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• The objective of this example is to demonstrate how to iterate efficiently over all the available hindcastYears, hindcastMonths and hindcastDays for a BoM reforecast request
• It 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 BoM reforecast. Don't forget to check BoM availability

 Please note:

• the most efficient way is to request all hindcastDates of a hindcastMonth hindcastMonthe, in one request, like the example below.
• you can use the variable target to write the requested data as you wish. In the example below the data is written per leveltype (sfc, pl) per hindcastMonth.
  

#!/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 = list(range([1, 27, 5))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)
            
            #Step 4: Get all the available perturbed forecast, pressure level data
            pfplTarget = "%s_%s_%04d%02d.grb" % (
                origin, "pfpl", hindcastYear, hindcastMonth)
            BoM_reforecast_cfpf_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_cfpf_sfc_request("/".join(hindcastDates), pfsfcTarget)


def BoM_reforecast_cfpf_pl_request(hindcastDate, target):
    """
       A BoM reforecast, controlperturbed 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/1488/by/24",
        "stream": "enfh",
        "target": target,
        "time": "00",
        "number": "1/to/32",
        "type": "pf",
    })


def BoM_reforecast_cfpf_sfc_request(hindcastDate, target):
    """
       A BoM reforecast, controlperturbed 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()