correction to reflectivities
REAL(fp) :: Rv_Small = ZERO
REAL(fp) :: Rh_Small = ZERO
! Large scale correction intermediate terms
REAL(fp) :: Rv_LTerm = ZERO
REAL(fp) :: Rh_LTerm = ZERO
! Final reflectivity
REAL(fp) :: Rv = ZERO
REAL(fp) :: Rh = ZERO
! Internal variables for subcomponents
TYPE(fVar_type) :: fVar
TYPE(epVar_type) :: epVar
TYPE(gpVar_type) :: gpVar
END TYPE iVar_type
! -----------------------------------------------------
! LUT data. Ocean surface height variance. Units of m^2
! -----------------------------------------------------
REAL(fp) :: sdd(N_FREQUENCIES,N_WIND_SPEEDS)
INTEGER :: n
DATA (sdd(n,1),n=1,N_FREQUENCIES) / &
3.45700E-03_fp, 9.60280E-03_fp, 1.86610E-02_fp, 2.63970E-02_fp, 2.99600E-02_fp, &
3.11630E-02_fp, 3.11300E-02_fp, 3.02250E-02_fp, 2.87810E-02_fp, 2.73210E-02_fp, &
2.57200E-02_fp /
DATA (sdd(n,2),n=1,N_FREQUENCIES) / &
4.04780E-02_fp, 4.26570E-02_fp, 4.30630E-02_fp, 4.22650E-02_fp, 4.07540E-02_fp, &
3.94740E-02_fp, 3.78900E-02_fp, 3.60050E-02_fp, 3.41810E-02_fp, 3.24220E-02_fp, &
3.04150E-02_fp /
DATA (sdd(n,3),n=1,N_FREQUENCIES) / &
4.59590E-02_fp, 4.48090E-02_fp, 4.46420E-02_fp, 4.36330E-02_fp, 4.24890E-02_fp, &
4.15140E-02_fp, 4.01950E-02_fp, 3.88670E-02_fp, 3.74780E-02_fp, 3.60030E-02_fp, &
3.53260E-02_fp /
DATA (sdd(n,4),n=1,N_FREQUENCIES) / &
4.59450E-02_fp, 4.58550E-02_fp, 4.47040E-02_fp, 4.46270E-02_fp, 4.41120E-02_fp, &
4.32700E-02_fp, 4.28010E-02_fp, 4.19510E-02_fp, 4.10440E-02_fp, 4.08170E-02_fp, &
4.11710E-02_fp /
DATA (sdd(n,5),n=1,N_FREQUENCIES) / &
4.64550E-02_fp, 4.56360E-02_fp, 4.59130E-02_fp, 4.55520E-02_fp, 4.53160E-02_fp, &
4.51440E-02_fp, 4.53070E-02_fp, 4.51610E-02_fp, 4.52720E-02_fp, 4.59090E-02_fp, &
4.67220E-02_fp /
DATA (sdd(n,6),n=1,N_FREQUENCIES) / &
4.66200E-02_fp, 4.59520E-02_fp, 4.58590E-02_fp, 4.60200E-02_fp, 4.59480E-02_fp, &
4.64690E-02_fp, 4.65140E-02_fp, 4.70470E-02_fp, 4.72740E-02_fp, 4.85060E-02_fp, &
4.90510E-02_fp /
DATA (sdd(n,7),n=1,N_FREQUENCIES) / &
4.61430E-02_fp, 4.62460E-02_fp, 4.63810E-02_fp, 4.67430E-02_fp, 4.77040E-02_fp, &
4.85840E-02_fp, 4.95640E-02_fp, 5.12130E-02_fp, 5.25020E-02_fp, 5.29830E-02_fp, &
5.38460E-02_fp /
DATA (sdd(n,8),n=1,N_FREQUENCIES) / &
4.66920E-02_fp, 4.60310E-02_fp, 4.66870E-02_fp, 4.77130E-02_fp, 4.86120E-02_fp, &
4.99180E-02_fp, 5.17960E-02_fp, 5.37230E-02_fp, 5.46800E-02_fp, 5.54400E-02_fp, &
5.60010E-02_fp /
DATA (sdd(n,9),n=1,N_FREQUENCIES) / &
4.63630E-02_fp, 4.69850E-02_fp, 4.79640E-02_fp, 4.94210E-02_fp, 5.30620E-02_fp, &
5.50180E-02_fp, 5.59020E-02_fp, 5.75140E-02_fp, 5.88560E-02_fp, 5.99310E-02_fp, &
6.00960E-02_fp /
DATA (sdd(n,10),n=1,N_FREQUENCIES) / &
4.65880E-02_fp, 4.71020E-02_fp, 4.87240E-02_fp, 5.08410E-02_fp, 5.46400E-02_fp, &
5.65520E-02_fp, 5.82880E-02_fp, 5.97860E-02_fp, 6.10270E-02_fp, 6.20060E-02_fp, &
6.20490E-02_fp /
DATA (sdd(n,11),n=1,N_FREQUENCIES) / &
4.63770E-02_fp, 4.79790E-02_fp, 5.07890E-02_fp, 5.49620E-02_fp, 5.83330E-02_fp, &
6.02050E-02_fp, 6.19130E-02_fp, 6.33790E-02_fp, 6.45780E-02_fp, 6.55040E-02_fp, &
6.61630E-02_fp /
DATA (sdd(n,12),n=1,N_FREQUENCIES) / &
4.66490E-02_fp, 4.87630E-02_fp, 5.48840E-02_fp, 5.66550E-02_fp, 6.01050E-02_fp, &
6.20090E-02_fp, 6.37430E-02_fp, 6.52270E-02_fp, 6.64330E-02_fp, 6.73580E-02_fp, &
6.80090E-02_fp /
DATA (sdd(n,13),n=1,N_FREQUENCIES) / &
4.73370E-02_fp, 5.04070E-02_fp, 5.78990E-02_fp, 5.98650E-02_fp, 6.35580E-02_fp, &
6.55950E-02_fp, 6.74360E-02_fp, 6.90000E-02_fp, 7.02620E-02_fp, 7.12200E-02_fp, &
7.18850E-02_fp /
DATA (sdd(n,14),n=1,N_FREQUENCIES) / &
4.79880E-02_fp, 5.43970E-02_fp, 6.08900E-02_fp, 6.31260E-02_fp, 6.56630E-02_fp, &
6.93250E-02_fp, 7.01740E-02_fp, 7.19480E-02_fp, 7.33710E-02_fp, 7.44530E-02_fp, &
7.52120E-02_fp /
DATA (sdd(n,15),n=1,N_FREQUENCIES) / &
4.88910E-02_fp, 5.87050E-02_fp, 6.30810E-02_fp, 6.58100E-02_fp, 6.87010E-02_fp, &
7.13730E-02_fp, 7.37010E-02_fp, 7.56450E-02_fp, 7.72040E-02_fp, 7.83900E-02_fp, &
7.83620E-02_fp /
DATA (sdd(n,16),n=1,N_FREQUENCIES) / &
5.08950E-02_fp, 6.31620E-02_fp, 6.58390E-02_fp, 7.13070E-02_fp, 7.45450E-02_fp, &
7.61300E-02_fp, 7.88420E-02_fp, 7.99710E-02_fp, 8.18550E-02_fp, 8.23400E-02_fp, &
8.34470E-02_fp /
DATA (sdd(n,17),n=1,N_FREQUENCIES) / &
5.54760E-02_fp, 6.46340E-02_fp, 6.81130E-02_fp, 7.41470E-02_fp, 7.61420E-02_fp, &
7.96030E-02_fp, 8.12890E-02_fp, 8.38430E-02_fp, 8.48200E-02_fp, 8.54770E-02_fp, &
8.67520E-02_fp /
DATA (sdd(n,18),n=1,N_FREQUENCIES) / &
5.87440E-02_fp, 6.91110E-02_fp, 7.31410E-02_fp, 7.77400E-02_fp, 8.03610E-02_fp, &
8.28910E-02_fp, 8.64080E-02_fp, 8.81030E-02_fp, 8.94090E-02_fp, 9.03320E-02_fp, &
9.08970E-02_fp /
DATA (sdd(n,19),n=1,N_FREQUENCIES) / &
6.37450E-02_fp, 7.11440E-02_fp, 7.64340E-02_fp, 8.18560E-02_fp, 8.50240E-02_fp, &
8.79790E-02_fp, 9.05320E-02_fp, 9.26230E-02_fp, 9.31090E-02_fp, 9.43720E-02_fp, &
9.52240E-02_fp /
DATA (sdd(n,20),n=1,N_FREQUENCIES) / &
6.75330E-02_fp, 7.14800E-02_fp, 7.78540E-02_fp, 8.39610E-02_fp, 8.75990E-02_fp, &
9.09100E-02_fp, 9.23600E-02_fp, 9.47960E-02_fp, 9.67050E-02_fp, 9.70420E-02_fp, &
9.80910E-02_fp /
DATA (sdd(n,21),n=1,N_FREQUENCIES) / &
6.83640E-02_fp, 7.42600E-02_fp, 8.16470E-02_fp, 8.63360E-02_fp, 9.07880E-02_fp, &
9.47130E-02_fp, 9.66050E-02_fp, 9.94340E-02_fp, 1.00460E-01_fp, 1.01120E-01_fp, &
1.02470E-01_fp /
DATA (sdd(n,22),n=1,N_FREQUENCIES) / &
7.34960E-02_fp, 7.95300E-02_fp, 8.45850E-02_fp, 9.00820E-02_fp, 9.51380E-02_fp, &
9.79040E-02_fp, 1.00300E-01_fp, 1.02240E-01_fp, 1.04930E-01_fp, 1.05860E-01_fp, &
1.06410E-01_fp /
DATA (sdd(n,23),n=1,N_FREQUENCIES) / &
7.10970E-02_fp, 8.02870E-02_fp, 8.95720E-02_fp, 9.32400E-02_fp, 9.89780E-02_fp, &
1.02230E-01_fp, 1.03530E-01_fp, 1.05910E-01_fp, 1.07750E-01_fp, 1.09070E-01_fp, &
1.09960E-01_fp /
DATA (sdd(n,24),n=1,N_FREQUENCIES) / &
7.36820E-02_fp, 8.40180E-02_fp, 9.12120E-02_fp, 9.81670E-02_fp, 1.02370E-01_fp, &
1.04470E-01_fp, 1.07850E-01_fp, 1.10580E-01_fp, 1.11430E-01_fp, 1.13090E-01_fp, &
1.14270E-01_fp /
DATA (sdd(n,25),n=1,N_FREQUENCIES) / &
8.18210E-02_fp, 8.72020E-02_fp, 9.52010E-02_fp, 1.00400E-01_fp, 1.05370E-01_fp, &
1.08020E-01_fp, 1.11860E-01_fp, 1.13550E-01_fp, 1.16100E-01_fp, 1.16820E-01_fp, &
1.18310E-01_fp /
DATA (sdd(n,26),n=1,N_FREQUENCIES) / &
8.28020E-02_fp, 8.99060E-02_fp, 9.88250E-02_fp, 1.02260E-01_fp, 1.08030E-01_fp, &
1.11260E-01_fp, 1.15580E-01_fp, 1.17650E-01_fp, 1.19200E-01_fp, 1.20280E-01_fp, &
1.22110E-01_fp /
DATA (sdd(n,27),n=1,N_FREQUENCIES) / &
8.31730E-02_fp, 9.21910E-02_fp, 9.91400E-02_fp, 1.06140E-01_fp, 1.10390E-01_fp, &
1.16000E-01_fp, 1.17460E-01_fp, 1.20050E-01_fp, 1.22050E-01_fp, 1.23510E-01_fp, &
1.25680E-01_fp /
DATA (sdd(n,28),n=1,N_FREQUENCIES) / &
8.30700E-02_fp, 9.41130E-02_fp, 1.02090E-01_fp, 1.09790E-01_fp, 1.14520E-01_fp, &
1.18740E-01_fp, 1.22290E-01_fp, 1.23670E-01_fp, 1.26010E-01_fp, 1.27770E-01_fp, &
1.29050E-01_fp /
DATA (sdd(n,29),n=1,N_FREQUENCIES) / &
8.91170E-02_fp, 9.98440E-02_fp, 1.04780E-01_fp, 1.13210E-01_fp, 1.16370E-01_fp, &
1.21240E-01_fp, 1.25310E-01_fp, 1.27100E-01_fp, 1.29790E-01_fp, 1.30580E-01_fp, &
1.32220E-01_fp /
DATA (sdd(n,30),n=1,N_FREQUENCIES) / &
8.81060E-02_fp, 1.01160E-01_fp, 1.07230E-01_fp, 1.13940E-01_fp, 1.20090E-01_fp, &
1.25390E-01_fp, 1.28140E-01_fp, 1.30340E-01_fp, 1.33410E-01_fp, 1.34500E-01_fp, &
1.35220E-01_fp /
DATA (sdd(n,31),n=1,N_FREQUENCIES) / &
9.35810E-02_fp, 1.02220E-01_fp, 1.12600E-01_fp, 1.16940E-01_fp, 1.23650E-01_fp, &
1.27510E-01_fp, 1.30780E-01_fp, 1.33410E-01_fp, 1.35440E-01_fp, 1.38270E-01_fp, &
1.39280E-01_fp /
DATA (sdd(n,32),n=1,N_FREQUENCIES) / &
9.35500E-02_fp, 1.04710E-01_fp, 1.13220E-01_fp, 1.21530E-01_fp, 1.26710E-01_fp, &
1.31310E-01_fp, 1.35180E-01_fp, 1.38300E-01_fp, 1.40760E-01_fp, 1.41310E-01_fp, &
1.42850E-01_fp /
DATA (sdd(n,33),n=1,N_FREQUENCIES) / &
9.85130E-02_fp, 1.09590E-01_fp, 1.18240E-01_fp, 1.24170E-01_fp, 1.29910E-01_fp, &
1.34960E-01_fp, 1.37450E-01_fp, 1.41030E-01_fp, 1.43870E-01_fp, 1.44760E-01_fp, &
1.46610E-01_fp /
DATA (sdd(n,34),n=1,N_FREQUENCIES) / &
9.61960E-02_fp, 1.09960E-01_fp, 1.19920E-01_fp, 1.26660E-01_fp, 1.32990E-01_fp, &
1.36530E-01_fp, 1.41320E-01_fp, 1.43620E-01_fp, 1.46860E-01_fp, 1.48090E-01_fp, &
1.50270E-01_fp /
DATA (sdd(n,35),n=1,N_FREQUENCIES) / &
1.00720E-01_fp, 1.14610E-01_fp, 1.21450E-01_fp, 1.29020E-01_fp, 1.35940E-01_fp, &
1.39920E-01_fp, 1.43320E-01_fp, 1.47690E-01_fp, 1.49730E-01_fp, 1.51310E-01_fp, &
1.52550E-01_fp /
DATA (sdd(n,36),n=1,N_FREQUENCIES) / &
1.06720E-01_fp, 1.16120E-01_fp, 1.24380E-01_fp, 1.32860E-01_fp, 1.38180E-01_fp, &
1.44960E-01_fp, 1.48770E-01_fp, 1.50260E-01_fp, 1.52880E-01_fp, 1.54980E-01_fp, &
1.56700E-01_fp /
DATA (sdd(n,37),n=1,N_FREQUENCIES) / &
1.03610E-01_fp, 1.15990E-01_fp, 1.28950E-01_fp, 1.34940E-01_fp, 1.40860E-01_fp, &
1.46100E-01_fp, 1.50500E-01_fp, 1.54100E-01_fp, 1.57010E-01_fp, 1.57970E-01_fp, &
1.60030E-01_fp /
DATA (sdd(n,38),n=1,N_FREQUENCIES) / &
1.09100E-01_fp, 1.21630E-01_fp, 1.31540E-01_fp, 1.38450E-01_fp, 1.45050E-01_fp, &
1.50820E-01_fp, 1.53830E-01_fp, 1.57980E-01_fp, 1.59840E-01_fp, 1.62740E-01_fp, &
1.63900E-01_fp /
DATA (sdd(n,39),n=1,N_FREQUENCIES) / &
1.13210E-01_fp, 1.21190E-01_fp, 1.32510E-01_fp, 1.40300E-01_fp, 1.47510E-01_fp, &
1.53760E-01_fp, 1.57150E-01_fp, 1.59950E-01_fp, 1.63770E-01_fp, 1.65520E-01_fp, &
1.67040E-01_fp /
DATA (sdd(n,40),n=1,N_FREQUENCIES) / &
1.06990E-01_fp, 1.22540E-01_fp, 1.33950E-01_fp, 1.41810E-01_fp, 1.49100E-01_fp, &
1.53340E-01_fp, 1.58850E-01_fp, 1.61700E-01_fp, 1.64030E-01_fp, 1.65960E-01_fp, &
1.68950E-01_fp /
CONTAINS
!################################################################################
!################################################################################
!## ##
!## ## PUBLIC MODULE ROUTINES ## ##
!## ##
!################################################################################
!################################################################################
!--------------------------------------------------------------------------------
!
! NAME:
! LowFrequency_MWSSEM
!
! PURPOSE:
! Subroutine to compute microwave sea surface emissivity for the
! frequency range 5GHz < f < 20GHz
!
! CALLING SEQUENCE:
! CALL LowFrequency_MWSSEM( &
! Frequency , & ! Input
! Zenith_Angle, & ! Input
! Temperature , & ! Input
! Salinity , & ! Input
! Wind_Speed , & ! Input
! Emissivity , & ! Output
! iVar ) ! Internal variable output
!
! INPUT ARGUMENTS:
! Frequency: Microwave frequency. Valid input range is
! UNITS: GHz
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Zenith_Angle: Satellite zenith angle at the
! sea surface
! UNITS: Degrees
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Temperature: Sea surface temperature
! UNITS: Kelvin, K
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Salinity: Water salinity
! UNITS: ppt (parts per thousand)
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Wind_Speed: Sea surface wind speed
! UNITS: m/s
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! OUTPUT ARGUMENTS:
! Emissivity: The surface emissivity at vertical
! and horizontal polarizations.
! UNITS: N/A
! TYPE: REAL(fp)
! DIMENSION: Rank-1
! ATTRIBUTES: INTENT(OUT)
!
! iVar: Structure containing internal variables required for
! subsequent tangent-linear or adjoint model calls.
! The contents of this structure are NOT accessible
! outside of this module.
! UNITS: N/A
! TYPE: iVar_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(OUT)
!
! COMMENTS:
! For computational speed, no input checking is done.
! - Valid frequency range is 5GHz < f < 20GHz
! - The size of the output emissivity array is not checked on input.
! It is assumed the caller has dimensioned it correctly.
!
!--------------------------------------------------------------------------------
SUBROUTINE LowFrequency_MWSSEM( Frequency , & ! Input
Zenith_Angle, & ! Input
Temperature , & ! Input
Salinity , & ! Input
Wind_Speed , & ! Input
Emissivity , & ! Output
iVar ) ! Internal variable output
! Arguments
REAL(fp), INTENT(IN) :: Frequency
REAL(fp), INTENT(IN) :: Zenith_Angle
REAL(fp), INTENT(IN) :: Temperature
REAL(fp), INTENT(IN) :: Salinity
REAL(fp), INTENT(IN) :: Wind_Speed
REAL(fp), INTENT(OUT) :: Emissivity(:)
TYPE(iVar_type), INTENT(IN OUT) :: iVar
! Local variables
LOGICAL :: f_outbound, w_outbound
REAL(fp) :: Rv_Large, Rh_Large
! Setup
! ...Save forward input variables for TL and AD calculations
iVar%Frequency = Frequency
iVar%Zenith_Angle = Zenith_Angle
iVar%Temperature = Temperature
iVar%Salinity = Salinity
iVar%Wind_Speed = Wind_Speed
! ...Save derived variables
iVar%cos_z = COS(Zenith_Angle*DEGREES_TO_RADIANS)
iVar%cos2_z = iVar%cos_z * iVar%cos_z
! Find the wind speed and frequency indices for interpolation
iVar%f_int = MAX(MIN(FREQUENCY_SDD(N_FREQUENCIES),Frequency),FREQUENCY_SDD(1))
CALL Find_Index(FREQUENCY_SDD, D_FREQUENCY, iVar%f_int, iVar%i1, iVar%i2, f_outbound)
iVar%w_int = MAX(MIN(WIND_SPEED_SDD(N_WIND_SPEEDS),Wind_Speed),WIND_SPEED_SDD(1))
CALL Find_Index(WIND_SPEED_SDD, D_WIND_SPEED, iVar%w_int, iVar%j1, iVar%j2, w_outbound)
! Calculate the interpolating polynomials
! ...Frequency term
CALL LPoly( FREQUENCY_SDD(iVar%i1:iVar%i2), & ! Input
iVar%f_int , & ! Input
iVar%flp ) ! Output
! ...Wind speed term
CALL LPoly( WIND_SPEED_SDD(iVar%j1:iVar%j2), & ! Input
iVar%w_int , & ! Input
iVar%wlp ) ! Output
! Perform the 2-D interpolation
CALL Interp_2D( sdd(iVar%i1:iVar%i2, iVar%j1:iVar%j2), &
iVar%flp, iVar%wlp, iVar%sdd_int )
! Permittivity Calculation
IF( Frequency < LOW_F_THRESHOLD ) THEN
CALL Guillou_Ocean_Permittivity( Temperature, Salinity, Frequency, &
iVar%Permittivity, &
iVar%gpVar )
ELSE
CALL Ellison_Ocean_Permittivity( Temperature, Frequency, &
iVar%Permittivity, &
iVar%epVar )
END IF
! Fresnel reflectivity calculation
CALL Fresnel_Reflectivity( iVar%Permittivity,iVar%cos_z, &
iVar%Rv_Fresnel,iVar%Rh_Fresnel,&
iVar%fVar )
! Foam reflectivity calculation
CALL Foam_Reflectivity( Zenith_Angle, iVar%Rv_Foam, iVar%Rh_Foam )
! Foam Coverage calculation
CALL Foam_Coverage( Wind_Speed, iVar%Foam_Cover )
! Small scale correction calculation
CALL Small_Scale_Correction( iVar%sdd_int, iVar%cos2_z, Frequency, &
iVar%Rv_Small, iVar%Rh_Small, &
iVar%R_STerm )
iVar%Rv = iVar%Rv_Fresnel * iVar%Rv_Small
iVar%Rh = iVar%Rh_Fresnel * iVar%Rh_Small
! Large Scale Correction Calculation
CALL Large_Scale_Correction( Wind_Speed, Zenith_Angle, Frequency, &
Rv_Large, Rh_Large, &
iVar%Rv_Lterm, iVar%Rh_Lterm )
iVar%Rv = iVar%Rv + Rv_Large
iVar%Rh = iVar%Rh + Rh_Large
! Emissivity Calculation
Emissivity(1) = ONE - (ONE-iVar%Foam_Cover)*iVar%Rv - iVar%Foam_Cover*iVar%Rv_Foam
Emissivity(2) = ONE - (ONE-iVar%Foam_Cover)*iVar%Rh - iVar%Foam_Cover*iVar%Rh_Foam
! Flag the internal variable structure as valid
iVar%Is_Valid = .TRUE.
END SUBROUTINE LowFrequency_MWSSEM
!--------------------------------------------------------------------------------
!
! NAME:
! LowFrequency_MWSSEM_TL
!
! PURPOSE:
! Subroutine to compute the tangent-linear microwave sea surface
! emissivity for the frequency range 5GHz < f < 20GHz
!
! CALLING SEQUENCE:
! CALL LowFrequency_MWSSEM_TL( &
! Temperature_TL, & ! TL Input
! Salinity_TL , & ! TL Input
! Wind_Speed_TL , & ! TL Input
! Emissivity_TL , & ! TL Output
! iVar ) ! Internal variable input
!
! INPUT ARGUMENTS:
! Temperature_TL: The tangent-linear sea surface temperature
! UNITS: Kelvin, K
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Salinity_TL: The tangent-linear water salinity
! UNITS: ppt (parts per thousand)
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Wind_Speed_TL: The tangent-linear sea surface wind speed
! UNITS: m/s
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! iVar: Structure containing internal forward variables
! required for tangent-linear calculations. This
! structure is output from the forward model.
! The contents of this structure are NOT accessible
! outside of this module.
! UNITS: N/A
! TYPE: iVar_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! OUTPUT ARGUMENTS:
! Emissivity_TL: The tangent-linear sea surface emissivity at
! vertical and horizontal polarizations.
! UNITS: N/A
! TYPE: REAL(fp)
! DIMENSION: Rank-1
! ATTRIBUTES: INTENT(OUT)
!
! COMMENTS:
! For computational speed, no input checking is done.
! - Valid frequency range is 5GHz < f < 20GHz
! - The size of the output emissivity array is not checked on input.
! It is assumed the caller has dimensioned it correctly.
!
!--------------------------------------------------------------------------------
SUBROUTINE LowFrequency_MWSSEM_TL( &
Temperature_TL, & ! TL Input
Salinity_TL , & ! TL Input
Wind_Speed_TL , & ! TL Input
Emissivity_TL , & ! TL Output
iVar ) ! Internal variable input
! Arguments
REAL(fp), INTENT(IN) :: Temperature_TL
REAL(fp), INTENT(IN) :: Salinity_TL
REAL(fp), INTENT(IN) :: Wind_Speed_TL
REAL(fp), INTENT(OUT) :: Emissivity_TL(:)
TYPE(iVar_type), INTENT(IN) :: iVar
! Local variables
REAL(fp) :: sdd_int_TL
COMPLEX(fp) :: Permittivity_TL
REAL(fp) :: Foam_Cover_TL
REAL(fp) :: Rv_Fresnel_TL, Rh_Fresnel_TL
REAL(fp) :: Rv_Foam_TL , Rh_Foam_TL
REAL(fp) :: Rv_Small_TL , Rh_Small_TL
REAL(fp) :: Rv_Large_TL , Rh_Large_TL
REAL(fp) :: Rv_TL , Rh_TL
REAL(fp) :: w_int_TL
REAL(fp), DIMENSION(NPTS) :: w_TL
REAL(fp), DIMENSION(NPTS,NPTS) :: sdd_TL
TYPE(LPoly_type) :: flp_TL, wlp_TL
! Setup
! ...Check internal structure
IF ( .NOT. iVar%Is_Valid ) THEN
Emissivity_TL = ZERO
RETURN
END IF
! ...Initialise local TL variables
w_int_TL = Wind_Speed_TL
w_TL = ZERO
sdd_TL = ZERO
! Calculate the TL interpolating polynomials
! ...Frequency term.
! The TL frequency term is always zero (so far at least)
! so we just need to initialise the polynomial so it has
! no impact on the TL interpolation below.
CALL Clear_LPoly(flp_TL)
! Wind speed term
CALL LPoly_TL( WIND_SPEED_SDD(iVar%j1:iVar%j2), & ! FWD Input
iVar%w_int , & ! FWD Input
iVar%wlp , & ! FWD Input
w_TL , & ! TL Input
w_int_TL , & ! TL Input
wlp_TL ) ! TL Output
! Perform the 2-D TL interpolation
CALL Interp_2D_TL( sdd(iVar%i1:iVar%i2, iVar%j1:iVar%j2), & ! FWD Input
iVar%flp, iVar%wlp, & ! FWD Input
sdd_TL, & ! TL Input
flp_TL , wlp_TL, & ! TL Input
sdd_int_TL ) ! TL Output
! Permittivity Calculation
IF( iVar%Frequency < LOW_F_THRESHOLD ) THEN
CALL Guillou_Ocean_Permittivity_TL( Temperature_TL, Salinity_TL, iVar%Frequency, &
Permittivity_TL, &
iVar%gpVar)
ELSE
CALL Ellison_Ocean_Permittivity_TL( Temperature_TL, &
Permittivity_TL, &
iVar%epVar )
END IF
! Fresnel reflectivity calculation
CALL Fresnel_Reflectivity_TL( Permittivity_TL, iVar%cos_z, &
Rv_Fresnel_TL, Rh_Fresnel_TL, &
iVar%fVar )
! Foam reflectivity "calculation"
Rv_Foam_TL = ZERO
Rh_Foam_TL = ZERO
! Foam coverage calculation
CALL Foam_Coverage_TL( iVar%Wind_Speed, Wind_Speed_TL, Foam_Cover_TL )
! Small scale correction calculation
CALL Small_Scale_Correction_TL( sdd_int_TL, iVar%cos2_z, iVar%Frequency, &
Rv_Small_TL, Rh_Small_TL, &
iVar%R_STerm )
Rv_TL = iVar%Rv_Fresnel*Rv_Small_TL + Rv_Fresnel_TL*iVar%Rv_Small
Rh_TL = iVar%Rh_Fresnel*Rh_Small_TL + Rh_Fresnel_TL*iVar%Rh_Small
! Large scale correction calculation
CALL Large_Scale_Correction_TL( Wind_Speed_TL, Rv_Large_TL, Rh_Large_TL, &
iVar%Rv_Lterm, iVar%Rh_Lterm )
Rv_TL = Rv_TL + Rv_Large_TL
Rh_TL = Rh_TL + Rh_Large_TL
! Emissivity calculation
Emissivity_TL(1) = (iVar%Foam_Cover-ONE)*Rv_TL + &
(iVar%Rv-iVar%Rv_Foam)*Foam_Cover_TL - &
iVar%Foam_Cover*Rv_Foam_TL
Emissivity_TL(2) = (iVar%Foam_Cover-ONE)*Rh_TL + &
(iVar%Rh-iVar%Rh_Foam)*Foam_Cover_TL - &
iVar%Foam_Cover*Rh_Foam_TL
END SUBROUTINE LowFrequency_MWSSEM_TL
!--------------------------------------------------------------------------------
!
! NAME:
! LowFrequency_MWSSEM_AD
!
! PURPOSE:
! Subroutine to compute the adjoint microwave sea surface emissivity
! for the frequency range 5GHz < f < 20GHz
!
! CALLING SEQUENCE:
! CALL LowFrequency_MWSSEM_AD( &
! Emissivity_AD , & ! AD Input
! Temperature_AD, & ! AD Output
! Salinity_AD , & ! AD Output
! Wind_Speed_AD , & ! AD Output
! iVar ) ! Internal variable input
!
! INPUT ARGUMENTS:
! Emissivity_AD: The adjoint sea surface emissivity at
! vertical and horizontal polarizations.
! UNITS: N/A
! TYPE: REAL(fp)
! DIMENSION: Rank-1
! ATTRIBUTES: INTENT(IN OUT)
!
! iVar: Structure containing internal forward variables
! required for adjoint calculations. This
! structure is output from the forward model.
! The contents of this structure are NOT accessible
! outside of this module.
! UNITS: N/A
! TYPE: iVar_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! OUTPUT ARGUMENTS:
! Temperature_AD: The adjoint sea surface temperature
! UNITS: (Kelvin, K)^-1
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Salinity_AD: The adjoint water salinity
! UNITS: (ppt)^-1
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Wind_Speed_AD: The adjoint sea surface wind speed
! UNITS: (m/s)^-1
! TYPE: REAL(fp)
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! SIDE EFFECTS:
! The input adjoint variable, Emissivity_AD, is set to zero upon
! exiting this routine.
!
! COMMENTS:
! For computational speed, no input checking is done.
! - Valid frequency range is 5GHz < f < 20GHz
! - The size of the input emissivity array is not checked on input.
! It is assumed the caller has dimensioned it correctly.
!
!--------------------------------------------------------------------------------
SUBROUTINE LowFrequency_MWSSEM_AD( &
Emissivity_AD , & ! AD Input
Temperature_AD, & ! AD Output
Salinity_AD , & ! AD Output
Wind_Speed_AD , & ! AD Output
iVar ) ! Internal variable input
! Arguments
REAL(fp), INTENT(IN OUT) :: Emissivity_AD(:)
REAL(fp), INTENT(IN OUT) :: Temperature_AD
REAL(fp), INTENT(IN OUT) :: Salinity_AD
REAL(fp), INTENT(IN OUT) :: Wind_Speed_AD
TYPE(iVar_type), INTENT(IN) :: iVar
! Local variables
REAL(fp) :: sdd_int_AD
COMPLEX(fp) :: Permittivity_AD
REAL(fp) :: Foam_Cover_AD
REAL(fp) :: Rv_Fresnel_AD, Rh_Fresnel_AD
REAL(fp) :: Rv_Foam_AD , Rh_Foam_AD
REAL(fp) :: Rv_Small_AD , Rh_Small_AD
REAL(fp) :: Rv_Large_AD , Rh_Large_AD
REAL(fp) :: Rv_AD , Rh_AD
REAL(fp) :: w_int_AD
REAL(fp), DIMENSION(NPTS) :: w_AD
REAL(fp), DIMENSION(NPTS,NPTS) :: sdd_AD
TYPE(LPoly_type) :: flp_AD, wlp_AD
! Setup
! ...Check internal structure
IF ( .NOT. iVar%Is_Valid ) THEN
Temperature_AD = ZERO
Salinity_AD = ZERO
Wind_Speed_AD = ZERO
RETURN
END IF
! ...Initialise local adjoint variables
w_int_AD = ZERO
w_AD = ZERO
sdd_AD = ZERO
sdd_int_AD = ZERO
Permittivity_AD = CMPLX(ZERO,ZERO,fp)
CALL Clear_LPoly(flp_AD)
CALL Clear_LPoly(wlp_AD)
! Emissivity calculation
Rh_Foam_AD = -iVar%Foam_Cover *Emissivity_AD(2)
Foam_Cover_AD = (iVar%Rh-iVar%Rh_Foam)*Emissivity_AD(2)
Rh_AD = (iVar%Foam_Cover-ONE) *Emissivity_AD(2)
Rv_Foam_AD = -iVar%Foam_Cover *Emissivity_AD(1)
Foam_Cover_AD = (iVar%Rv-iVar%Rv_Foam)*Emissivity_AD(1) + Foam_Cover_AD
Rv_AD = (iVar%Foam_Cover-ONE) *Emissivity_AD(1)
Emissivity_AD = ZERO
! Large scale correction calculation
Rh_Large_AD = Rh_AD
Rv_Large_AD = Rv_AD
CALL Large_Scale_Correction_AD( Rv_Large_AD, Rh_Large_AD, Wind_Speed_AD, &
iVar%Rv_Lterm, iVar%Rh_Lterm )
! Small scale correction calculation
Rv_Small_AD = iVar%Rv_Fresnel*Rv_AD
Rv_Fresnel_AD = iVar%Rv_Small*Rv_AD
Rv_AD = ZERO
Rh_Small_AD = iVar%Rh_Fresnel*Rh_AD
Rh_Fresnel_AD = iVar%Rh_Small*Rh_AD
Rh_AD = ZERO
CALL Small_Scale_Correction_AD( Rv_Small_AD, Rh_Small_AD, iVar%cos2_z, iVar%Frequency, &
sdd_int_AD, &
iVar%R_STerm )
! Foam coverage calculation
CALL Foam_Coverage_AD( iVar%Wind_Speed, Foam_Cover_AD, Wind_Speed_AD)
! Fresnel reflectivity calculation
CALL Fresnel_Reflectivity_AD( Rv_Fresnel_AD, Rh_Fresnel_AD, iVar%cos_z, &
Permittivity_AD, &
iVar%fVar)
! Permittivity Calculation
IF( iVar%Frequency < LOW_F_THRESHOLD ) THEN
CALL Guillou_Ocean_Permittivity_AD( Permittivity_AD, iVar%Frequency, &
Temperature_AD, Salinity_AD, &
iVar%gpVar)
ELSE
CALL Ellison_Ocean_Permittivity_AD( Permittivity_AD, &
Temperature_AD, &
iVar%epVar)
END IF
! Perform the adjoint interpolation
CALL Interp_2D_AD( sdd(iVar%i1:iVar%i2, iVar%j1:iVar%j2), & ! FWD Input
iVar%flp, iVar%wlp, & ! FWD Input
sdd_int_AD, & ! AD Input
sdd_AD, & ! AD Output
flp_AD , wlp_AD ) ! AD Output
! Compute the adjoint of the interpolating polynomials
! ...Wind speed term
CALL LPoly_AD( WIND_SPEED_SDD(iVar%j1:iVar%j2), & ! FWD Input
iVar%w_int , & ! FWD Input
iVar%wlp , & ! FWD Input
wlp_AD , & ! AD Input
w_AD , & ! AD Input
w_int_AD ) ! AD Output
! ...No frequency term LPoly_AD.
! The AD outputs
Wind_Speed_AD = Wind_Speed_AD + w_int_AD
END SUBROUTINE LowFrequency_MWSSEM_AD
!################################################################################
!################################################################################
!## ##
!## ## PRIVATE MODULE ROUTINES ## ##
!## ##
!################################################################################
!################################################################################
! =============================================================
! Routine for forward model foam reflectivity
! Function dependence is on zenith angle only
! so no TL or AD routine.
! See Eqns(18.44a) (18.44b) in
! Ulaby, F.T. et al. (1986) Microwave Remote Sensing, Active
! and Passive, vol.3, From Theory to Applications, pp1457.
! =============================================================
SUBROUTINE Foam_Reflectivity(z, Rv, Rh)
! Arguments
REAL(fp), INTENT(IN) :: z ! Zenith angle
REAL(fp), INTENT(OUT) :: Rv, Rh
! Parameters
REAL(fp), PARAMETER :: FR_COEFF(9) = &
(/ -9.946e-4_fp, 3.218e-5_fp, -1.187e-6_fp, &
7.e-20_fp, 0.07_fp, -1.748e-3_fp, &
-7.336e-5_fp, 1.044e-7_fp, -0.93_fp /)
! Local variables
REAL(fp) :: Fv, Fh
! The vertical component
Fv = ONE + z*(FR_COEFF(1)+ z*(FR_COEFF(2) + z*FR_COEFF(3))) + FR_COEFF(4)*z**10
Rv = FR_COEFF(5)
! The horizontal component
Fh = ONE + z*(FR_COEFF(6) + z*(FR_COEFF(7) + z*FR_COEFF(8)))
Rh = ONE + FR_COEFF(9)*Fh
END SUBROUTINE Foam_Reflectivity
! ======================================================
! Foam coverage routines
! See Eqn.(1) in
! Liu, Q. et al. (1998) Monte Carlo simulations of the
! microwave emissivity of the sea surface.
! JGR, Volume 103, No.C11, Pages 24983-24989
! ======================================================
! Forward model
SUBROUTINE Foam_Coverage(wind_speed, coverage)
REAL(fp), INTENT(IN) :: wind_speed
REAL(fp), INTENT(OUT) :: coverage
IF ( wind_speed < FOAM_THRESHOLD ) THEN
coverage = ZERO
ELSE
coverage = FC1 * (wind_speed**FC2)
END IF
END SUBROUTINE Foam_Coverage
! Tangent-linear model
SUBROUTINE Foam_Coverage_TL(wind_speed, wind_speed_TL, coverage_TL)
REAL(fp), INTENT(IN) :: wind_speed
REAL(fp), INTENT(IN) :: wind_speed_TL
REAL(fp), INTENT(OUT) :: coverage_TL
IF ( wind_speed < FOAM_THRESHOLD ) THEN
coverage_TL = ZERO
ELSE
coverage_TL = FC3 * (wind_speed**FC4) * wind_speed_TL
END IF
END SUBROUTINE Foam_Coverage_TL
! Adjoint model
SUBROUTINE Foam_Coverage_AD(wind_speed, coverage_AD, wind_speed_AD)
REAL(fp), INTENT(IN) :: wind_speed ! Input
REAL(fp), INTENT(IN OUT) :: coverage_AD ! Input
REAL(fp), INTENT(IN OUT) :: wind_speed_AD ! Output
IF ( .NOT. (wind_speed < FOAM_THRESHOLD) ) THEN
wind_speed_AD = wind_speed_AD + FC3*(wind_speed**FC4)*coverage_AD
END IF
coverage_AD = ZERO
END SUBROUTINE Foam_Coverage_AD
! ======================================================
! Reflectivity small scale correction routines
! See Eqns.(17a) and (17b) in
! Liu, Q. et al. (1998) Monte Carlo simulations of the
! microwave emissivity of the sea surface.
! JGR, Volume 103, No.C11, Pages 24983-24989
! ======================================================
! Forward model
SUBROUTINE Small_Scale_Correction( sdd, cos2_z, f, Rv, Rh, &
R_term )
! Arguments
REAL(fp), INTENT(IN) :: sdd ! Ocean surface height variance
REAL(fp), INTENT(IN) :: cos2_z ! cos^2 of zenith angle
REAL(fp), INTENT(IN) :: f ! Frequency
REAL(fp), INTENT(OUT) :: Rv, Rh ! Reflectivity correction
REAL(fp), INTENT(OUT) :: R_term ! Intermediate variable output
IF ( f > SMALLSCALE_F_THRESHOLD ) THEN
R_term = EXP(-sdd*cos2_z)
ELSE
R_term = ONE
END IF
Rv = R_term
Rh = R_term
END SUBROUTINE Small_Scale_Correction
! Tangent-linear model
SUBROUTINE Small_Scale_Correction_TL( sdd_TL, cos2_z, f, Rv_TL, Rh_TL, &
R_term )
! Arguments
REAL(fp), INTENT(IN) :: sdd_TL
REAL(fp), INTENT(IN) :: cos2_z
REAL(fp), INTENT(IN) :: f
REAL(fp), INTENT(OUT) :: Rv_TL, Rh_TL
REAL(fp), INTENT(IN) :: R_term ! Intermediate variable input
! Local variables
REAL(fp) :: R_term_TL
IF ( f > SMALLSCALE_F_THRESHOLD ) THEN
R_term_TL = -cos2_z * R_term * sdd_TL
ELSE
R_term_TL = ZERO
END IF
Rv_TL = R_term_TL
Rh_TL = R_term_TL
END SUBROUTINE Small_Scale_Correction_TL
! Adjoint model
SUBROUTINE Small_Scale_Correction_AD( Rv_AD, Rh_AD, cos2_z, f, sdd_AD, &
R_term )
! Arguments
REAL(fp), INTENT(IN OUT) :: Rv_AD, Rh_AD ! Input
REAL(fp), INTENT(IN) :: cos2_z ! Input
REAL(fp), INTENT(IN) :: f ! Input
REAL(fp), INTENT(IN OUT) :: sdd_AD ! Output
REAL(fp), INTENT(IN) :: R_term ! Intermediate variable input
! Local variables
REAL(fp) :: R_term_AD
R_term_AD = Rv_AD ; Rv_AD = ZERO
R_term_AD = R_term_AD + Rh_AD; Rh_AD = ZERO
IF ( f > SMALLSCALE_F_THRESHOLD ) THEN
sdd_AD = sdd_AD - cos2_z*R_term*R_term_AD
ELSE
sdd_AD = ZERO
END IF
END SUBROUTINE Small_Scale_Correction_AD
! ============================================
! Reflectivity large scale correction routines
! ============================================
! Forward model
SUBROUTINE Large_Scale_Correction( v, z, f, Rv, Rh, &
Rv_term, Rh_term )
! Arguments
REAL(fp), INTENT(IN) :: v ! Wind speed
REAL(fp), INTENT(IN) :: z ! Zenith angle
REAL(fp), INTENT(IN) :: f ! Frequency
REAL(fp), INTENT(OUT) :: Rv, Rh ! Reflectivity correction
REAL(fp), INTENT(OUT) :: Rv_term, Rh_term ! Intermediate variable output
! Local variables
REAL(fp) :: f_term
f_term = f / (LSC_COEFF(7) + f*LSC_COEFF(8))
Rv_Term = (LSC_COEFF(1) + z*(LSC_COEFF(2) + z*LSC_COEFF(3))) * f_term
Rh_term = (LSC_COEFF(4) + z*(LSC_COEFF(5) + z*LSC_COEFF(6))) * f_term
Rv = Rv_term * v
Rh = Rh_term * v
END SUBROUTINE Large_Scale_Correction
! Tangent-linear model
SUBROUTINE Large_Scale_Correction_TL( v_TL, Rv_TL, Rh_TL, &
Rv_term, Rh_term )
! Arguments
REAL(fp), INTENT(IN) :: v_TL
REAL(fp), INTENT(OUT) :: Rv_TL, Rh_TL
REAL(fp), INTENT(IN) :: Rv_term, Rh_term ! Intermediate variable input
Rv_TL = Rv_term * v_TL
Rh_TL = Rh_term * v_TL
END SUBROUTINE Large_Scale_Correction_TL
! Adjoint model
SUBROUTINE Large_Scale_Correction_AD( Rv_AD, Rh_AD, v_AD, &
Rv_term, Rh_term )
! Arguments
REAL(fp), INTENT(IN OUT) :: Rv_AD, Rh_AD ! Input
REAL(fp), INTENT(IN OUT) :: v_AD ! Output
REAL(fp), INTENT(IN) :: Rv_term, Rh_term ! Intermediate variable input
v_AD = v_AD + Rv_term*Rv_AD
v_AD = v_AD + Rh_term*Rh_AD
Rv_AD = ZERO
Rh_AD = ZERO
END SUBROUTINE Large_Scale_Correction_AD
END MODULE CRTM_LowFrequency_MWSSEM