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:
Keyword | definition |
---|---|
Identification of archive | |
class | ECMWF classification to the given data:
|
stream | Identifies the forecasting system used to generated the data when the same meteorological types are archived.
Both models produce Analysis and Forecast data types. |
expver | Version 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
|
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.
|
levtype | Denotes type of level:
|
levelist | Levels 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 = "analysis.grb" |