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This is a brief introduction of the main request parameter syntax of MARS. For further information/features, please refer to: Request 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.

Request 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 temprerature

Retrieve example:

retrieve,
 class = od,
 stream = oper,
 expver = 1,
 date = -3,
 time = 12,
 type = analysis,
 levtype = model levels,
 levelist = 1/to/137,
 param = temperature,
 grid = 2.5/2.5,
 target = “analysis”

Keyword exaplanation:

Keyworddefinition
Identification of archive
class

ECMWF classification to the given data:

  • Operations (od)
  • Research experiments (rd)
  • Re-Analysis datasets (e4 for ERA-40, er for ERA-15)
  • European Climate Network Support (cs)
  • DEMETER project (dm)
stream
Identifies the forecasting system used to generated the data when the same meteorological types are
archived.
  • oper is used for the Operational Atmospheric model
  • wave for the Wave model
Both models produce Analysis and Forecast data types.
expverVersion of the experiment. Each experiment is assigned a unique code version.
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)
levelistLevels for the specified levtype. (off if levtype=sfc)
param

Meteorological parameter. (t, temprerature, 130, 30.128, ...)

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 = "/scratch/ms/gid/analysis.grb"
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