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Anomalies over user-specified time steps

Added by Nathanael Harwood over 5 years ago

Hi all - I'm aware of the YDAYARITH etc operators that let you subtract a time series from the climatology

I'm trying to do the same with 5-day averages as the time step, with the following steps:

cdo -timselmean,5 -select,season=DJF 850tNHem.nc 850_5day.nc #create 5 day averages
cdo -timselmean,5 -select,season=DJF -ydaymean 850tNHem.nc 850_ymean.nc #create multi-year mean of the same steps (climatology)
cdo ydaysub 850_5day.nc 850_ymean.nc 850_anomaly.nc #sub time series from climatology - create anomaly.nc

Is this the correct approach? I'm getting Error (cdf_put_vara_double): NetCDF: Numeric conversion not representable

More than happy to provide subset of the data if needed


Replies (3)

RE: Anomalies over user-specified time steps - Added by Karin Meier-Fleischer over 5 years ago

Hi Nathanael,

please, upload test data to reproduce your problem.

-Karin

RE: Anomalies over user-specified time steps - Added by Nathanael Harwood over 5 years ago

Hi Karin,

No problems - Attached is a 2 year subset of the data, 850hPa temperature.

Many thanks

RE: Anomalies over user-specified time steps - Added by Karin Meier-Fleischer over 5 years ago

The warning tells you what is going wrong and what to do to solve the problem:

cdo ydaysub (Warning): Some data values (min=-190905 max=-176216) are outside the
    valid range (-32768 - 32767) of the used output precision!
    Use the CDO option -b 32 or -b 64 to increase the output precision.
cdf_put_vara_double : name=t  type=NC_SHORT  minval=-190905.000000  maxval=-176216.000000

Error (cdf_put_vara_double) : NetCDF: Numeric conversion not representable

Add -b 32 to your last cdo command
cdo -b 32 -ydaysub 850_5day.nc 850_ymean.nc 850_anomaly.nc                      #sub time series from climatology - create anomaly.nc

-Karin

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