MERRA automatic access

MERRA-2 automatic Access


 Automatic access is a charged service. Please contact us for a quotation

Automatic access to meteorological variables from MERRA-2 (NASA) resource. Even if MERRA-2 is accessible via a Web interface, we need to dimension our servers to welcome the large number of automatic requests. A fee is thus applied depending on the number of time series retrieved every day / year (subscription fee).

Please contact us for a quotation and receive your SoDa credentials.

Automatic access with WGET - Automatic access with CURL - FAQ

Download examples of scripts :   Unix                 Windows

Download WGET.EXE


Warning! It is strongly recommanded to avoid the launch of parallel requests, using the "&" at the end of each wget request line. This would endanger our system.

 Automatic access with WGET

  1. Download wget.exe in a directory (Windows environment - by default available in Unix)
  2. In the same directory, create a text file and copy-paste in a single line the following instruction to test this permanent access to Carpentras, France:

wget -O output.csv --header="soda-user: guest" --header="soda-passwd: guest" ...
",5.059&firstday=2017-01-01& ...

  1. Rename the text file with the .bat extension and double click on the .bat file to retrieve the output.csv output file (Windows environment). Rename the text file with a .sh extension and run it using > in a Unix environment.

  WGET, in details

wget -O output.csv --header="soda-user: your_login" --header="soda-passwd: your_password" ...
"https://server/pub/merra2_request.php?geopoint=latitude,longitude&firstday=yyyy-mm-dd ...


With (inputs):

  • your_login and your_password: this access is restricted to registered users, i.e. to users who purchased an automatic access to the data. Please contact us for a quotation or to receive your SoDa automatic access credentials 
  • server: by default, use our load balancer thanks to "". It will redirect your request on the fastest server available.
  • latitude and longitude: in degrees, with at least 3 digits after comma, e.g. "geopoint=45.563,7.25"
  • yyyy-mm-dd: the first day and last day of your request, from 1980 up to about a month ago. The available shortcuts to use for first and last days of the requests are: d, d-x, d+x, m, m-x, m+x, y, y-x, y+x with "x" representing numerical value, "d" = day, "m" = month, "y" = year
  • time_step: "1", "5", "10", "15" (minutes), "h" (hourly), "d" (daily), "m" (monthly). Automatic requests with a time step below 10 min are limited to one month, and automatic requests with a time step below one day limited to one year (identical to HelioClim-3 automatic request behavior).
  • output_format: optional. Possible values are standard formats "excel", "netcdf" and "json" or "unified" to get csv format. Default format is "unified".

Time reference is Universal Time.

Outputs: Identical to the output columns received via the MERRA-2 Web interface

Automatic access using CURL

You can also automatically retrieve MERRA-2 dataset by using the CURL command.
Beware the dates!!! MERRA data are available from 1985 up to a month ago.
Note that output csv files retrieved via the CURL command does not contain header.

Request (Windows):
curl -f -s -S -F stations=@stations.txt -o output.csv --header "soda-user: guest" --header "soda-passwd: guest"

With the following stations.txt file format:
# Columns:
# id: station name
# latitude and longitude: in degrees, with at least 3 digits after comma
# elevation: ignored
# time reference: ignored
# duration: "15" (minutes), "h" (hourly), "d" (daily) or "m" (monthly)
# firstday and lastday: first and the last days of the request, expressed as yyyy-mm-dd
# slope of panel: ignored
# azimuth of panel: ignored
# ground_albedo: ignored
# horizon: ignored (optional)
# calibration: ignored (optional)
# format: ignored (optional)
#id         lat    lon   elevation time duration firstday   lastday    slope azimuth albedo
Carpentras1 44.083 5.059 -999      UT   d        1985-01-01 1985-01-31 0     0       0.2
Carpentras2 44.083 5.059 -999      UT   h        1985-01-01 1985-01-05 0     0       0.2

NB: stations.txt is voluntarily identical to the one used to automatically retrieve satellite-derived solar radiation datasets HelioClim-3. Of course, a few parameters are not used to run this service but are needed for the CURL request.