Introduction
This is a brief introduction of the main request parameter syntax of MARS. For further information/features, please refer to: Request syntax.Request syntax:.
Note |
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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
Code Block |
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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 tempreraturetemperature
Retrieve example from "View MARS request":
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sfc,
param=165.128/41.128,
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=2013-09-01/to/2013-09-30,
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Code Block |
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language | py |
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title | Python equivalence |
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| #!/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"
}) |
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Keyword
In the Dataset service there is an extra mandatory keyword called dataset which does not appear in normal MARS requests.
Keyword | definition |
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dataset | See Available Datasets |
format | You can add 'format' : "netcdf" to retrieve the data in NetCDF format. |
the other possible MARS keywords are explained in the MARS keywords documentation.
Keyword exaplanation:
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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)
...
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.
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Base time (00, 06, 12 and 18)
Observation time (HHMM or HH:MM: ie 09:30)
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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.
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