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({ A "class": "s2", "dataset": "s2s", 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 = 1994 hindcastYearEnd "step": "0",= 2014 hindcastMonthStart = 1 "stream": "enfh", hindcastMonthEnd = 12 for hindcastYear "target": target,in list(range(hindcastYearStart, hindcastYearEnd + 1)): "time": "00", for hindcastMonth in list(range(hindcastMonthStart, hindcastMonthEnd + 1)): "type": "cf", }) hindcastYearList = ["2012", "2013"] hindcastMonthList = ["08", "09"] hindcastDayList = ["01", "02"] for hindcastYear in hindcastYearList: for hindcastMonth in hindcastMonthList: numberOfDays = calendar.monthrange(hindcastYear, hindcastMonth)[1] for hindcastDay in list(range(numberOfDays)): hindcastDate for= hindcastDay'%04d%02d%02d' in% hindcastDayList:( hindcastDate = hindcastYear, +hindcastMonth, hindcastMonthhindcastDay + hindcastDay1) retrieve_data(hindcastDate) | ||||
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for hindcastYear in ["2012", "2013"]: target = "%s%s.grb" % (origin, hindcastDate) for hindcastMonth in ["08", "09"]: cma_reforecast_request(hindcastDate, target) def cma_reforecast_request(hindcastDate, target): """ A CMA if hindcastMonth in ["01", "03", "05", "07", "08", "10", "12"]: hindcastDateEnd = "31" if hindcastMonth in [ "04", "06", "09", "11"]: hindcastDateEnd = "30"reforecast request. Change the keywords below to adapt it to your needs. """ server.retrieve({ "class": "s2", "dataset": "s2s", "date": modelVersionDate, for hindcastDay in ["01" ... hindcastDateEnd ]:"expver": "prod", "hdate": hindcastDate, "levtype": "sfc", hindcastDate = hindcastYear+hindcastMonth+hindcastDay "origin": origin, retrieve_data(hindcastDate,"2014-05-01","babj") |
BoM example
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for hindcastYear in ["2012", "2013"]:"param": "165/166", "step": "24/to/1440/by/24", for hindcastMonth in ["08stream",: "09enfh"]:, for hindcastDay in ["01" "06" "11" "16" "21" "26"]: "target": target, "time": "00", "number": "1/2/3", hindcastDate = hindcastYear+hindcastMonth+hindcastDay"type": "pf", }) if __name__ == '__main__': retrieve_data(hindcastDate,"2014-01-01","ammc"cma_reforecast() |
Useful links
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