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What is the best approach to get all hindcastDays for several HindcastYears ?

Info
titleThe main idea in brief:

(lightbulb) 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

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the available hindcastDays.

(warning) At this point you may wish to check CMA availability and to view a CMA request

Info
titleThe main idea in brief:
for HindcastYear in HindcastYears
    for hindcastMonth in hindcastMonths        
        for hindcastDay in hindcastDays             
            hindcastDate = HindcastYear-hindcastMonth-hindcastDay               
                S2S-request(hindcastDate)

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Code Block
languagepy
#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
modelVersionDate = "2014-05-01"
hindcastDate = "2014-04-01"  # The selected hindcast date
server = ECMWFDataServer()
server.retrieve({
    "class": "s2",
    "dataset": "s2s",
    "date": ModelVersionDate,
    "expver": "prod",
    "hdate": hindcastDate, 
    "levtype": "sfc",
    "origin": "babj",
    "param": "165",
    "step": "0",
    "stream": "enfh",
    "target": "data.cf.sfc",
    "time": "00",
    "type": "cf",
})
Info

(lightbulb) If the request is "small" you may request more hindcastDates in one go.

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See the example below.

A web API example requesting data for several hindcastDates (iterating over several hindcastYears, hindcastMonths and hindcastDays)

 

Info
  • The objective of this example is to demonstrate how to make a MARS request efficient by iterating properly. 
  • It can be used as a starting point however you need to adapt it to your needseg:
    • to set the keyword values (eg hindcastYear)  according to your needs. 

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(grey lightbulb) By setting the variable "target" accordingly you can have each hindcastDate to be written on a separate file .

Code Block
languagepy
#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
def retrieve_data(hindcastDate):
    target = "target_s2s_%s.grb" % hindcastDate
    server.retrieve({
       "class": "s2",
       "dataset": "s2s",
       "date": "2014-05-01",
       "expver": "prod",
       "hdate": hindcastDate,
       "levtype": "sfc",
       "origin": "babj",
       "param": "165",
       "step": "0",
       "stream": "enfh",
       "target": target,
       "time": "00",
       "type": "cf",
})

for hindcastYear in ["2012", "2013"]:
    for hindcastMonth in ["08", "09"]:
        for hindcastDay in ["01", "02"]:
            hindcastDate = hindcastYear+hindcastMonth+hindcastDay
            retrieve_data(hindcastDate)

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