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Negative values

Added by Paula Santos 15 days ago

I am using CMIP6 future data for the u and v wind components. After applying the formula to calculate wind speed (w= √(u^2+ v^2 )) the values ​​are negative only in future data. I have already reviewed the code, applied the same calculation to historical data and this does not happen. Does anyone know what could be causing this? Thanks.


Replies (3)

RE: Negative values - Added by Karin Meier-Fleischer 12 days ago

You should give us more information. What is the CDO command you are using and can you upload the dataset or the output of 'ncdump -h infile' or 'cdo sinfon infile'?

RE: Negative values - Added by Paula Santos 12 days ago

I used the following commands:
cdo seldate: to select a specific date range;
cdo -L sellonlatbox: to select a specific geographic region
cdo merge: to combine multiple NetCDF files
cdo expr,'vel=sqrt(uas*uas+vas*vas)' : to calculate the wind speed from the zonal (uas) and meridional (vas) components.

When checking the number of negative values, the results are as follows:

Processing variable: vel_100m
Total number of values: 78938661
Number of negative values: 2879586

In addition, there is a segmentation fault. I have already reinstalled cdo, freed up memory, but the segmentation fault warning continues to appear.

RE: Negative values - Added by Karin Meier-Fleischer 12 days ago

It's hard to say what is going wrong without the data and the full CDO commands.

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