wiki:udg/ecoms/dataserver/interfaces/matlab

Version 3 (modified by rodri, 9 years ago) (diff)

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Function:

As for Phyton, a Matlab function (loadSystem4.m) has been created in order to access the hindcast of the System4 stored in the SPECS-EUPORIAS Data Portal in a user-friendly way. This would be a typical call to the function:

 [data,run,ens,frc,lat,lon] = loadSystem4(dataset,var,season,leadMonth,'members',members,'xlim',xlim,'ylim',ylim,'user',user,'password',password);

The input arguments are next described:

  • dataset: A string indicating the full URL path to the OPeNDAP dataset (see Available Datasets to check the catalog of available datasets).
  • var: Variable code. Values currently accepted are tas, tasmin, tasmax, pr or mslp. However, note that new variables and datasets will be progressively included.
  • season: A cell of two strings indicating the first and final months of analysis. A single month ({'Jan';'Jan'}) or a standard season ({'Dec';'Feb'}) can be specified. Note that months are indicated by their three first letters.
  • leadMonth: Lead time (in months) to consider. For instance, leadMonth = 1 for January forecasts means considering the initialization of the first of December .
  • members: Vector of length n indicating the n members to consider.
  • xlim: Vector of length = 2 with minimum and maximum longitude coordinates (in decimal degrees) of the bounding box selected.
  • ylim: Vector of length = 2 with minimum and maximum latitude coordinates (in decimal degrees) of the bounding box selected.
  • user: Username for accessing the OPeNPAD dataset.
  • password: Password for accessing the OPeNPAD dataset.

These are the arguments returned by the function:

  • data: Cell with n elements (one for each year), in which each element (a 2-D matrix) is the data for a particular year. A 2-D matrix of i rows and j columns, i represents the forecast times and j the grid-points selected.
  • run: Cell with n elements (one for each year) corresponding to the initialization times selected. Note that there is an initialization time associated to each forecast time.
  • ens: List of length n, where n is the number of members of the ensemble selected by the members argument.
  • frc: Cell with n elements (one for each year) corresponding to the forecasts times.
  • lat: Vector with the latitudes of the selected domain.
  • lon: Vector with the longitudes of the selected domain.

Example:

In this example, the loadSystem4 function is used to read the maximum temperature for the Iberian Peninsula in August for the whole hindcast period (1981-2010), considering the initialization of the first of June (two-month lead time thus) for a single member (member5, for instance).

dataset = 'http://www.meteo.unican.es/tds5/dodsC/system4/System4_Seasonal_15Members.ncml';
var = 'Maximum_temperature_at_2_metres_since_last_24_hours_surface';
 [data,run,ens,frc,lat,lon] = loadSystem4(dataset,var,{'Aug';'Aug'},2,'members',5,'xlim',[-10 5],'ylim',[35 45]);

The data can be plotted by using the functions from MeteoLab, the open-source Matlab toolbox for statistical analysis and data mining in Meteorology created by the Santander Meteorology Group.

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