5-30-23 The gfs0p25 archive may be accessed by a ftp client or by a web browser: 1) If you want to use a ftp client, Windows PC users may use WinSCP, FileZilla, etc. that support passive mode. MacOS and Linux users may use the ftp command. Connect your ftp client to ftp.arl.noaa.gov using anonymous and your email address for the username and password, respectively and change directory to /archives/gfs0p25. Note if you are using multiple ftp connections, limit the number of concurrent connections equal to or less than two. Otherwise, your access to our ftp server may be blocked off. 2) If you are using a web browser, point it to https://www.ready.noaa.gov/data/archives/gfs0p25. It may take a few minutes or longer for the webpage to display. ________________________________________________________________________________ 7-22-19 Fixing the error in the precipitation is complete. On July 8, 2019, NCEP implemented the revised code to fix the error. For prior dates, corrected files were re-created. ======================================================================= readme_gfs0p25_info.txt ======================================================================= ARL started this archive on May 1, 2019 while NCEP operationally ran this in a "parallel" environment, that is, before the GFS.v15.1 (FV3) became operational on June 12, 2019. Soon after the implementation, it was discovered that the precipitation labeled TPPA (total accumulation) was TPP6 (6-hour accumulation). Files with the erroneous precipitation were moved to the subdirectory "bad_precipitation". These may be used to compare HYSPLIT output from the GFS.v15 to the GFS.v14 in /pub/archives/gfs0p25.v1, keeping aware of the precipitation issue. This (/pub/archives/gfs0p25) 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 horizontal resolution. Data: anonymous ftp to ftp.arl.noaa.gov and change directory to /archives/gfs0p25. This file: https://www.ready.noaa.gov/data/archives/gfs0p25/readme_gfs0p25_info.txt Missings: https://www.ready.noaa.gov/data/archives/gfs0p25/readme_gfs0p25_missings.txt Description of other archived data in this format for HYSPLIT: https://www.ready.noaa.gov/archives.php *********************************************************************** ----------------------------------------------------------------------- Data fields, 4-character identifier, units ----------------------------------------------------------------------- Surface or single level: PRSS hPa surface pressure 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 hr 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 SHGT m surface height 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 that NCEP processed into the HYSPLIT-compatible format. For each of NCEP's 00, 06, 12, and 18 UTC cycles, NOAA OAR ARL retrieves the HYSPLIT-compatible forecast file, extracts the 0-hour initialization and 3-hour forecast of successive forecasts to create daily archives files. 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 that hour. To minimize missings, with each cycle the complete forecast file is written to appropriate archive files, but it is overwritten with more current forecasts as they become available. ----------------------------------------------------------------------- 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 A list of missings and files with forecast hours greater than 3 is in the file 'readme_gfs0p25_missings.txt'. ----------------------------------------------------------------------- 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 ----------------------------------------------------------------------- ARL - Air Resources Laboratory NCEP - National Centers for Environmental Prediction NOAA - National Oceanic and Atmospheric Administration NWS - National Weather Service OAR - Office of Oceanic and Atmospheric Administration -----------------------------------------------------------------------