opposite of "subtrend"

Added by Bidyut Goswami about 4 years ago

Hi, I was wondering if there is any operator which works exactly opposite as "subtrend". What I mean is,

cdo trend ifile afile bfile
cdo subtrend afile bfile ifile_detrended

Is there any operator like "addtrend" such that,

cdo addtrend ifile_detrended afile bfile outfile

where, outfile would be basically same as my ifile

Thanks.

Replies (5)

RE: opposite of "subtrend" - Added by Ralf Mueller about 4 years ago

hi!

in this thread I explained what the outputs of the trend operator are about. you can create a data file based on the given formula (and your coefficients) using the expr operators and call the add operators on both inputs to get what you want.

hth
ralf

RE: opposite of "subtrend" - Added by Bidyut Goswami about 4 years ago

Hi Ralf,

Thanks for your suggestion. After reading the thread you had referred to, I tried the following:

### calculate trend
cdo -trend sst.nc afile.nc bfile.nc

### Detrend sst
cdo -subtrend sst.nc afile.nc bfile.nc sst_detrended.nc

### Retrieve the original SST
cdo -mul sst_detrended.nc bfile.nc sst_trended.nc
cdo -add sst_trended.nc afile.nc sst_retrived.nc

But there are differences between my original SST and the retrieved SST (please see the attached figures). Can you please suggest what am I missing here? I am attaching the original SST file for your reference.

Many thanks.
Bidyut

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