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How is the TIGGE data organised in MARS?
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In general it is organised, as a huge tree, with the indentation below, showing different levels down that tree: |
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The idea is to request as much data as possible from the same tape file. The natural way to group requests would be: Note the following:
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What would be the natural way to group requests?
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Best practise to iterate over
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all dates and all times for
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for a particular level type (eg Pressure levels)
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The idea is to request as much data as possible from the same tape file . The best approach is to iterate over the dates and for each date iterate over the times. At this point you may wish to check TIGGE availability and to view a TIGGE request. |
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for date in dates |
Web-API examples:
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Example 1: Two TIGGE requests (sfc and pl), for some dates, for the same 'origin'
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Keep in mind that the The most efficient way is to organise your requests is per dates and times ie select a set of 'dates' and 'times' and add, add the 'steps', 'origins', 'levels' and 'parameters' that you need. It is not efficient to organise your requests per parameter, per origin or or per step. (eg to submit a different request per parameter or per origin for a set list of datedates) |
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#!/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() |
Example 2: A TIGGE sfc request for some dates, for several 'origins'
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If you wish to download the same data for more than one origins it is more efficient to request all of them in one go.
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#!/usr/bin/env python from ecmwfapi import ECMWFDataServer server = ECMWFDataServer() def retrieve_tigge_data(): dates = ['2014-12-01', '2014-12-02'] times = ['00', '12'] for date in dates: for time in times: target = 'tigge_cf_sfc_%s_%s.grb' % (date, time) tigge_cf_sfc_request(date, time, target) def tigge_cf_sfc_request(date, time, target): ''' A TIGGE request for control forecast, sfc, for 3 origins : ECMWF, JMA and KMA. Keep in mind that if you wish to download the same data, for more than one origins, it is more efficient to request all of them in one go. You can change the keywords below to adapt it to your needs, (ie to add more parameters, or steps, or even more origins etc), Presumably you need to check the availability of the requested origins. ''' server.retrieve({ 'class': 'ti', 'dataset': 'tigge', 'date': date, 'expver': 'prod', 'grid': '0.5/0.5', 'levtype': 'sfc', 'origin': 'ecmf/rjtd/rksl', 'param': '167/168', 'step': '0/96/168', 'target': target, 'time': time, 'type': 'cf', }) if __name__ == '__main__': retrieve_tigge_data() |
Useful links
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