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UNDER CONSTRUCTION!!!

How is the TIGGE data organised in MARS?

In general it is organised, as a huge tree, with the indentation below, showing different levels down that tree:

Best practise to iterate over all  dates and all times for for a particular level type (eg Pressure levels)

(lightbulb) The best approach is to iterate over the dates and for each date iterate over the times.

(warning) At this point you may wish to  check TIGGE availability.

for date in dates
    for time in times      
        TIGGE-request(date, time)
        (Here you must add everything you need)

Web-API examples:

A TIGGE request for some dates

  • The objective of this example is to demonstrate how to iterate efficiently over some dates (eg '2014-10-01' and '2014-11-01')  a request  for 'perturbed forecast', 'pressure' and 'sfc' level, for TIGGE, ECMWF Center.
  • It can be used as a starting point, however you need to keep in mind that you have to adapt it to your needs eg to set the keyword values according to your requirements ('param', 'levtype', 'step' etc).
  • In this way you can extend this request to download a longer period of TIGGE.

(thumbs up) Keep in mind that the most efficient way to organise your requests is per dates and times

ie select a set of dates and times and add,  the 'steps', 'origins', 'levels' and 'parameters' that you need.

(thumbs down)   It is not efficient to organise your requests per parameter, per  origin  or per step. (eg to submit a different request per parameter for a list of dates)

#!/usr/bin/env python
from ecmwfapi import ECMWFDataServer
server = ECMWFDataServer()
   
def retrieve_tigge_data():
    dates = ['2014-10-01', '2014-11-01']
    times = ['00', '12']
    for date in dates:
         for time in times:
             target = 'ecmwf_sfc_%s_%s.grb' % (date, time)
             tigge_pf_sfc_request(date, time, target)
             target = 'ecmwf_pl_%s_%s.grb' % (date, time)
             tigge_pf_pl_request(date, time, target)

def tigge_pf_pl_request(date, time, target):
    '''
       A TIGGE request for perturbed forecast, pressure level, ECMWF Center.
       Please note that a subset of the available data is requested below.
       The cost of this request is xxx fields and xxx GB
       Change the keywords below to adapt it to your needs. (ie to add more parameters, or numbers etc)
    '''
    server.retrieve({
        'class': 'ti',
        'dataset': 'tigge',
        'date': date,
        'expver': 'prod',
        'grid': '0.5/0.5',
        'levelist': '200/250/300/500/',
        'levtype': 'pl',
        'number': '1/TO/10',
        'origin': 'ecmf',
        'param': '130/131/132/133',
        'step': '0/TO/96/BY/12',
        'target': target,
        'time': time,
        'type': 'pf',
    })

def tigge_pf_sfc_request(date, time, target):
    '''
       A TIGGE request for perturbed forecast, sfc, ECMWF Center.
       Please note that a subset of the available data is requested below.
       The cost of this request is xxx fields and xxx GB
       Change the keywords below to adapt it to your needs. (ie to add more parameters, or numbers etc)
    '''
    server.retrieve({
         'class': 'ti',
         'dataset': 'tigge',
         'date': date,
         'expver': 'prod',
         'grid': '0.5/0.5',
         'levtype': 'sfc',
         'number': '1/TO/10',
         'origin': 'ecmf',
         'param': '146/147/151/165/166/167/168/176/177',
         'step': '0/TO/96/BY/12',
         'target': target,
         'time': time,
         'type': 'pf',
       })

if __name__ == '__main__':
    retrieve_tigge_data()

 

Useful links

 

 




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