======================================================================= readme_gfs0p25_info.txt 12 Jun 2019 ======================================================================= This (/pub/archives/gfs0p25.v1) terminated June 12, 2019 with NCEP's upgrade to GFS.v15.1 (FV3). For subsequent GFS output see /pub/archives/gfs0p25. ======================================================================= readme_gfs0p25_info.txt 09 Jan 2017 ======================================================================= Beginning January 9, 2017, forecast files from today's 00z 8-day GFS forecast will be written here to preemptively fill-in possible future missings. If available, the archive files consisting of only +0 and +3-h forecasts will overwrite these files later. Please read the forecast hour of the file if you must know if the data are the concatenated +0, +3-h forecasts, or a longer forecast. Clearly files with a date in the future in the filename are forecasts, not +0 +3 concatenations. From now on only true missings (no file at all for the day) will be listed in the file readme_gfs0p25_missings.txt. ======================================================================= readme_gfs0p25_info.txt 26 Jul 2017 ======================================================================= Effective beginning with the archive file 20170719_gdas0p5, (1) there is no vertical velocity, and (2) the data are short-term GFS forecasts instead of GDAS See https://hysplitbbs.arl.noaa.gov/viewtopic.php?f=7&t=1284 ======================================================================= readme_gfs0p25_info.txt 02 Dec 2016 ======================================================================= 1. Fields changed effective 20161201: 1a. added surface height (SHGT) 1b. replaced upper-level specific humidity (SPHU) with relative humidity (RELH) 2. Edited below: 2a. to show above changes 2b. for general clarification ======================================================================= readme_gfs0p25_info.txt ======================================================================= This is an archive of concatenated short-term NCEP Global Forecast System (GFS) forecast model output having a quarter-degree latitude-longitude grid on native model (hybrid) levels. The zero and three hour (+0, +3) forecasts from successive (6-hourly) GFS runs are concatenated to make the pseudo-analysis. 21 hours of model output are in a single file. Model output is at 3-hour intervals. Some 6-h forecast fields (e.g. precipitation) are at hour +0. The notation "0p25" means 0.25 degrees resolution. These files are created on an NCEP development-access computer which is sometimes unavailable because of maintenance or NCEP operations testing, or there may be other reasons which can cause files to be missing, Missings are filled as follows: (1) The 21-h f000 (+0) forecast is used to replace the concatenated file (2) The 'day 2' f024, 'day 3' f048, etc. forecast is used (3) Otherwise these are not able to be re-created, and the file is not available. Data: ftp://ftp.arl.noaa.gov/archives/gfs0p25/ This file: ftp://ftp.arl.noaa.gov/archives/gfs0p25/readme_gfs0p25_info.txt Missings: ftp://ftp.arl.noaa.gov/archives/gfs0p25/readme_gfs0p25_missings.txt. Description of other archived data in this format for HYSPLIT: http://www.ready.noaa.gov/archives.php *********************************************************************** ----------------------------------------------------------------------- Data fields, 4-character identifier, units ----------------------------------------------------------------------- Surface or single level: PRSS hPa surface pressure SHGT m surface height MSLE hPa mean sea level pressure UMOF N/m2 u-component of momentum flux VMOF N/m2 v-component of momentum flux TPP6 m precipitation, 6-hourly accumulation SHTF W/m2 sensible heat net flux DSWF W/m2 downward short wave radiation flux SPH2 kg/kg specific humidity at 2 meters AGL U10M m/s u wind component at 2 meters AGL V10M m/s v wind conponent at 2 meters AGL T02M K temperature at 2 meters AGL TCLD % total cloud cover PBLH m planetary boundary layer height LHTF W/m2 latent heat net flux USTR m/s friction velocity RGHS m surface roughness PTRO hPa pressure at the tropopause 3-dimensional: TEMP K temperature UWND m/s u wind component VWND m/s v wind component WWND hPa/h w wind component RELH % relative humidity PRES hPa pressure *********************************************************************** ----------------------------------------------------------------------- File creation ----------------------------------------------------------------------- NOAA NWS NCEP runs numerical weather prediction (NWP) models. This archive contains output from the NCEP GFS model (http://www.emc.ncep.noaa.gov/index.php?branch=GFS). NOAA OAR ARL processes the NCEP output into the HYSPLIT-compatible format. Since NCEP runs the GFS 4 times a day, at 00, 06, 12, and 18 UTC, each day's file is a concatenation of successive 0-hour initialization and 3-hour forecasts from the 4 daily runs. In addition some 6-hour forecast fields are written to the 0-hour valid times (00, 06, 12, 18 UTC) because they are not output by NCEP at the the 0-hour initialation time. ----------------------------------------------------------------------- These files are not created in a 24x7 operational environment. ----------------------------------------------------------------------- A missing file can result when ARL's processing job fails. Failures can be caused by computer outages, file transfer failures, or other reasons. If files are missing please use another dataset (e.g. reanalysis). See http://ready.arl.noaa.gov/archives.php ----------------------------------------------------------------------- 55 hybrid sigma-pressure Levels ----------------------------------------------------------------------- 0.9999, 0.9947, 0.9886, 0.9817, 0.9739, 1.9648, 1.9544, 2.9425, 4.9288, 6.9132, 8.8954, 11.875, 16.853, 21.827, 26.799, 33.769, 41.735, 49.699, 59.660, 69.619, 80.576, 91.531, 102.49, 113.44, 123.39, 133.35, 143.30, 151.26, 157.22, 162.18, 165.15, 166.12, 165.09, 162.07, 157.05, 150.04, 142.02, 132.01, 122.01, 111.00, 99.002, 88.000, 78.000, 68.000, 59.000, 52.000, 45.000, 39.000, 34.000, 29.000, 25.000, 21.000, 18.000, 15.000, 13.000 The pressure level is defined as: P = A + .B*PRSS, where PRSS is the surface pressure and A.B is defined as the level (ie., 16.853 = 869 hPa when the surface pressure is 1000 hPa [P=16+0.853*1000]) ----------------------------------------------------------------------- quarter-degree horizontal grid ----------------------------------------------------------------------- 1440 x 721 gridpoints ----------------------------------------------------------------------- Acronyms - Web sites ----------------------------------------------------------------------- ARL - Air Resources Laboratory - http://www.arl.noaa.gov/ NCEP - National Centers for Environmental Prediction - http://www.ncep.noaa.gov/ NOAA - National Oceanic and Atmospheric Administration - http://www.noaa.gov/ NWS - National Weather Service - http://www.weather.gov/ OAR - Office of Oceanic and Atmospheric Administration - http://www.oar.noaa.gov/ -----------------------------------------------------------------------