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!
! ODAS_AtmAbsorption
!
! Module containing routines to compute the optical depth profile
! due to gaseous absorption for the Optical Depth Absorber Space (ODAS)
! model.
!
!
! CREATION HISTORY:
! Written by: Paul van Delst, 13-May-2004
! paul.vandelst@noaa.gov
!
! Modifed by: Yong Han, 25-June-2008
! yong.han@noaa.gov
!
<A NAME='ODAS_ATMABSORPTION'><A href='../../html_code/crtm/ODAS_AtmAbsorption.f90.html#ODAS_ATMABSORPTION' TARGET='top_target'><IMG SRC="../../gif/bar_purple.gif" border=0></A>
MODULE ODAS_AtmAbsorption 2,9
! -----------------
! Environment setup
! -----------------
! Module use
USE Type_Kinds
, ONLY: fp
USE Message_Handler, ONLY: SUCCESS, FAILURE, WARNING, Display_Message
USE CRTM_Parameters, ONLY: ZERO, &
MAX_N_LAYERS, &
LIMIT_EXP, &
LIMIT_LOG
USE CRTM_Atmosphere_Define, ONLY: CRTM_Atmosphere_type
USE CRTM_GeometryInfo_Define, ONLY: CRTM_GeometryInfo_type
USE CRTM_AtmOptics_Define, ONLY: CRTM_AtmOptics_type
USE ODAS_Predictor_Define, ONLY: ODAS_Predictor_type
USE ODAS_Predictor, ONLY: MAX_N_ABSORBERS, &
MAX_N_ORDERS, &
MAX_N_PREDICTORS_USED, &
MAX_N_ORDERS
USE ODAS_TauCoeff, ONLY: TC, &
ODAS_TauCoeff_type
! Disable implicit typing
IMPLICIT NONE
! ------------
! Visibilities
! ------------
! Everything private by default
PRIVATE
! Science routines in this modules
PUBLIC :: ODAS_Compute_AtmAbsorption
PUBLIC :: ODAS_Compute_AtmAbsorption_TL
PUBLIC :: ODAS_Compute_AtmAbsorption_AD
! Internal variable structure
PUBLIC :: iVar_type
! -----------------
! Module parameters
! -----------------
CHARACTER(*), PARAMETER :: MODULE_VERSION_ID = &
'$Id: ODAS_AtmAbsorption.f90 29405 2013-06-20 20:19:52Z paul.vandelst@noaa.gov $'
! ------------------------------------------
! Structure definition to hold forward model
! variables across FWD, TL, and AD calls
! ------------------------------------------
TYPE :: iVar_type
PRIVATE
REAL(fp), DIMENSION(MAX_N_LAYERS, &
0:MAX_N_PREDICTORS_USED, &
MAX_N_ABSORBERS) :: b
REAL(fp), DIMENSION(MAX_N_LAYERS,MAX_N_ABSORBERS) :: LN_Chi
REAL(fp), DIMENSION(MAX_N_LAYERS,MAX_N_ABSORBERS) :: Chi
END TYPE iVar_type
CONTAINS
!################################################################################
!################################################################################
!## ##
!## ## PUBLIC MODULE ROUTINES ## ##
!## ##
!################################################################################
!################################################################################
!------------------------------------------------------------------------------
!:sdoc+:
!
! NAME:
! ODAS_Compute_AtmAbsorption
!
! PURPOSE:
! Subroutine to calculate the layer optical depths due to gaseous
! absorption for a given sensor and channel and atmospheric profile
! using the Optical Depth in Absorber Space (ODAS) algorithm).
!
! CALLING SEQUENCE:
! CALL ODAS_Compute_AtmAbsorption( TC , &
! ChannelIndex, &
! Predictor , &
! AtmOptics , &
! iVar )
!
! INPUTS:
! TC: Structure containing ODAS model coefficient data
! for a sensor.
! UNITS: N/A
! TYPE: ODAS_TauCoeff_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN OUT)
!
! ChannelIndex: Channel index id. This is a unique index associated
! with a (supported) sensor channel used to access the
! shared coefficient data for a particular sensor's
! channel.
! See the SensorIndex argument.
! UNITS: N/A
! TYPE: INTEGER
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Predictor: Structure containing the ODAS model integrated
! absorber and predictor profile data.
! UNITS: N/A
! TYPE: ODAS_Predictor_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! OUTPUTS:
! AtmOptics: Structure containing computed optical depth
! profile data.
! UNITS: N/A
! TYPE: CRTM_AtmOptics_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN 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(IN OUT)
!
! COMMENTS:
! Note the INTENT on the output structure arguments are IN OUT to prevent
! reinitialisation upon entry.
!
!:sdoc-:
!------------------------------------------------------------------------------
<A NAME='ODAS_COMPUTE_ATMABSORPTION'><A href='../../html_code/crtm/ODAS_AtmAbsorption.f90.html#ODAS_COMPUTE_ATMABSORPTION' TARGET='top_target'><IMG SRC="../../gif/bar_red.gif" border=0></A>
SUBROUTINE ODAS_Compute_AtmAbsorption( & 3
TC , & ! Input
ChannelIndex, & ! Input
Predictor , & ! Input
AtmOptics , & ! Output
iVar ) ! Internal variable output
! Arguments
TYPE(ODAS_TauCoeff_type) , INTENT(IN) :: TC
INTEGER , INTENT(IN) :: ChannelIndex
TYPE(ODAS_Predictor_type), INTENT(IN) :: Predictor
TYPE(CRTM_AtmOptics_type), INTENT(IN OUT) :: AtmOptics
TYPE(iVar_type) , INTENT(IN OUT) :: iVar
! Local variables
INTEGER :: l ! Channel index
INTEGER :: k ! Layer index
INTEGER :: j ! Absorber index
INTEGER :: i, ip ! Predictor index
INTEGER :: np ! # of predictors
INTEGER :: ps ! starting position of the coefficient subset for given j and l
INTEGER :: n_Orders ! order of the polynomial function
INTEGER :: ic_0 ! the index of the first coefficient in the C coeff subset for deriving the B coeff.
INTEGER :: ic ! the index of the coefficients
REAL(fp) :: c ! a coefficient
INTEGER :: n_Layers
! Set up
! ...Assign the indices to a short name
l = ChannelIndex
n_Layers = Predictor%n_Layers
! ...Initilise the optical depth
AtmOptics%Optical_Depth = ZERO !! *** DOES THIS MAKE ROUTINE ORDER DEPENDENT? ***
! Loop over each absorber for optical depth calculation
Absorber_Loop: DO j = 1, Predictor%n_Absorbers
! Check if there is any absorption for this
! absorber/channel combination.
np = TC%Pre_Index(0,j,l)
IF ( np < 0 ) CYCLE Absorber_Loop
! Compute the coefficients for use with the atmospheric predictors
!
! For every atmospheric predictor, Pred(i), the coefficient
! associated with it, b(i), at a particular absorber amount
! level, k, is given by an N'th order polynomial,
!
! __ N
! \ np
! b(i) = > c(np,i).k
! /__
! np=0
!
ps = TC%Pos_Index(j,l) ! starting position of the coefficient subset for given j and l
n_Orders = TC%Order(j,l)
! ...Compute b(0)
ic_0 = ps
iVar%b(1:n_Layers,0,j) = TC%C(ic_0)
DO ic = 1, n_Orders
c = TC%C(ic_0 + ic)
DO k = 1, n_Layers
iVar%b(k,0,j) = iVar%b(k,0,j) + (c * Predictor%Ap(k, ic, j))
END DO
END DO
! compute b(i) coefficients (i > 0)
! Compute the logarithm of the absorption coefficient
!
! The logarithm of the absorption coefficient, LN(chi), is
! determined from the regression equation,
!
! __Iuse
! \
! LN(chi) = b(0) + > b(i).X(i)
! /__
! i=1
!
! ...The b(0) contribution
iVar%LN_Chi(1:n_Layers, j) = iVar%b(1:n_Layers,0,j)
DO i = 1, np
! ...b(i) term, i > 0
ic_0 = ps + i*(n_orders+1)
iVar%b(1:n_Layers,i,j) = TC%C(ic_0)
DO ic = 1, n_Orders
c = TC%C(ic_0 + ic)
DO k = 1, n_Layers
iVar%b(k,i,j) = iVar%b(k,i,j) + (c * Predictor%Ap(k, ic, j))
END DO
END DO
! ...b(i) term contribution
ip = TC%Pre_Index(i,j,l)
DO k = 1, n_Layers
iVar%LN_Chi(k,j) = iVar%LN_Chi(k,j) + (iVar%b(k, i, j) * Predictor%X(k,ip))
END DO
END DO
! Compute the optical depth profile
DO k = 1, n_Layers
! ...Compute the absorption coefficient
IF( iVar%LN_Chi(k,j) > LIMIT_EXP ) THEN
iVar%Chi(k,j) = LIMIT_LOG
ELSE IF( iVar%LN_Chi(k,j) < -LIMIT_EXP ) THEN
iVar%Chi(k,j) = ZERO
ELSE
iVar%Chi(k,j) = EXP(iVar%LN_Chi(k,j))
ENDIF
AtmOptics%Optical_Depth(k) = AtmOptics%Optical_Depth(k) + (iVar%Chi(k,j) * Predictor%dA(k,j))
END DO
END DO Absorber_Loop
! Scale the optical depth to nadir
AtmOptics%Optical_Depth = AtmOptics%Optical_Depth / Predictor%Secant_Sensor_Zenith
END SUBROUTINE ODAS_Compute_AtmAbsorption
!------------------------------------------------------------------------------
!:sdoc+:
!
! NAME:
! ODAS_Compute_AtmAbsorption_TL
!
! PURPOSE:
! Subroutine to calculate the tangent-linear layer optical depths due
! to gaseous absorption for a given sensor and channel and atmospheric
! profile using the Optical Depth in Absorber Space (ODAS) algorithm).
!
! CALLING SEQUENCE:
! CALL ODAS_Compute_AtmAbsorption_TL( TC , &
! ChannelIndex, &
! Predictor , &
! Predictor_TL, &
! AtmOptics_TL, &
! iVar )
!
! INPUTS:
! TC: Structure containing ODAS model coefficient data
! for a sensor.
! UNITS: N/A
! TYPE: ODAS_TauCoeff_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! ChannelIndex: Channel index id. This is a unique index associated
! with a (supported) sensor channel used to access the
! shared coefficient data for a particular sensor's
! channel.
! See the SensorIndex argument.
! UNITS: N/A
! TYPE: INTEGER
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Predictor: Structure containing the ODAS model integrated
! absorber and predictor profile data.
! UNITS: N/A
! TYPE: ODAS_Predictor_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Predictor_TL: Structure containing the ODAS model tangent-linear
! integrated absorber and predictor profile data.
! UNITS: N/A
! TYPE: ODAS_Predictor_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! 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(IN)
!
! OUTPUTS:
! AtmOptics_TL: Structure containing the computed tangent-linear
! optical depth profile data.
! UNITS: N/A
! TYPE: CRTM_AtmOptics_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN OUT)
!
! Note the INTENT on the output structure arguments are IN OUT to prevent
! reinitialisation upon entry.
!
!:sdoc-:
!------------------------------------------------------------------------------
<A NAME='ODAS_COMPUTE_ATMABSORPTION_TL'><A href='../../html_code/crtm/ODAS_AtmAbsorption.f90.html#ODAS_COMPUTE_ATMABSORPTION_TL' TARGET='top_target'><IMG SRC="../../gif/bar_red.gif" border=0></A>
SUBROUTINE ODAS_Compute_AtmAbsorption_TL( & 3
TC , & ! Input
ChannelIndex, & ! Input
Predictor , & ! FWD Input
Predictor_TL, & ! TL Input
AtmOptics_TL, & ! TL Output
iVar ) ! Internal variable input
! Arguments
TYPE(ODAS_TauCoeff_type) , INTENT(IN) :: TC
INTEGER , INTENT(IN) :: ChannelIndex
TYPE(ODAS_Predictor_type), INTENT(IN) :: Predictor
TYPE(ODAS_Predictor_type), INTENT(IN) :: Predictor_TL
TYPE(CRTM_AtmOptics_type), INTENT(IN OUT) :: AtmOptics_TL
TYPE(iVar_type) , INTENT(IN) :: iVar
! Local variables
INTEGER :: l ! Channel index
INTEGER :: k ! Layer index
INTEGER :: j ! Absorber index
INTEGER :: i, ip ! Predictor index
INTEGER :: np ! # of predictors
INTEGER :: ps ! starting position of the coefficient subset for given j and l
INTEGER :: n_Orders ! order of the polynomial function
INTEGER :: ic_0 ! the index of the first coefficient in the b coeff subset for deriving the b coeff.
INTEGER :: ic ! the index of the coefficients
REAL(fp) :: c ! a coefficient
REAL(fp) :: b_TL(Predictor%n_layers)
REAL(fp) :: LN_Chi_TL(Predictor%n_layers)
REAL(fp) :: Chi_TL
INTEGER :: n_Layers
! Set up
! ...Assign the indices to a short name
l = ChannelIndex
n_Layers = Predictor%n_Layers
! ...Initilise the tangent-linear optical depth
AtmOptics_TL%Optical_Depth = ZERO
! Loop over each absorber for optical depth calculation
Absorber_Loop: DO j = 1, Predictor%n_Absorbers
! Check if there is any absorption for this
! absorber/channel combination.
np = TC%Pre_Index(0,j,l)
IF ( np < 0 ) CYCLE Absorber_Loop
! Compute the coefficients for use with the atmospheric predictors
!
! For every atmospheric predictor, Pred(i), the coefficient
! associated with it, b(i), at a particular absorber amount
! level, k, is given by an N'th order polynomial,
!
! __ N
! \ np
! b(i) = > c(np,i).k
! /__
! np=0
!
ps = TC%Pos_Index(j,l) ! starting position of the coefficient subset f or given j and l
n_orders = TC%Order(j,l)
! ...Compute b_TL(0)
ic_0 = ps
b_TL(1:n_Layers) = ZERO
DO ic = 1, n_Orders
c = TC%C(ic_0 + ic)
DO k = 1, n_Layers
b_TL(k) = b_TL(k) + (c * Predictor_TL%Ap(k, ic, j))
END DO
END DO
! Compute the logarithm of the absorption coefficient
!
! The logarithm of the absorption coefficient, LN(chi), is
! determined from the regression equation,
!
! __Iuse
! \
! LN(chi) = b(0) + > b(i).X(i)
! /__
! i=1
!
! ...b_TL(0) term contribution
LN_Chi_TL(1:n_Layers) = b_TL(1:n_Layers)
DO i = 1, np
! ...b_TL(i) term, i > 0
ic_0 = ps + i*(n_orders+1)
b_TL(1:n_Layers) = ZERO
DO ic = 1, n_Orders
c = TC%C(ic_0 + ic)
DO k = 1, n_Layers
b_TL(k) = b_TL(k) + (c * Predictor_TL%Ap(k, ic, j))
END DO
END DO
! b_TL(i) term contribution
ip = TC%Pre_Index(i,j,l)
DO k = 1, n_Layers
LN_Chi_TL(k) = LN_Chi_TL(k) + (b_TL(k) * Predictor%X(k,ip)) &
+ (iVar%b(k,i,j) * Predictor_TL%X(k,ip))
END DO
END DO
! Compute the tangent-linear optical depth profile
DO k = 1, n_Layers
! ...Compute the tangent-linear absorption coefficient
IF( iVar%LN_Chi(k,j) > LIMIT_EXP ) THEN
Chi_TL = ZERO
ELSE IF( iVar%LN_Chi(k,j) < -LIMIT_EXP ) THEN
Chi_TL = ZERO
ELSE
Chi_TL = iVar%Chi(k,j) * LN_Chi_TL(k)
ENDIF
AtmOptics_TL%Optical_Depth(k) = AtmOptics_TL%Optical_Depth(k) &
+ (Chi_TL * Predictor%dA(k,j)) &
+ (iVar%Chi(k,j) * Predictor_TL%dA(k,j))
END DO
END DO Absorber_Loop
! Scale the tangent-linear optical depth to nadir
AtmOptics_TL%Optical_Depth = AtmOptics_TL%Optical_Depth / &
Predictor%Secant_Sensor_Zenith
END SUBROUTINE ODAS_Compute_AtmAbsorption_TL
!--------------------------------------------------------------------------------
!:sdoc+:
!
! NAME:
! ODAS_Compute_AtmAbsorption_AD
!
! PURPOSE:
! Subroutine to calculate the adjoint of the layer optical depths due
! to gaseous absorption for a given sensor and channel and atmospheric
! profile using the Optical Depth in Absorber Space (ODAS) algorithm).
!
! CALLING SEQUENCE:
! CALL ODAS_Compute_AtmAbsorption_AD( TC , &
! ChannelIndex, &
! Predictor , &
! AtmOptics_AD, &
! Predictor_AD, &
! iVar )
!
! INPUTS:
! TC: Structure containing ODAS model coefficient data
! for a sensor.
! UNITS: N/A
! TYPE: ODAS_TauCoeff_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! ChannelIndex: Channel index id. This is a unique index associated
! with a (supported) sensor channel used to access the
! shared coefficient data for a particular sensor's
! channel.
! UNITS: N/A
! TYPE: INTEGER
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! Predictor: Structure containing the ODAS model integrated
! absorber and predictor profile data.
! UNITS: N/A
! TYPE: ODAS_Predictor_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN)
!
! AtmOptics_AD: Structure containing the adjoint optical depth
! profile data.
! *** NOTE: Optical depth component set to zero on output. ***
! UNITS: N/A
! TYPE: CRTM_AtmOptics_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN 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(IN)
!
! OUTPUTS:
! Predictor_AD: Structure containing the ODAS model adjoint
! integrated absorber and predictor profile data.
! *** NOTE: Must contain a value upon input. ***
! UNITS: N/A
! TYPE: ODAS_Predictor_type
! DIMENSION: Scalar
! ATTRIBUTES: INTENT(IN OUT)
!
! SIDE EFFECTS:
! Components of the AtmOptics_AD structure argument are modified
! in this function.
!
!:sdoc-:
!------------------------------------------------------------------------------
<A NAME='ODAS_COMPUTE_ATMABSORPTION_AD'><A href='../../html_code/crtm/ODAS_AtmAbsorption.f90.html#ODAS_COMPUTE_ATMABSORPTION_AD' TARGET='top_target'><IMG SRC="../../gif/bar_red.gif" border=0></A>
SUBROUTINE ODAS_Compute_AtmAbsorption_AD( & 3
TC , & ! Input
ChannelIndex, & ! Input
Predictor , & ! FWD Input
AtmOptics_AD, & ! AD Input
Predictor_AD, & ! AD Output
iVar ) ! Internal variable input
! Arguments
TYPE(ODAS_TauCoeff_type) , INTENT(IN) :: TC
INTEGER , INTENT(IN) :: ChannelIndex
TYPE(ODAS_Predictor_type), INTENT(IN) :: Predictor
TYPE(CRTM_AtmOptics_type), INTENT(IN OUT) :: AtmOptics_AD
TYPE(ODAS_Predictor_type), INTENT(IN OUT) :: Predictor_AD
TYPE(iVar_type) , INTENT(IN) :: iVar
! Local variables
INTEGER :: l ! Channel index
INTEGER :: k ! Layer index
INTEGER :: j ! Absorber index
INTEGER :: i, ip ! Predictor index
INTEGER :: np ! # of predictors
INTEGER :: ps ! starting position of the coefficient subset for given j and l
INTEGER :: n_Orders ! order of the polynomial function
INTEGER :: ic_0 ! the index of the first coefficient in the b coeff subset for deriving the b coeff.
INTEGER :: ic ! the index of the coefficients
REAL(fp) :: c ! a coefficient
REAL(fp) :: b_AD(Predictor%n_layers)
REAL(fp) :: LN_Chi_AD(Predictor%n_layers)
REAL(fp) :: Chi_AD
INTEGER :: n_Layers
! Set up
! ...Assign the indices to a short name
l = ChannelIndex
n_Layers = Predictor%n_Layers
! ...Initialise local adjoint variables
b_AD = ZERO
LN_Chi_AD = ZERO
Chi_AD = ZERO
! Compute adjoint nadir optical depth profile
AtmOptics_AD%Optical_Depth = AtmOptics_AD%Optical_Depth / &
Predictor%Secant_Sensor_Zenith
! Loop over each absorber for optical depth calculation
Absorber_loop: DO j = 1, Predictor%n_Absorbers
! Check if there is any absorption for this
! absorber/channel combination.
np = TC%Pre_Index(0,j,l)
IF ( np < 0 ) CYCLE Absorber_Loop
! Starting position of the coefficient subset for given absorber (j) and channels(l)
ps = TC%Pos_Index(j,l)
n_orders = TC%Order(j,l)
! Compute the adjoint of the optical depth profile
DO k = n_Layers, 1, -1
Predictor_AD%dA(k,j) = Predictor_AD%dA(k,j) + &
(iVar%Chi(k,j) * AtmOptics_AD%Optical_Depth(k))
Chi_AD = Chi_AD + (Predictor%dA(k,j) * AtmOptics_AD%Optical_Depth(k))
! ...Compute the adjoint of the absorption coefficient
IF( iVar%LN_Chi(k,j) > LIMIT_EXP ) THEN
Chi_AD = ZERO
ELSE IF( iVar%LN_Chi(k,j) < -LIMIT_EXP ) THEN
Chi_AD = ZERO
ELSE
LN_Chi_AD(k) = LN_Chi_AD(k) + iVar%Chi(k,j) * Chi_AD
Chi_AD = ZERO
ENDIF
END DO
! Compute the adjoint of the logarithm of the absorption coefficient
DO i = np, 1, -1
! ...b(i) term contribution
ip = TC%Pre_Index(i,j,l)
DO k = n_Layers, 1, -1
b_AD(k) = b_AD(k) + (LN_Chi_AD(k) * Predictor%X(k,ip))
Predictor_AD%X(k,ip) = Predictor_AD%X(k,ip) + (iVar%b(k,i,j) * LN_Chi_AD(k))
END DO
! ...b(i) term, i > 0
ic_0 = ps + i*(n_orders+1)
DO ic = n_Orders, 1, -1
c = TC%C(ic_0 + ic)
DO k = n_Layers, 1, -1
Predictor_AD%Ap(k, ic, j) = Predictor_AD%Ap(k, ic, j) + (c * b_AD(k))
END DO
END DO
b_AD(1:n_Layers) = ZERO
END DO
b_AD(1:n_Layers) = b_AD(1:n_Layers) + LN_Chi_AD(1:n_Layers)
LN_Chi_AD(1:n_Layers) = ZERO
! Compute the adjoint of the b(i) coefficients
ic_0 = ps
DO ic = n_Orders, 1, -1
c = TC%C(ic_0 + ic)
DO k = n_Layers, 1, -1
Predictor_AD%Ap(k, ic, j) = Predictor_AD%Ap(k, ic, j) + (c * b_AD(k))
END DO
END DO
b_AD(1:n_Layers) = ZERO
END DO Absorber_Loop
! No more impact of optical depth on derivatives
AtmOptics_AD%Optical_Depth = ZERO
END SUBROUTINE ODAS_Compute_AtmAbsorption_AD
END MODULE ODAS_AtmAbsorption