Best practise to iterate over all hindcastDates of several hindcastYears for BoM
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The best approach is to iterate over the hindcastYears. 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:
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 5 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
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Table of Contents
*************** This page is under construction! *****************
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 the S2S data is 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:
- centre (BoM)
- realtime or reforecast
- type of data (control forecast or perturbed forecast)
- type of level (single level or pressure level or potential temperature)
- HindcastDates (2013-01-01 or 2013-01-02 or 2013-01-03, ...)
- time-steps
- members (for perturbed forecast)
- levels (for pl )
- parameters
- levels (for pl )
- members (for perturbed forecast)
- time-steps
- HindcastDates (2013-01-01 or 2013-01-02 or 2013-01-03, ...)
- type of level (single level or pressure level or potential temperature)
- type of data (control forecast or perturbed forecast)
- realtime or reforecast
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What would be the natural way to group requests?
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Following the previous paragraph, the natural way to group requests would be:
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What is the best approach to loop over several HindcastDates for a BoM request?
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title | The main idea in brief: |
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What is the best approach to get all HindcastDays for several HindcastYears ?
The best approach is to iterate over the Hyears you wish. For each Hyear iterate over all Hmonths and for each Hmonth iterate over all its Hdays.
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for HindcastYear in HindcastYears |
An example to request Perturbed forecast, pl, for HindcastYears 2012 to 2013 for 2 HindcastMonths (eg August & September)
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for HindcastYear from 2012 to 2013 |
A Perturbed forecast, pl, S2S-request example
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#!/usr/bin/env python from ecmwfapi import ECMWFDataServer server = ECMWFDataServer() BoM_reforecast_pf_sfc_request("/".join(hindcastDates), pfsfcTarget) def BoM_reforecast_pf_pl_request(hindcastDate, target): """ A BoM reforecast, 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": "2014-01-01"modelVersionDate, "expver": "prod", "hdate": HindcastDatehindcastDate, (ie the selected HindcastDate eg"levtype": "2013-09-01pl"), "levelist": "10/50/100/200/300/500/700/850/925/1000", "origin": origin, "levtype "param": "130/131/132/133/135/156", "step": "pl24/to/1488/by/24", "originstream": "enfh", "ammctarget": target, "paramtime": "133/15600", "stepnumber": "24/48 1/to/32", "number": "1/2/3/4/5/"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": "CHANGEME00", "timenumber": "001/to/32", "type": "pf", }) if __name__ == '__main__': retrieve_BoM_reforecast() |
If the request is "small" you may request more HindcastDates in one go.
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Useful links
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