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 all 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_reforecast():
"""
A function to demonstrate how to iterate efficiently over all hindcastYears, hindcastMonths etc
for a particular cma_reforecast_request.
Change the variables below to adapt the iteration to your needs
"""
hindcastYearStart = 1994
hindcastYearEnd = 2014
hindcastMonthStart = 1
hindcastMonthEnd = 12
for hindcastYear in list(range(hindcastYearStart, hindcastYearEnd + 1)):
for hindcastMonth in list(range(hindcastMonthStart, hindcastMonthEnd + 1)):
numberOfDays = calendar.monthrange(hindcastYear, hindcastMonth)[1]
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Table of Contents
This page is under construction!
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To help users to improve S2S CMA MARS requests performance via the WebAPI
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How the S2S data is organised in general 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 (CMA, ECMWF, NCEP, JMA, ...)
- realtime or reforecast
- type of data (control forecast or perturbed forecast)
- type of level (single level or pressure level or potential temperature)
- HindcastDates (2014-01-01 or 2014-01-02 or 2014-01-03, ...)
- time-steps
- members (for perturbed forecast)
- levels (for pl or pt)
- parameters
- levels (for pl or pt)
- members (for perturbed forecast)
- time-steps
- HindcastDates (2014-01-01 or 2014-01-02 or 2014-01-03, ...)
- 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 CMA request?
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for HindcastDate in HindcastDate-list (eg, 2010-03-01 to 2010-03-31) |
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 S2S-request(HindcastDate) |
An example to request Control forecast, single level, for HindcastYears 2010 to 2014 for 2 HindcastMonths (eg April and June)
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for each HindcastYear from 2010 to 2014 for HindcastMonth in 04, 06 for HindcastDay in HindcastMonthhindcastDay in list(range(numberOfDays)): hindcastDate = '%04d%02d%02d' % ( hindcastYear, hindcastMonth, hindcastDay + 1) HindcastDatetarget = HindcastYear-HindcastMonth-HindcastDay "%s%s.grb" % (origin, hindcastDate) S2S-cma_reforecast_request(HindcastDate) |
#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
server.retrieve({
"class": "s2",
"dataset": "s2s",
"date": "2014-05-01",
"expver": "prod",
"hdate": "2006-06-08/2007-06-08/2008-06-08/2009-06-08/2010-06-08/2011-06-08/2012-06-08/2013-06-08",
"levtype": "sfc",
"origin": "babj",
"param": "165",
"step": "0",
"stream": "enfh",
"target": "CHANGEME",
"time": "00",
"type": "cf",
})
hindcastDate, target)
def cma_reforecast_request(hindcastDate, target):
"""
A CMA reforecast request. 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": "165/166",
"step": "24/to/1440/by/24",
"stream": "enfh",
"target": target,
"time": "00",
"number": "1/2/3",
"type": "pf",
})
if __name__ == '__main__':
retrieve_cma_reforecast() |
Useful links
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