[MITgcm-support] Rbcs package question

[Katarina Merk]

Hi, 

I am trying to implement the rbcs package with changing relaxation temperatures but I am encountering unexpected model behavior.

I have tried with both cyclic data in a single file and non-cyclic data in multiple files and compared it to having a single file with only one record in a very simplistic example with the same initial temperature at all grid points, a higher relaxation temperature at all grid points, and Mrbc = 1 at all grid points. Would it be possible to get some guidance in how my implementation is incorrect and resulting in temperature decreasing in some cases? 

Single file, one record: 
With a single file with only one record the temperature increases with time as expected. 

 useRBCtemp=.TRUE.,
 tauRelaxT=86400.,
 relaxMaskFile='T_relax_mask.KM.bin',
 relaxTFile='temperature.KM.bin',
# rbcsSingleTimeFiles=.FALSE.,
# rbcsForcingPeriod=86400.,
# deltaTrbcs=86400.,
# rbcsForcingCycle=31536000.,
# rbcsForcingOffset=43200.,

Multiple files, non-cyclic: 
When I have non-cylic data in multiple files (each file has the same relaxation temperature which is higher than the initial temperature), the temperature decreases with time. 

 useRBCtemp=.TRUE.,
 tauRelaxT=86400.,
 relaxMaskFile='T_relax_mask.KM.bin',
# relaxTFile='temperature.KM.bin',
 rbcsSingleTimeFiles=.TRUE.,
 rbcsForcingPeriod=86400.,
 deltaTrbcs=86400.,
# rbcsForcingCycle=31536000.,
# rbcsForcingOffset=43200.,


Single file, multiple records (cyclic):
When I have cyclic data in one file it increases with time as expected. However, if I change the first record to be the initial temperature at all gird points, followed with a higher relaxation temperature at each following record at all grid points, the simulation begins with the temperature decreasing. 

 useRBCtemp=.TRUE.,
 tauRelaxT=86400.,
 relaxMaskFile='T_relax_mask.KM.bin',
 relaxTFile='temperature_2.KM.bin',
 rbcsSingleTimeFiles=.FALSE.,
 rbcsForcingPeriod=86400.,
# deltaTrbcs=86400.,
 rbcsForcingCycle=31536000.,
 rbcsForcingOffset=43200.,

Thank you,
Katarina
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