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Observation pre-processing in the ARPEGE/ALADIN model Observation pre-processing in the ARPEGE/ALADIN model Roger Randriamampianina Roger Randriamampianina.

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Presentation on theme: "Observation pre-processing in the ARPEGE/ALADIN model Observation pre-processing in the ARPEGE/ALADIN model Roger Randriamampianina Roger Randriamampianina."— Presentation transcript:

1 Observation pre-processing in the ARPEGE/ALADIN model Observation pre-processing in the ARPEGE/ALADIN model Roger Randriamampianina Roger Randriamampianina Hungarian Meteorological Service Hungarian Meteorological Service ALADIN 3D-Var/ODB training course, Budapest, 6-10 June, 2006

2 Local pre-processing: OULAN BATOR 1C RAD. BIAS CORRECTION Outline

3 Rad 1C BIAS CORRECTION

4 Bias correction procedure [Harris and Kelly (2001)] To compute average differences for each scan position Where: - observed radiance difference [y-H(x)] - the average observed radiance To compute air-mass bias coefficients -variance; Dj - departure in channel j; X – predictor vector Xi

5 BIAS COEFFICIENTS …

6 ! Convert all temperatures to virtual temperatures tv(:,JPF) = temp(:,JPF)/( *hum(:,JPF)) ! Construct averages for NESDIS thick layers pred(1,JPF) = Kth * 0.5 * SUM((tv(26:37,JPF) + tv(25:36,JPF))& * DLP(25:36)) pred(2,JPF) = Kth * 0.5 * SUM((tv(14:21,JPF) + tv(13:20,JPF))& * DLP(13:20)) pred(3,JPF) = T_skin(JPF) pred(4,JPF) = Kpc * 0.5 * SUM((hum(2:43,JPF) + hum(1:42,JPF))& * DP(1:42)) pred(5,JPF) = Kth * 0.5 * SUM((tv(5:8,JPF) + tv(4:7,JPF))& * DLP(4:7)) pred(6,JPF) = Kth * 0.5 * SUM((tv(8:13,JPF) + tv(7:12,JPF))& * DLP(7:12)) Bias correction procedure – changing the predictors getpred.F90

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10 Bias correction procedure script We need the (radiance) observation departures after screening (ECMA) /operativ/aladin/workdir/assim/bcorr OWNER=wshop01 ; export OWNER USER=wshop01 ; export USER CLASS=mf ; export CLASS EXPVER=J1C ; export EXPVER EXPNAME=SUBFU INITIME= ; export INITIME BASETIME= LASTDATE= BIASDAYS=11 ; export BIASDAYS …. Check the WLIB; WOBS; WHERE parameters In the script run_bias (run_bias_new_oper or run_bias_new_oper_fb) We need 3 scripts: run_bias, bias_noaa and bias_calc The scripts are located in ~wshop01/Preproc/bcorr/Script and ~wshop01/Preproc/bcorr/Script/full_grid

11 Bias correction procedure script In the script bias_noaa (bias_noaa_new_oper or bias_noaa_new_oper_fb) NUM_SAT=6 # Number of satellites to treat set -A SATID # List of satellites to extract set -A NOAAID # METEOSAT/NOAA/DMSP numbers set -A SENSOR # 0=HIRS/MET,1=MSU,2=SSU,3=AMSU,6=SSM/I set -A NBCHAN # no. of channels to be read set -A NY # channels used and land/sea channel mask set -A USE_SAT # Set to 1 to process satellite, 0 to skip set -A HOURLY # 0/1 : evaluations in 6h/1h slots set -A MONITORING # 0/1 : do monitoring set -A SCANNUM # Number of scan positions set -A RMASK # Use of radiosonde mask 1 yes, 0 no set -A SCORR # Use of scan correction 1 yes, 0 no set -A NEIGN # Number of eigenvectors 4 tovs 3 ssmi set -A NPRED # Number of predictors 6 tovs 4 ssmi Please check the other following variables/settings …

12 Bias correction procedure (script) In the script bias_calc (bias_calc_new_oper or bias_calc_new_oper_fb) YPFTABB="fb${SATTYPE}${CYDATE}" NUMSATS=$NUM_SAT IHOURLY(1) = ${HOURLY[0]} IHOURLY(2) = ${HOURLY[1]} IHOURLY(3) = ${HOURLY[2]} IHOURLY(4) = ${HOURLY[3]} IHOURLY(5) = ${HOURLY[4]} IHOURLY(6) = ${HOURLY[5]} SATS(1) = ${SATID[0]} SATS(2) = ${SATID[1]} SATS(3) = ${SATID[2]} SATS(4) = ${SATID[3]} SATS(5) = ${SATID[4]} SATS(6) = ${SATID[5]} IRTYPES(1) = ${SENSOR[0]} IRTYPES(2) = ${SENSOR[1]} IRTYPES(3) = ${SENSOR[2]} IRTYPES(4) = ${SENSOR[3]} IRTYPES(5) = ${SENSOR[4]} IRTYPES(6) = ${SENSOR[5]} INBCHAN(1) = ${NBCHAN[0]} INBCHAN(2) = ${NBCHAN[1]} INBCHAN(3) = ${NBCHAN[2]} INBCHAN(4) = ${NBCHAN[3]} INBCHAN(5) = ${NBCHAN[4]} INBCHAN(6) = ${NBCHAN[5]} /END ENDA prepare NAMELIST FILE for FB - decoding/extraction program cycle_biasprep cat > nml_biasprep << ENDA … check also nml_biasconv

13 Bias correction procedure - compilation We will compile two versions of the procedure 1- with 30 scan angles (resolution of full AMSU-A grid) 2- with 90 scan angles (resolution of full AMSU-B grid) (1)~{user}/Preproc/bcorr 9 executables (9 Makefiles) (2)(2) ~{user}/Preproc/bcorr/full_grid 9 executables ADD_BIAS (add_bias_1c) - Adds together bias 'core' array files for input to calc_bias (BIASCOR) ADD_SCAN (add_scan_1c) - Adds together two scan 'core' files BIASPREP (cycle_bias_prep_1c) - Accumulates stats from feedback files BIASSELE (cycle_bias_sele_1c) - Selects data for bias correction BIASCOR (calc_bias_1c) - Calculates spatially varying bias correction coefficients BIASCONV (bias_conv_1c) - Combines reg and scan bias files from rtovs /atovs to a bcor.dat CYCLE_SCAN (cycle_scan_1c) - Calculates scan bias correction CALC_SCAN (calc_scan_1c) - Calculates scan bias correction CYCLE_BIAS (cycle_bias_1c) - Calculates spatially varying bias correction coefficients !!! The NAG routines were changed (computation of the eigenvalues and eigenvectors in regress_one.F90 – jacobi + eigsrt from Numerical Recipes)

14 Exercises 1a,b- compute a bcor file with 3 predictors max 30 (a) and 90 (b) scan angles a) NOAA16 only b) NOAA17 only 2a,b- compute a bcor file with 2 predictors max 30 (a) and 90 (b) scan angles

15 THE END !!!


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