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Ichthyop tutorial temperature tracking

In the temperature tracking part of the Ichthyop tutorial I noticed that there were sudden “jumps” in temperature from one frame to the next, every 3 days. The ROMS fields are provided at 3-day intervals. So it looks like temperature is interpolated spatially, but not temporally. Is that the explanation?

Hi Christophe

The problem is as follows: the ROMS "temp" is processed by the RequiredVariable.java generic class that allows (i) to detect the variable type, (ii) to integrate over time (iii) to interpolate in space.

In ROMS, the problem occurs in the first step (type detection, function "public Number get(double[] pGrid, double time)"). The first step looks whether the variable contains a record dimension (usually time, set as UNLIMITED in the NetCDF). If so, the model assumes that the variable should be interpolated.

In your file, the time is not set as a record dimension, hence it is not interpolated.

To correct this, go in a Termial and type the following command:

> ncks --mk_rec_dmn time file_in.nc file_out.nc

where "time" is the name of your time dimension.