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• The objective of this example is to demonstrate how to get efficiently all the available hincastDates for an ECMWF model version date.
• To start writing your request, firstly you 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 example to download the whole S2S ECMWF reforecast.

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

#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
origin = "ecmf"

# Step 1: Select a Model Version Date
modelVersionDate = "2015-12-03"

# Step 2: Set the hindcast Dates you wish to request
# For the model version "2015-12-03" the available hindcast dates are listed below:
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 retrieve efficiently all hindcastDates
       for a particular ECMWF reforecast model version.
       Change the variables below to adapt the request 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):
    """
       An ECMWF reforecast, perturbed forecast, pressure level, request.
       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):
    """
    An ECMWFreforecast, perturbed forecast, sfc request.
       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": 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()                                                          

• ECMWF re-forecast requests
• ECMWF Web API Home
• ECMWF re-forecast availability
• A brief description of reforecasts