Introduction

This is a brief introduction of the main request parameter syntax.

We recommend that you get familiar with datasets and their availability using http://apps.ecmwf.int/datasets/

You can also get the request syntax using "View MARS request" feature.

Syntax

verb,
 keyword1 = value1,
      ... = value2,
 keywordN = valueN
  • verb: action to be taken (e.g. retrieve, list, read)
  • keyword: a known MARS variable, e.g. type or date
  • value: value assigned to the keyword, e.g. Analysis or temperature

Retrieve example from "View MARS request":

MARS request
retrieve,
 stream=oper,
 levtype=sfc,
 param=165.128/41.128,
 dataset=interim,
 step=0,
 grid=0.75/0.75,
 time=00,
 date=2013-09-01/to/2013-09-30,
 type=an,
 class=ei
Python equivalence
 #!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
   
server = ECMWFDataServer()
   
server.retrieve({
    'dataset' : "interim",
	'time'    : "00",
	'date'    : "2013-09-01/to/2013-09-30",
    'step'    : "0",
    'type'    : "an",
    'levtype' : "sfc",    
    'param'   : "165.128/41.128",
    'grid'    : "0.75/0.75",
    'target'  : "interim201309.grib"
    })

Keyword

In the Dataset service there is an extra mandatory keyword called dataset which does not appear in normal MARS requests.

Keyworddefinition
dataset See Available Datasets
formatYou can add 'format' : "netcdf" to retrieve the data in NetCDF format.

the other possible MARS keywords are explained in the MARS keywords documentation.