Last modified: Fri Apr 19 10:48:08 2002.
NAME:
tangent_linear_rtm
PURPOSE:
PUBLIC function that calculates top-of-atmosphere (TOA) tangent-linear
radiances and brightness temperatures for an input atmospheric profile
set and user specified satellites/channels.
CATEGORY:
NCEP RTM
CALLING SEQUENCE:
result = tangent_linear_rtm( &
! Forward inputs
level_p, layer_p, layer_t, layer_w, layer_o, & ! Input, K x M
surface_temperature, & ! Input, M
surface_emissivity, & ! Input, L*M
surface_reflectivity, & ! Input, L*M
absorber, & ! Input, 0:K x J x M
tau_layer_index, & ! Input, K x J x M
flux_tau_layer_index, & ! Input, K x J x M
solar_tau_layer_index, & ! Input, K x J x M
tau_predictor, & ! Input, Imax x K x M
flux_tau_predictor, & ! Input, Imax x K x M
solar_tau_predictor, & ! Input, Imax x K x M
tau, & ! Input, K x L*M
flux_tau, & ! Input, K x L*M
solar_tau, & ! Input, K x L*M
layer_radiance, & ! Input, K x L*M
downwelling_radiance, & ! Input, L*M
upwelling_radiance, & ! Input, L*M
! -- Tangent-linear inputs
level_p_TL, layer_p_TL, layer_t_TL, layer_w_TL, layer_o_TL, & ! Input, K x M
surface_temperature_TL, & ! Input, M
surface_emissivity_TL, & ! Input, L*M
surface_reflectivity_TL, & ! Input, L*M
! -- Other inputs
secant_view_angle, & ! Input, M
secant_solar_angle, & ! Input, M
n_channels_per_profile, & ! Input, M
channel_index, & ! Input, L*M
! -- Tangent-linear outputs
tau_TL, & ! Output, K x L*M
flux_tau_TL, & ! Output, K x L*M
solar_tau_TL, & ! Output, K x L*M
layer_radiance_TL, & ! Output, K x L*M
downwelling_radiance_TL, & ! Output, L*M
upwelling_radiance_TL, & ! Output, L*M
brightness_temperature_TL, & ! Output, L*M
! Optional inputs
message_log = message_log )
INPUT ARGUMENTS:
level_p: Profile set layer interface pressure array. The TOA
pressure is not included. TOA pressure is parameterised
in the PARAMETERS module.
UNITS: hPa
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_p: Profile set layer average pressure array.
UNITS: hPa
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_t: Profile set layer average temperature array.
UNITS: Kelvin
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_w: . Profile set layer average water vapor mixing ratio array
UNITS: g/kg
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_o: Profile set layer average ozone mixing ratio array.
UNITS: ppmv
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
surface_temperature: Profile set surface temperature array.
UNITS: Kelvin
TYPE: Real
DIMENSION: M; M > or = 1 (i.e. scalar)
ATTRIBUTES: INTENT( IN )
surface_emissivity: Profile set surface emissivity array
UNITS: None
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( IN )
surface_reflectivity: Profile set surface reflectivity array
UNITS: None
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( IN )
absorber: Array of absorber amount for nadir view.
UNITS: Absorber dependent.
TYPE: Real
DIMENSION: 0:K x J x M
ATTRIBUTES: INTENT( IN )
tau_layer_index: Array of absorber space layer indices of the input
absorber amounts at the satellite view angle.
UNITS: None.
TYPE: Integer
DIMENSION: K x J x M
ATTRIBUTES: INTENT( IN )
flux_tau_layer_index: Array of absorber space layer indices of the input
absorber amounts at the default diffusivity angle.
UNITS: None.
TYPE: Integer
DIMENSION: K x J x M
ATTRIBUTES: INTENT( IN )
solar_tau_layer_index: Array of absorber space layer indices of the input
absorber amounts at the solar zenith angle.
UNITS: None.
TYPE: Integer
DIMENSION: K x J x M
ATTRIBUTES: INTENT( IN )
tau_predictor: Predictor profiles for the layer->TOA transmittance.
UNITS: None.
TYPE: Real
DIMENSION: I x K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
flux_tau_predictor: Predictor profiles for the thermal flux transmittance.
UNITS: None.
TYPE: Real
DIMENSION: I x K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
solar_tau_predictor: Predictor profiles for the solar transmittance.
UNITS: None.
TYPE: Real
DIMENSION: I x K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
tau: Layer->TOA transmittance for the satellite
view angle.
UNITS: None.
TYPE: Real
DIMENSION: K x L*M; K > 1, L > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
flux_tau: Layer->SFC transmittance for the default
diffusivity angle.
UNITS: None.
TYPE: Real
DIMENSION: K x L*M; K > 1, L > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
solar_tau: Layer->SFC transmittance for the solar
zenith angle.
UNITS: None.
TYPE: Real
DIMENSION: K x L*M; K > 1, L > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_radiance: Layer Planck radiances at every layer for
each channel/profile.
UNITS: mW/(m^2.sr.cm^-1)
TYPE: Real
DIMENSION: K x L*M; K > 1, L > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
downwelling_radiance: TOA->SFC radiances for each channel/profile due
to thermal flux and solar components.
UNITS: mW/(m^2.sr.cm^-1)
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( IN )
upwelling_radiance: TOA radiances for each channel/profile.
UNITS: mW/(m^2.sr.cm^-1)
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( IN )
level_p_TL: Profile set layer interface pressure tangent-linear
array.
UNITS: hPa
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_p_TL: Profile set layer average pressure tangent-linear
array.
UNITS: hPa
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_t_TL: Profile set layer average temperature tangent-linear
array.
UNITS: Kelvin
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_w_TL: . Profile set layer average water vapor mixing ratio
tangent-linear array.
UNITS: g/kg
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
layer_o_TL: Profile set layer average ozone mixing ratio
tangent-linear array.
UNITS: ppmv
TYPE: Real
DIMENSION: K x M; K > 1, and M > or = 1
ATTRIBUTES: INTENT( IN )
surface_temperature_TL: Profile set surface temperature tangent-linear array.
UNITS: Kelvin
TYPE: Real
DIMENSION: M; M > or = 1 (i.e. scalar)
ATTRIBUTES: INTENT( IN )
surface_emissivity_TL: Profile set surface emissivity tangent-linear array
UNITS: None
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( IN )
surface_reflectivity_TL: Profile set surface reflectivity tangent-linear array
UNITS: None
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( IN )
secant_view_angle: Secant of the satellite view angle measured
from nadir for each profile in the set.
UNITS: None
TYPE: Real
DIMENSION: M; M > or = 1 (i.e. scalar)
ATTRIBUTES: INTENT( IN )
secant_solar_angle: Secant of the solar zenith angle for each
profile in the set.
UNITS: None
TYPE: Real
DIMENSION: M; M > or = 1 (i.e. scalar)
ATTRIBUTES: INTENT( IN )
n_channels_per_profile: The number of channels for each profile in the
set for which radiances are required.
UNITS: None
TYPE: Integer
DIMENSION: M; M > or = 1 (i.e. scalar)
ATTRIBUTES: INTENT( IN )
channel_index: Channel index id array. Each element is a unique
index to a (supported) sensor channel.
UNITS: None
TYPE: Integer
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( IN )
OPTIONAL INPUT ARGUMENTS:
message_log: Character string specifying a filename in which any
messages will be logged. If not specified, or if an
error occurs opening the log file, the default action
is to output messages to the screen.
UNITS: None
TYPE: Character
DIMENSION: Scalar
ATTRIBUTES: INTENT( IN ), OPTIONAL
OUTPUT ARGUMENTS:
tau_TL: Layer->TOA tangent-linear transmittance for the satellite
view angle.
UNITS: None.
TYPE: Real
DIMENSION: K x L*M; K > 1, L > 1, and M > or = 1
ATTRIBUTES: INTENT( OUT )
flux_tau_TL: Layer->SFC tangent-linear transmittance for the default
diffusivity angle.
UNITS: None.
TYPE: Real
DIMENSION: K x L*M; K > 1, L > 1, and M > or = 1
ATTRIBUTES: INTENT( OUT )
solar_tau_TL: Layer->SFC tangent-linear transmittance for the solar
zenith angle.
UNITS: None.
TYPE: Real
DIMENSION: K x L*M; K > 1, L > 1, and M > or = 1
ATTRIBUTES: INTENT( OUT )
layer_radiance_TL: Layer Planck tangent-linear radiances at every layer for
each channel/profile.
UNITS: mW/(m^2.sr.cm^-1)
TYPE: Real
DIMENSION: K x L*M; K > 1, L > 1, and M > or = 1
ATTRIBUTES: INTENT( OUT )
downwelling_radiance_TL: TOA->SFC tangent-linear radiances for each channel/profile due
to thermal flux and solar components.
UNITS: mW/(m^2.sr.cm^-1)
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( OUT )
upwelling_radiance_TL: TOA tangent-linear radiances for each channel/profile.
UNITS: mW/(m^2.sr.cm^-1)
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( OUT )
brightness_temperature_TL: Tangent-linear temperatures corresponding to the
TOA tangent-linear radiances.
UNITS: Kelvin
TYPE: Real
DIMENSION: L*M; L > 1, and M > or = 1
NB: This is a 1-D array.
ATTRIBUTES: INTENT( OUT )
OPTIONAL OUTPUT ARGUMENTS:
None.
FUNCTION RESULT:
Result = SUCCESS => Calculation was successful
= FAILURE => Error occurred checking input arguments
CALLS:
display_message: Subroutine to output messages
SOURCE: error_handler module
get_max_n_channels: Routine to retrieve the value of the
MAX_N_CHANNELS "pseudo-parameter".
SOURCE: parameters module
compute_absorber_amount_TL: Subroutine to integrate the tangent-linear
absorber profiles
SOURCE: absorber_profile module
compute_predictors_TL: Subroutine to compute the tangent-linear
transmittance predictor profiles.
SOURCE: predictor module
compute_transmittance_TL: Subroutine to compute the tangent-linear
transmittance profiles.
SOURCE: transmittance module
compute_radiance_TL: Subroutine to compute the TOA tangent-linear
radiances and brightness temperatures.
SOURCE: radiance module
EXTERNALS:
None
COMMON BLOCKS:
None.
SIDE EFFECTS:
None known.
RESTRICTIONS:
Note the restrictions on the input array dimensions:
K == n_layers > 1
L == n_channels > 1
M == n_profiles > or = 1
PROCEDURE:
See individual module function documentation.
(See tangent_linear_model.f90)