Table of Contents
What is the objective of this page?
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To help users to improve S2S CMA MARS requests performance via the WebAPI.
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How is the S2S reforecast data organised in MARS?
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In general it is organised, as a huge tree, with the indentation below, showing different levels down that tree:
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What would be the natural way to group requests?
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The idea is to request as much data as possible from the same tape file. The natural way to group requests would be:
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Best practise to iterate over all hindcastDates of several hindcastYears for CMA
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for hindcastYear in hindcastYears |
Web-API examples:
A CMA reforecast request for
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all
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#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
modelVersionDate = "2014-05-01" # This is the first model version for CMA (babj)
hindcastDate = "2014-04-01" # The selected hindcast date
server = ECMWFDataServer()
server.retrieve({
"class": "s2",
"dataset": "s2s",
"date": modelVersionDate,
"expver": "prod",
"hdate": hindcastDate,
"levtype": "sfc",
"origin": "babj",
"param": "165/166",
"step": "24/to/1440/by/24",
"stream": "enfh",
"target": "data.pf.sfc",
"time": "00",
"number": "1/2/3",
"type": "pf",
}) |
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the available hindcastDates
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Please note:
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#!/usr/bin/env python import calendar from ecmwfapi import ECMWFDataServer server = ECMWFDataServer() origin = "babj" modelVersionDate = "2014-05-01" def retrieve_cma_datareforecast(hindcastDate,modelVersionDate,centre): target = "target_s2s_%s_%s.grb""" % centre % hindcastDate server.retrieve({ "class": "s2", "dataset": "s2s", A function to demonstrate how to iterate efficiently over all hindcastYears, hindcastMonths etc "date": modelVersionDate, "expver": "prod", for a particular cma_reforecast_request. "hdate": hindcastDate, "levtype": "sfc", "origin": centre, Change the variables below to adapt the iteration to your needs "param": "165", hindcastYearStart "step": "0",= 1994 hindcastYearEnd "stream": "enfh",= 2014 hindcastMonthStart "target": target,= 1 hindcastMonthEnd "time": "00", = 12 "type": "cf", }) for hindcastYear in ["2012", "2013"]list(range(hindcastYearStart, hindcastYearEnd + 1)): for hindcastMonth in ["08", "09"]: for hindcastDayhindcastMonth in ["01" "02" ]list(range(hindcastMonthStart, hindcastMonthEnd + 1)): hindcastDatenumberOfDays = hindcastYear+hindcastMonth+hindcastDay calendar.monthrange(hindcastYear, hindcastMonth)[1] retrieve_data(hindcastDate,"2014-05-01","babj") |
v1.1
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#!/usr/bin/env python from ecmwfapi import ECMWFDataServer server = ECMWFDataServer() origin = "babj" modelVersionDate = "2014-05-01" hindcastYearList = ["2012", "2013"] hindcastMonthList = ["08", "09"] hindcastDayList = ["01", "02"] def retrieve_data(hindcastDate): target = "target_s2s_%s_%s.grb" % (origin, hindcastDate) server.retrieve({ "class": "s2",for hindcastDay in list(range(numberOfDays)): hindcastDate = '%04d%02d%02d' % ( hindcastYear, hindcastMonth, hindcastDay + 1) "dataset": "s2s", target = "date": modelVersionDate,%s%s.grb" % (origin, hindcastDate) "expver": "prod", "hdate": hindcastDate, cma_reforecast_request(hindcastDate, target) def cma_reforecast_request(hindcastDate, target): "levtype": "sfc", "origin": "babj", A CMA "param": "165", "step": "0", reforecast request. Change the keywords below to adapt it to your needs. "stream": "enfh", "target": target,server.retrieve({ "timeclass": "00s2", "typedataset": "cfs2s", }) def iterate(): for hindcastYear in hindcastYearList: for hindcastMonth in hindcastMonthList:"date": modelVersionDate, for hindcastDay in hindcastDayList: hindcastDate = hindcastYear + hindcastMonth + hindcastDay"expver": "prod", retrieve_data(hindcastDate) if __name__ == '__main__': iterate() |
v1.3
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for hindcastYear in ["2012", "2013"]:"hdate": hindcastDate, "levtype": "sfc", for hindcastMonth in ["08", "09origin"]: origin, if hindcastMonth in ["01", "03", "05", "07", "08", "10", "12"]: hindcastDateEnd = "31" if hindcastMonth in [ "04", "06", "09", "11"]: hindcastDateEnd = "30""param": "165/166", "step": "24/to/1440/by/24", "stream": "enfh", for hindcastDay in ["01" ... hindcastDateEnd ]: hindcastDate = hindcastYear+hindcastMonth+hindcastDay "target": target, retrieve_data(hindcastDate,"2014-05-01","babj") |
BoM example
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for hindcastYear in ["2012", "2013"]: "time": "00", for hindcastMonth in ["08number",: "09"]: 1/2/3", for hindcastDay in ["01type": "06pf", "11" "16" "21" "26"]: hindcastDate = hindcastYear+hindcastMonth+hindcastDay }) if __name__ == '__main__': retrieve_cma_data(hindcastDate,"2014-01-01","ammc"reforecast() |
Useful links
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