Main program to compute radiance bias correction coefficients by linear regression.
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Algorithm
O-A are computed from input analysis fields resulting from a stand alone
3DVar analysis assimilating only anchoring observations (considered as “trials”)
and bgckalt files.
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File I/O
The required input files and produced output files are listed as follows.
Input and Output Files (NWP application)
Description of file
flnml
In - Main namelist file with parameters user may modify
flnml_static
In - The “static” namelist that should not be modified
trlm_$NN (e.g. trlm_01)
In - Background state (a.k.a. trial) files for each timestep
analysisgrid
In - File defining grid for computing the analysis increment
obsfiles_$FAM/obs$FAM_$NNNN_$NNNN
In - Observation file for each “family” and MPI task
Remainder are files related to radiance obs:
stats_tovs
In - Observation error file for radiances
stats_tovs_symmetricObsErr
In - user-defined symmetric TOVS errors for all sky
Cmat_$PLATFORM_$SENSOR.dat
In - Inter-channel observation-error correlations
rtcoef_$PLATFORM_$SENSOR.H5
In - RTTOV coefficient file HDF-5 format
rtcoef_$PLATFORM_$SENSOR.dat
In - RTTOV coefficient file ASCII format
ozoneclim98
In - ozone climatology standard file (Fortuin and Kelder)
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Synopsis
Below is a summary of the genCoeff program calling sequence:
Initial setups:
Setup time grid using initial time from trlm_01
Setup horizontal and vertical grid objects for “analysis
grid” from analysisgrid file.
Setup obsSpaceData object and read observations from
files: inn_setupObs.
Setup columnData and gridStateVector modules (read
list of analysis variables from namelist) and allocate column
object for storing trial on analysis levels.
Setup the observation error statistics in obsSpaceData
object: oer_setObsErrors.
Allocate a stateVector object on the trial grid and then
read the trials: gio_readTrials.
Coefficients computation
Horizontally Interpolate “trial” fields to trial columns
if needed substract bias correction from ObsSpaceData to get raw O-F and obs.
Remove outliers
Compute innovation from “trial” fields
Refresh Bias Correction (probably useless)
Perform linear regression
write coefficients to output file.
if requested compute and output to file raw (.i.e without bias correction) O-F statistics
compute and apply bias coorection to obsSpace Data
if requested compute and output to file bias corrected O-F statistics
Final step
deallocate memory (radiance bias correction module and obsSpaceData)