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 each hindcastYear iterate over all the available hindcastMonths and for each hindcastMonth iterate over all the available hindcastDays.
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for hindcastYear in hindcastYears |
Web-API examples
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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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language | py |
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A BoM reforecast request for all the available hindcastDates
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#!/usr/bin/env python from ecmwfapi import ECMWFDataServer server = ECMWFDataServer() origin = "ammc" modelVersionDate = "2014-01-01" def retrieve_BoM_reforecast(): """ A function to demonstrate how to iterate efficiently over all hindcastYears, hindcastMonths etc for a particular BoM_reforecast_request. Change the variables below to adapt the iteration to your needs """ hindcastYearStart = 1981 hindcastYearEnd = 2013 hindcastMonthStart = 1 hindcastMonthEnd = 12 # BoM availability is every hindcastDays5 = list(range(1, 27, 5)) # available every 5 days: days: 1, 6, 11, 16, 21, 26 hindcastDays = [1, 6, 11, 16, 21, 26] #Step 1: Iterate over all the available hindcastYear(s) for hindcastYear in list(range(hindcastYearStart, hindcastYearEnd + 1)): #Step 2: Iterate over all the available hindcastMonths(s) for hindcastMonth in list(range(hindcastMonthStart, hindcastMonthEnd + 1)): hindcastDates = [] #Step 3: Create the list of the available hindcastDates for hindcastDay in hindcastDays: hindcastDate = '%04d%02d%02d' % ( hindcastYear, hindcastMonth, hindcastDay) hindcastDates.append(hindcastDate) #Please note: the steps 4 and 5 below could run in parallel #Step 4: Get all the available perturbed forecast, pressure level data target pfplTarget = "%s%04d%02d%s_%s_%04d%02d.grb" % ( origin, "pfpl", hindcastYear, hindcastMonth) print BoM_reforecast_pf_pl_request("/".join(hindcastDates), pfplTarget) #Step 5: Get all the available perturbed forecast, surface data pfsfcTarget = "%s_%s_%04d%02d.grb" % ( origin, "pfsfc", hindcastYear, hindcastMonth) BoM_reforecast_pf_sfc_request("/".join(hindcastDates), targetpfsfcTarget) def BoM_reforecast_pf_pl_request(hindcastDate, target): """ A BoM reforecast requests., perturbed forecast, pressure level, request. The cost of this request is 571,392 fields and 11.1352 Gbytes Change the keywords below to adapt it to your needs. """ server.retrieve({ "class": "s2", "dataset": "s2s", "date": modelVersionDate, "expver": "prod", "hdate": hindcastDate, "levtype": "pl", "levelist": "10/50/100/200/300/500/700/850/925/1000", "origin": origin, "param": "130/131/132/133/135/156", "step": "24/to/7201488/by/24", "stream": "enfh", "target": target, "time": "00", "number": "1/to/32", "type": "pf", }) def BoM_reforecast_pf_sfc_request(hindcastDate, target): """ A BoM reforecast, perturbed forecast, sfc request. The cost of this request is 383,040 fields and 7.1 GB Change the keywords below to adapt it to your needs. """ server.retrieve({ "class": "s2", "dataset": "s2s", "date": modelVersionDate, "expver": "prod", "hdate": hindcastDate, "levtype": "sfc", "origin": origin, "param": "31/34/121/122/136/146/147/151/167/168/169/175/176/177/179/180/181/235/228086/228095/228096/228141/228143/228144/228164/228228", "step": "24/to/1488/by/24", "stream": "enfh", "target": target, "time": "00", "number": "1/to/32", "type": "pf", }) if __name__ == '__main__': retrieve_BoM_reforecast() |
Useful links
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