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":

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

 #!/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

Keyword	definition
dataset	See Available Datasets
Date & Time
time	Base time (00, 06, 12 and 18) Observation time (HHMM or HH:MM: ie 09:30)
date	Specifies the Analysis date, the Forecast base date or Observations date. Formats Absolute as YYYY-MM-DD, YYYYMMDD. The day of the year can also be used: YYYY-DDD Relative as -n ; n is the number of days before today (i.e., -1 = yesterday ) Name of month (e.g. january for Climatology data) Operational monthly means are retrieved by setting day (DD) to 00.
step	Specifies the forecast time step from forecast base time. Valid values are hours (HH)
Fields
type	Determines the type of field to be retrieved: This keyword makes the selection between observations, images or fields, and it determines some of the valid remaining keywords of the request. Analysis (an) Forecast (fc) Perturbed Forecast (pf) Control Forecast (cf)
levtype	Denotes type of level: Model level (ml) Pressure level (pl) Surface (sfc) Potential vorticity (pv) Potential temperature (pt) Depth (dp)
param	Meteorological parameter. (t, temprerature, 130, 30.128, ...)
grid	Output grid mesh Latitude/longitude increments in degrees (2.5/2.5) Number of latitude lines from Pole to Equator (160)
Storage
target	specifies a Unix file into which data is to be written after retrieval or manipulation. Path names should always be enclosed in double quotes: target = "analysis.grb"