Piggy_Packages V2026.1 帮助文档（七）WRFDA同化试验

数值天气预报的主要误差来源于初始场的误差。资料同化Data Assimilation是一种将观测资料与数值天气预报NWP产品及其各自的误差统计数据相结合的技术旨在为数值模式提供更加准确的初始场。在“Piggy_Packages V2026.1 帮助文档三WRF区域模式”中我们运行了48小时的区域模式预报现在我们想要在预报24小时之后同化当时的观测资料修正模式初始场再往后预报。首先我们回到Home目录创建一个名称为Case5的目录并进入。将WRFDA拷贝进来进入var/da目录。cd mkdir -p Case5 cd Case5 cp -r /pp_model/WRF-4.7.1/WRFDA . cd WRFDA/var/da将之前运行好的2026年3月30日00时的预报资料链接到当前目录命名为fgln -s ~/Case1/WRF-Real/run/wrfout_d01_2026-03-30_00:00:00 fg下载2026年3月30日00时的观测资料wget https://osdf-director.osg-htc.org/ncar/gdex/d337000/prep48h/2026/prepbufr.gdas.20260330.t00z.nr.48h* 如遇到网络问题可以输入以下命令获取备用链接echo 572R55uY5LiL6L295Zyw5Z2A77yaaHR0cHM6Ly9wYW4uYmFpZHUuY29tL3MvMXRzdk9EcHVHRzV3RVREeVlVbkFQU1E/cHdkPTEyMzQ | base64 --decode echo 虽然WRFDA支持直接读取prepbufr格式的观测资料但是本文作为演示目的将prepbufr格式的观测资料转换为little_r格式。ln -s prepbufr.gdas.20260330.t00z.nr.48h bufrfile prepbufr2littleR mv prepbufr2littleR.txt obs.2026033000切换到obsproc目录新建namelist.obsproc文件cd ../obsproc touch namelist.obsproc open -e namelist.obsproc粘贴下方内容record1obs_gts_filename ../da/obs.2026033000,obs_err_filename obserr.txt,gts_from_mmm_archive .true.,/record2time_window_min 2026-03-29_21:00:00,time_analysis 2026-03-30_00:00:00,time_window_max 2026-03-30_03:00:00,/record3max_number_of_obs 400000,fatal_if_exceed_max_obs .TRUE.,/record4qc_test_vert_consistency .TRUE.,qc_test_convective_adj .TRUE.,qc_test_above_lid .TRUE.,remove_above_lid .false.,domain_check_h .true.,Thining_SATOB .false.,Thining_SSMI .false.,Thining_QSCAT .false.,calc_psfc_from_qnh .true.,/record5print_gts_read .TRUE.,print_gpspw_read .TRUE.,print_recoverp .TRUE.,print_duplicate_loc .TRUE.,print_duplicate_time .TRUE.,print_recoverh .TRUE.,print_qc_vert .TRUE.,print_qc_conv .TRUE.,print_qc_lid .TRUE.,print_uncomplete .TRUE.,/record6ptop 1000.0,base_pres 100000.0,base_temp 290.0,base_lapse 50.0,base_strat_temp 215.0,base_tropo_pres 20000.0/record7IPROJ 1,PHIC 30,XLONC 110,TRUELAT1 20,TRUELAT2 50,MOAD_CEN_LAT 30,STANDARD_LON 110,/record8IDD 1,MAXNES 1,NESTIX 50, 200, 136, 181, 211,NESTJX 50, 200, 181, 196, 211,DIS 81, 10., 3.3, 1.1, 1.1,NUMC 1, 1, 2, 3, 4,NESTI 1, 40, 28, 35, 45,NESTJ 1, 60, 25, 65, 55,/record9PREPBUFR_OUTPUT_FILENAME prepbufr_output_filename,PREPBUFR_TABLE_FILENAME prepbufr_table_filename,OUTPUT_OB_FORMAT 2use_for 3DVAR,num_slots_past 3,num_slots_ahead 3,write_synop .true.,write_ship .true.,write_metar .true.,write_buoy .true.,write_pilot .true.,write_sound .true.,write_amdar .true.,write_satem .true.,write_satob .true.,write_airep .true.,write_gpspw .true.,write_gpsztd .true.,write_gpsref .true.,write_gpseph .true.,write_ssmt1 .true.,write_ssmt2 .true.,write_ssmi .true.,write_tovs .true.,write_qscat .true.,write_profl .true.,write_bogus .true.,write_airs .true.,/运行obsproc./obsproc.exe运行后将会生成 obs_gts_2026-03-30_00:00:00.3DVAR回到刚刚的目录将该文件链接过来命名为ob.ascii同时将be.dat和LANDUSE.TBL链接过来新建namelist.input并编辑cd ../da ln -s ../obsproc/obs_gts_2026-03-30_00:00:00.3DVAR ob.ascii ln -s ../run/be.dat.cv3 be.dat ln -s ~/Case1/WRF-Real/run/LANDUSE.TBL . touch namelist.input open -e namelist.input粘贴以下内容wrfvar1var4d .false.,print_detail_grad .false.,/wrfvar2analysis_accu 900,/wrfvar3ob_format 2,/wrfvar4/wrfvar5check_max_iv .true.,/wrfvar6max_ext_its 1,ntmax 50,orthonorm_gradient .true.,/wrfvar7cv_options 3,/wrfvar11/wrfvar18analysis_date 2026-03-30_00:00:00.0000,/wrfvar21time_window_min 2026-03-29_21:00:00.0000,/wrfvar22time_window_max 2026-03-30_03:00:00.0000,/time_controlstart_year 2026,start_month 03,start_day 30,start_hour 00,end_year 2026,end_month 03,end_day 30,end_hour 00,/domainse_we 50,e_sn 50,e_vert 48,dx 81000,dy 81000,/physicsphysics_suite CONUSmp_physics -1,cu_physics -1,ra_lw_physics -1,ra_sw_physics -1,bl_pbl_physics -1,sf_sfclay_physics -1,sf_surface_physics -1,num_land_cat 21,/dynamicshybrid_opt 2,base_temp 290.,/bdy_controlspec_bdy_width 5,specified .true.,/namelist_quiltnio_tasks_per_group 0,nio_groups 1,/运行WRFDA :mpirun -np 4 ./da_wrfvar.exe运行成功后将会生成wrfvar_output是同化后的结果文件。输入下方命令查看同化增量统计数据open -e gts_omb_oma_01 statistics计算并可视化同化增量cdo sub wrfvar_output fg analysis_increment.nc Panoply analysis_increment.nc注意地面变量如T2、U10、V10为诊断变量在WRF预报时才会更新同化时不会改变这些量。