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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

Keyworddefinition
dataset See Dataset section below.
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.
stepSpecifies 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"

Datasets

To access these datasets, you need to agree on the corresponding terms and conditions that can be found under the "Licence" link in the table below.

Catalogues can be found in http://apps.ecmwf.int/datasets

DatasetDescriptionLicenceCatalogueAbout
era15ECMWF Global Reanalysis Data - ERA-15 (Jan 1979 - Dec 1993)generalhttp://apps.ecmwf.int/datasets/data/era15era15
era20cReanalysis of the 20th-century using surface observations only (Jan 1900 - Dec 2010):generalhttp://apps.ecmwf.int/datasets/data/era20c_dailyera20c
era20cmv0ERA-20CM: Ensemble of climate model integrations (Experimental version)generalhttp://apps.ecmwf.int/datasets/data/era20cmv0_edmmera20cmv
era40ECMWF Global Reanalysis Data - ERA-40 (Sep 1957 - Aug 2002)generalhttp://apps.ecmwf.int/datasets/data/era40_dailyera40
eraclimERA-20CM: Ensemble of climate model integrationsgeneralComing soon... 
icoadsICOADS v2.5.1 with interpolated 20CR feedbackgeneralhttp://apps.ecmwf.int/datasets/data/icoadsicoads
interimECMWF Global Reanalysis Data - ERA Interim (Jan 1979 - present)generalhttp://apps.ecmwf.int/datasets/data/interim_full_dailyinterim
ispdISPD v2.2generalhttp://apps.ecmwf.int/datasets/data/ispdispd
maccMACCmacchttp://apps.ecmwf.int/datasets/data/macc_reanalysis 
macc_nrealtimeMACC Near Real-timemacc_nrealtimehttp://apps.ecmwf.int/datasets/data/macc_nrealtime/ 
tiggeTIGGE (THORPEX Interactive Grand Global Ensemble)tiggehttp://apps.ecmwf.int/datasets/data/tigge 
yotcYOTC (Year of Tropical Convection)generalhttp://apps.ecmwf.int/datasets/data/yotc_od 
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