Page History

...

Info

The objective of this example is to demonstrate how to iterate efficiently over all the available hincastDates for an ECMWF model version date.
To start writing your request you firstly need to select a model version date and to find the corresponding Hindcast Dates. Please check ECMWF availability
Keep in mind that the ECMWF reforecast configuration is "on the fly". For more information read a brief description of reforecasts.
The requests below can be used as a starting point, however you need to keep in mind that you have to adapt it to your needseg to set the keyword values according to your requirements ("param", "levtype", "step" etc).
In this way you can extend this request to download the whole S2S ECMWF reforecast. Don't forget to check ECMWF availability

You can use the variable target to organise the requested data in files as you wish.

Code Block

language	py

 ##!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
origin = "ecmf"
modelVersionDate = "2015-12-03"
hindcastDates = ["1995-12-03", "1996-12-03", "1997-12-03", "1998-12-03", "1999-12-03", "2000-12-03",
                 "2001-12-03", "2002-12-03", "2003-12-03", "2004-12-03", "2005-12-03", "2006-12-03", "2007-12-03",
                 "2008-12-03", "2009-12-03", "2010-12-03", "2011-12-03", "2012-12-03", "2013-12-03", "2014-12-03"]

def retrieve_ECMWF_reforecast():
    """
       A function to demonstrate how to iterate efficiently over all hindcastDates
       for a particular ECMWF reforecast model version.
       Change the variables below to adapt the iteration to your needs
    """
    # Please note that the "sfc" and "pl" requests below could run in parallel
    # Step 1: Get pressure level data
    pfplTarget = "%s_%s_%s.grb" % (origin, "pfpl", modelVersionDate)
    ECMWF_reforecast_pf_pl_request("/".join(hindcastDates), pfplTarget)
    # Step 2: Get surface data
    pfsfcTarget = "%s_%s_%s.grb" % (origin, "pfsfc", modelVersionDate)
    ECMWF_reforecast_pf_sfc_request("/".join(hindcastDates), pfsfcTarget)

def ECMWF_reforecast_pf_pl_request(hindcastDate, target):
    """
       AAn ECMWF reforecast, perturbed forecast, pressure level, request.
       The cost of this request is fields and  Gbytes 
       Change the keywords below to adapt it to your needs. (eg to add or remove some steps or parameters etc)
    """
    server.retrieve({
        "class": "s2",
        "dataset": "s2s",
        "date": modelVersionDate,
        "expver": "prod",
        "hdate": hindcastDates,
        "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/768/by/24",
        "stream": "enfh",
        "target": target,
        "time": "00",
        "number": "1/2/3/4",
        "type": "pf",
    })
def ECMWF_reforecast_pf_sfc_request(hindcastDate, target):
    """
    AAn ECMWFreforecast, perturbed forecast, sfc request.
       TheChange costthe ofkeywords thisbelow requestto isadapt 383,040it fieldsto andyour 7needs.1 GB
(eg to add or remove some steps Changeor the keywords below to adapt it to your needs.parameters etc)
    """
    server.retrieve({
        "class": "s2",
        "dataset": "s2s",
        "date": modelVersionDate,
        "expver": "prod",
        "hdate": hindcastDate,
        "levtype": "sfc",
        "origin": origin,
        "param": "1/33/34/59/121/122/134/136/146/147/151/165/166/167/168/169/175/176/177/179/180/181/235",
        "step": "24/to/744/by/24",
        "stream": "enfh",
        "target": target,
        "time": "00",
        "number": "1/2/3/4",
        "type": "pf",
    })
if __name__ == '__main__':
    retrieve_ECMWF_reforecast()

...

Space shortcuts

Page tree

Versions Compared

Old Version 16

New Version 17

Key