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Observation pre-processing in the ARPEGE/ALADIN model

Observation pre-processing in the ARPEGE/ALADIN model. Roger Randriamampianina Hungarian Meteorological Service ALADIN 3D-Var/ODB training course, Budapest, 6-10 June, 2006. Outline. Local pre-processing:. OULAN. BATOR. 1C RAD. BIAS CORRECTION.

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Observation pre-processing in the ARPEGE/ALADIN model

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

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

  3. Rad 1C BIAS CORRECTION

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

  5. BIAS COEFFICIENTS ….. 29 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 30 -0.00164026 -0.00227708 0.03135224 -0.03784703 27.62663388 31 -0.00008955 -0.00014095 -0.02659488 0.00765495 9.25367644 32 0.00145617 0.00153541 -0.00106764 -0.00033522 -26.54361135 33 -0.00077763 -0.00081683 -0.01119977 0.00471600 17.11752563 34 -0.00125565 -0.00123589 -0.00223703 0.00580792 22.64516041 35 -0.00222918 -0.00202333 0.00778655 0.00553262 35.73116973 36 -0.00164826 -0.00162834 0.00102069 0.00188357 28.99646870 37 0.00111741 0.00125730 0.00442148 0.00173871 -23.16951064 38 0.00316035 0.00373096 0.01763869 0.00919846 -68.29874750 39 0.00126843 0.00200747 0.02091688 0.01752808 -37.85648733 40 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 41 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 42 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 43 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 44 0.00233907 -0.00043594 -0.09607026 -0.08755920 13.14093337 45 -0.00362408 -0.00148748 0.02399263 0.09450759 36.39598276 46 0.00422673 0.00547714 0.00463669 0.06497542 -89.83165724 47 0.00529782 0.00556190 -0.08293150 0.06430759 -75.81235550

  6. Bias correction procedure – changing the predictors getpred.F90 ! Convert all temperatures to virtual temperatures tv(:,JPF) = temp(:,JPF)/(1.0 - 0.6*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))

  7. Bias correction procedure script • We need the (radiance) observation departures after screening (ECMA) /operativ/aladin/workdir/assim/bcorr • 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 OWNER=wshop01 ; export OWNER USER=wshop01 ; export USER CLASS=mf ; export CLASS EXPVER=J1C ; export EXPVER EXPNAME=SUBFU INITIME=2006051500 ; export INITIME BASETIME=2006051500 LASTDATE=2006052518 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)

  8. 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 206 206 207 207 208 208 # List of satellites to extract set -A NOAAID 15 15 16 16 17 17 # METEOSAT/NOAA/DMSP numbers set -A SENSOR 3 4 3 4 3 4 # 0=HIRS/MET,1=MSU,2=SSU,3=AMSU,6=SSM/I set -A NBCHAN 15 5 15 5 15 5 # no. of channels to be read set -A NY 8 4 10 4 10 4 # channels used and land/sea channel mask set -A USE_SAT 1 1 1 1 0 1 # Set to 1 to process satellite, 0 to skip set -A HOURLY 0 0 0 0 0 0 # 0/1 : evaluations in 6h/1h slots set -A MONITORING 0 0 0 0 0 0 # 0/1 : do monitoring set -A SCANNUM 30 90 30 90 30 90 # Number of scan positions set -A RMASK 1 1 1 1 1 1 # Use of radiosonde mask 1 yes, 0 no set -A SCORR 1 1 1 1 1 1 # Use of scan correction 1 yes, 0 no set -A NEIGN 444444 # Number of eigenvectors 4 tovs 3 ssmi set -A NPRED 4 4 4 4 4 4 # Number of predictors 6 tovs 4 ssmi Please check the other following variables/settings …

  9. 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

  10. 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) • ~{user}/Preproc/bcorr  9 executables (9 Makefiles) • (2) ~{user}/Preproc/bcorr/full_grid  9 executables !!! The NAG routines were changed (computation of the eigenvalues and eigenvectors in regress_one.F90 – jacobi + eigsrt from Numerical Recipes) 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

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

  12. THE END !!!

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