Table of Contents
What is the objective of this page?
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To help users to improve S2S BoM 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 BoM
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for hindcastYear in hindcastYears |
Web-API examples:
A BoM reforecast request for one hindcastDate
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The request below is for all members of the perturbed forecast, for Geopotential height and temperature, for the pressure levels 500/700/850/925/1000, for time-steps 24/to/720/by/24 and for model version 2014-01-01 |
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#!/usr/bin/env python from ecmwfapi import ECMWFDataServer modelVersionDate = "2014-01-01" # This is the first model version for BoM (babj) hindcastDate = "2013-09-01" # The selected hindcast date server = ECMWFDataServer() server.retrieve({ "class": "s2", "dataset": "s2s", "date": modelVersionDate, "expver": "prod", "hdate": hindcastDate, "levtype": "pl", "levelist": "500/700/850/925/1000", "origin": "ammc", "param": "130/156", "step": "24/to/720/by/24", "stream": "enfh", "target": "data.pf.sfc", "time": "00", "number": "1/2/3", "type": "pf", }) |
A BoM reforecast request for all the available hindcastDates
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#!/usr/bin/env python import calendar from ecmwfapi import ECMWFDataServer server = ECMWFDataServer() def retrieve_BoM_reforecast(): ''' A function to demonstrate how to iterate efficiently over all hincastYears, hincastMonths etc ''' hindcastYearStart = 1981 hindcastYearEnd = 2013 hindcastMonthStart = 1 hindcastMonthEnd = 12 hincastDatesList = ["01", "06", "11", "21", "26"] for hindcastYear in list(range(hindcastYearStart, hindcastYearEnd + 1)): for hindcastMonth in list(range(hindcastMonthStart, hindcastMonthEnd + 1)): numberOfDays = calendar.monthrange(hindcastYear, hindcastMonth)[1] for hindcastDay in hincastDatesList: hindcastDate = '%04d%02d%s' % ( hindcastYear, hindcastMonth, hindcastDay) BoM_reforecast_request(hindcastDate) def BoM_reforecast_request(hindcastDate): ''' A BoM reforecast requests. Change the keywords below to adapt it to your needs. ''' modelVersionDate = "2014-05-01" target = "data_s2s_%s.grb" % (hindcastDate) server.retrieve({ "class": "s2", "dataset": "s2s", "date": modelVersionDate, "expver": "prod", "hdate": hindcastDate, "levtype": "pl", "levelist": "500/700/850/925/1000", "origin": "ammc", "param": "130/156", "step": "24/to/720/by/24", "stream": "enfh", "target": "data.pf.sfc", "time": "00", "number": "1/2/3", "type": "pf", }) if __name__ == '__main__': retrieve_BoM_reforecast() |
Useful links
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