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To help users to improve S2S CMA MARS requests performance. via the WebAPI

A good understanding of the MARS efficiency issues is essential especially for users that are interested in downloading large amounts of data.

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

• centre (CMA, ECMWF, NCEP, JMA, ...)
  • realtime or reforecast
    •  type of data (control forecast or perturbed forecast)
      • type of level (single level or pressure level or potential  temperature)
        • Hdates HindcastDates (20152014-01-01 or 20152014-01-0502 or 20152014-01-0803, ...)
          •  time-steps
            • members (for perturbed forecast)
              • levels (for pl or pt)
                • parameters

The idea is to have in request as much data as possible from the same tape file, all time-steps, all members, all parameters for a type of level, a type, a HdateHindcastDate

Following the previous paragraph,  the natural way to group requests would be:
all parameters, all levels, all members, all time-steps for 1 HdateHindcastDate.

Note the following:

1. 'all' means 'all' that the user wants. It doesn't have to be all parameters.
2. If a user is interested only on z500,  he may request more Hdates HindcastDates in one go, since the overall request will not be so big.

for HdateHindcastDate in HdateHindcastDate-list
     s2S-request(Hdate)

     S2S-request

(HindcastDate)

for HyearHindcastYear in HyearsHindcastYears 
    for HmonthHindcastMonth in HyearHindcastYear
        for HdaysHindcastDay in HmonthHindcastMonth
             HdateHindcastDate = HyearHindcastYear-HmonthHindcastMonth-HdayHindcastDays

                 s2S-request(HdateHindcastDate)

for each HyearHindcastYear from 2010 to 2014

    for HmonthHindcastMonth in April04, June06

        for HdayHindcastDay in HmonthHindcastMonth

             HdateHindcastDate = HyearHindcastYear-HmonthHindcastMonth-HdayHindcastDay

             s2S-request(HdateHindcastDate)