GFS Forecasts - Web service USAGE

Last update: June 2017 Back to Web service >>

    IntroductionInputs - Outputs

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Introduction

The Global Forecast System (GFS) is a weather forecast model produced by the National Centers for Environmental Prediction (NCEP). Dozens of atmospheric and land-soil variables are available worldwide, among which we selected a few parameters as listed in "output variables". This service delivers the most recent spatial resolution of 0.25°, corresponding approximately to 28 km. The data are available from about a month ago up to day+3.

The manual access via the Web service interface is for free and unlimited. We also provide an automatic access to the data, but this service is for pay. Please contact us for a quotation. All the information to build GFS forecasts automatic commands.

How are built the 3 hour original dataset?
The GFS archive 0.5° model Cycle Runtime (CR) is 0 h, 6 h, 12 h, and 18 h. Are also provided to the users the forecasts computed at CR+3 h to finally deliver time series with a 3 hour time step.
For the current day, the most recent computed CR and the corresponding CR + 3 h will be given. Afterwards, only 3 h forecasts will be given.

Inputs

  • Latitude and longitude: enter the values in decimal degrees (we advise 3 or 4 digits after comma), or directly click on the map to select your point, or you can also use the "Search Address" tool on the top of the map.
  • Start date and End date: format yyyy-mm-dd. MERRA-2 data are available from Jan. 1980 and are regularly updated but available with approx. a month of delay.
    Please pay attention to ask for complete months when asking for monthly values. If incomplete, the given monthly value results from an interpolation based on the selected days.
  • Time step: "1 min", "5 min", "10 min", "15 min", "30 min", "hour", "day", "week", or "month". NB: "1 min" and "5 min" time steps are limited to one month of data per delivery. Original time step of the data is 3 hours.
  • Output format: CSV only

Outputs

The output file format is CSV. When pushing the "process" button, wait a while and right-click on the appeared link to retrieve your file. Here is the output column content:

  • Temperature (K): temperature at 2 m above ground in Kelvins (K)
  • Relative humidity (%): Relative humidity at 2 m above ground in percent (%)
  • Pressure (hPa): Pressure at ground level in hPa
  • Wind speed (m/s): Wind speed at 10 m above ground in m/s
  • Wind direction (deg): Wind direction at 10 m above ground in degrees (0 means from North, 90 from East...)
  • Rainfall (kg/m2): Rainfall (= rain depth in mm)
  • Snowfall (kg/m2): Snowfall
  • Snow depth (m): Snow depth in meters
  • Short-wave irradiation (wh/m2): Surface downward short-wave irradiation (broadband=GHI)

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