{"id":45116,"date":"2020-12-23T10:03:42","date_gmt":"2020-12-23T10:03:42","guid":{"rendered":"https:\/\/nwp-saf.eumetsat.int\/site\/?page_id=45116"},"modified":"2023-04-21T12:48:11","modified_gmt":"2023-04-21T12:48:11","slug":"use-of-amvs-in-the-ncep-model","status":"publish","type":"page","link":"https:\/\/nwp-saf.eumetsat.int\/site\/monitoring\/winds-quality-evaluation\/amv\/amv-use-in-nwp\/use-of-amvs-in-the-ncep-model\/","title":{"rendered":"Use of AMVs in the NCEP model"},"content":{"rendered":"<h2>Use of AMVs in the NCEP model<\/h2>\n\n<h3>Physical characteristics<\/h3>\n<ul>\n<li>FV3GFS model, non-hydrostatic, C768 (~13km deterministic) GFS Physics, GFDL Microphysics, FV3GDAS C384 (25km, 80 member ensemble)<\/li>\n<li>Horizontal resolution: C768 with gaussian grid 1760&#215;880<\/li>\n<li>Vertical resolution: 127 vertical layers with hybrid configuration from sigma level to isobaric pressure level, top at 0.2 hPa<\/li>\n<li>For more info on the FV3 dynamic code:  https:\/\/www.gfdl.noaa.gov\/fv3\/<\/li>\n<\/ul>\n<h3>Data assimilation method<\/h3>\n<ul>\n<li>Type: Hybrid 4DEnVar<\/li>\n<li>Time window: T \u00b1 3 hr, analysis times (T): 00, 06, 12, 18 Z\n<li>Time constraints (model runtime):<\/li>\n<li>Main forecast run: 14 min before time window ends<\/li>\n<li>Update run: 3 hr 50 min after time window ends\n<li>EnKF for ensemble perturbations\n<\/ul>\n<h3>AMV types assimilated<\/h3>\n<h4>Global Model<\/h4>\n<ul>\n<li>Meteosat-10 IR, VIS, cloudy WV\n<li>Meteosat-9 IR, VIS, cloudy WV\n<li>GOES-18 IR, cloudy WV, clear air WA\n<li>GOES-16 IR, cloudy WV, clear air WA\n<li>HIMAWARI-9 IR, VIS, cloudy WV\n<li>NESDIS Terra IR, cloudy WV, clear sky WV\n<li>NESDIS Aqua IR, cloudy WV, clear sky WV\n<li>NESDIS S-NPP and JPSS\/NOAA-20 VIIRS IR\n<li>NESDIS Metop-B and Metop-C AVHRR IR\n<li>NOAA-15\/18\/19 IR\n<li>LEOGEO IR\n<\/ul>\n<h3>Quality control<\/h3>\n<h4>Blacklisting in space<\/h4>\n<ul>\n<li>Zenith angle greater than 68 for satellite winds from geostationary satellites\n<li>Pressure level less than 125 hPa, or greater than 950 hPa\n<li>No visible data used if pressure level less than 700 hPa\n<li>Pressure level is 50 hPa above tropopause\n<li>NESDIDS IR and EUMETSAT IR between 800-400 hPa\n<li>JMA IR between 800-500 hPa removed\n<li>600-250 hPa for MODIS water vapor deep layer wind\n<li>Pressure below 600 hPa for MODIS water vapor cloud top wind\n<li>Height above 250 hPa for MODIS IR wind\n<li>IR winds over land\n<\/ul>\n<h4>QI thresholds<\/h4>\n<p>QI without forecast guess less than 85 for JMA and EUMETSAT winds, and less than 90 for NESDIS winds<\/p>\n<h4>Thinning<\/h4>\n<ul>\n<li>200(km)x200(km)x100mb box is used to thin Met-9, Met-10, Him-9 winds\n<\/ul>\n<h4>Background check<\/h4>\n<ul>\n<li>Gross check: C=vector difference (O-B)\/observation error, data rejected if C > gross check limit\n<li>Asymmetric gross check: data rejected if O-B speed < 0 and C > f * gross check limit\n<li>For GOES IR and water vapor cloud top winds, asymmetric gross check applies between 300-400 hPa\n<li>FOR EUMESAT IR winds, asymmetric gross check applies between 200-400 hPa\n<li>For MODIS winds asymmetric gross check applies all levels\n<li>Log-Normal Vector Difference check applied to Polar and GOES WVCA winds: C=vector difference (O-B)\/log(obs speed), data rejected of C > = 3\n<li>LNVD check also rejects winds over a non-ocean surface within 110 hPa (for GOES) or 200 hPa (Polar) of the surface\n<\/ul>\n<h3>Observation errors<\/h3>\n<table border=\"1\" cellspacing=\"0\" cellpadding=\"2\" align=\"center\">\n<tr>\n<td align=\"center\">Level (hPa)<\/p>\n<td align=\"center\">surf-750<\/p>\n<td align=\"center\">700-650<\/p>\n<td align=\"center\">600-550<\/p>\n<td align=\"center\">500<\/p>\n<td align=\"center\">450<\/p>\n<td align=\"center\">400<\/p>\n<td align=\"center\">350<\/p>\n<td align=\"center\">300<\/p>\n<td align=\"center\">250-top<br \/>\n<\/tr>\n<tr>\n<td align=\"center\">GOES, EUMETSAT, MODIS, JMA (IR, VIS) \/ Error (m\/s)<\/p>\n<td align=\"center\">3.8<\/p>\n<td align=\"center\">3.9<\/p>\n<td align=\"center\">4.0<\/p>\n<td align=\"center\">4.1<\/p>\n<td align=\"center\">5.0<\/p>\n<td align=\"center\">6.0<\/p>\n<td align=\"center\">6.3<\/p>\n<td align=\"center\">6.6<\/p>\n<td align=\"center\">7.0<br \/>\n<\/tr>\n<tr>\n<td align=\"center\">JMA (WV) \/ Error (m\/s)<\/p>\n<td align=\"center\">3.8<\/p>\n<td align=\"center\">3.9<\/p>\n<td align=\"center\">4.0<\/p>\n<td align=\"center\">4.1<\/p>\n<td align=\"center\">5.0<\/p>\n<td align=\"center\">7.0<\/p>\n<td align=\"center\">7.3<\/p>\n<td align=\"center\">7.6<\/p>\n<td align=\"center\">8.0<br \/>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p>Use of AMVs in the NCEP model Physical characteristics FV3GFS model, non-hydrostatic, C768 (~13km deterministic) GFS Physics, GFDL Microphysics, FV3GDAS C384 (25km, 80 member ensemble) Horizontal resolution: C768 with gaussian grid 1760&#215;880 Vertical resolution: 127 vertical layers with hybrid configuration from sigma level to isobaric pressure level, top at 0.2 hPa For more info on the FV3 dynamic code: https:\/\/www.gfdl.noaa.gov\/fv3\/ Data assimilation method Type: Hybrid 4DEnVar Time window: T \u00b1 3 hr, analysis times (T): 00, 06, 12, 18 Z Time constraints (model runtime): Main forecast run: 14 min before time window ends Update run: 3 hr 50 min after [&hellip;]<\/p>\n","protected":false},"author":25,"featured_media":0,"parent":1312,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"footnotes":""},"class_list":["post-45116","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/nwp-saf.eumetsat.int\/site\/wp-json\/wp\/v2\/pages\/45116","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nwp-saf.eumetsat.int\/site\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/nwp-saf.eumetsat.int\/site\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/nwp-saf.eumetsat.int\/site\/wp-json\/wp\/v2\/users\/25"}],"replies":[{"embeddable":true,"href":"https:\/\/nwp-saf.eumetsat.int\/site\/wp-json\/wp\/v2\/comments?post=45116"}],"version-history":[{"count":0,"href":"https:\/\/nwp-saf.eumetsat.int\/site\/wp-json\/wp\/v2\/pages\/45116\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/nwp-saf.eumetsat.int\/site\/wp-json\/wp\/v2\/pages\/1312"}],"wp:attachment":[{"href":"https:\/\/nwp-saf.eumetsat.int\/site\/wp-json\/wp\/v2\/media?parent=45116"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}