Version 2 (modified by jwhile, 6 years ago) (diff)

Last edited Timestamp?


Author : James While

ticket : #1328

Branch : /2014/dev_r4650_UKMO14.5_SST_BIAS_CORRECTION


Description

This code change will allow NEMO to read in fields of SST biases and remove theses biases from the observations before the observations are compared to the model.

This is a fairly minor change that has no impact on model dynamics. My plan for testing is to run the standard NEMO SETTE tests, but also conduct a run where the model is given a bias field and show that the observations change appropriately between the input observation files and the output feedback file.


Testing

Testing could consider (where appropriate) other configurations in addition to NVTK].

NVTK Tested'''YES
Other model configurations'''YES
Processor configurations tested[ Tested in SETTE tests ]
If adding new functionality please confirm that the
New code doesn't change results when it is switched off
and ''works'' when switched on
'''YES (results from SETTE tests agree exactly with tests using unaltered code)

(Answering UNSURE is likely to generate further questions from reviewers.)

'Please add further summary details here'

The code has been ran for many years in the Met Office operational configurations (at Vn3.2 and Vn3.4).

Bit Comparability

Does this change preserve answers in your tested standard configurations (to the last bit) ?'''YES
Does this change bit compare across various processor configurations. (1xM, Nx1 and MxN are recommended)'''YES
Is this change expected to preserve answers in all possible model configurations?'''YES
Is this change expected to preserve all diagnostics?
,,''Preserving answers in model runs does not necessarily imply preserved diagnostics. ''
'''NO'''

If you answered '''NO''' to any of the above, please provide further details:

If ln_sstbias=.TRUE. (Default is FALSE) then the SST observations in the output feedback files from the observation operator code will have had a bias field removed from them.

The changes come about because of updates to OBS/diaobs.F90 and OBS/obs_sstbias.F90

This change is namelist controlled and has to be specifically requested by the user.

No other diagnostics are affected


System Changes

Does your change alter namelists?'''YES '''
Does your change require a change in compiler options?'''NO '''

If any of these apply, please document the changes required here…….

Two new options are now in namobs in the shared reference namelist: "ln_sstbias" (default is FALSE) which switches on/off the bias correction and "sstbias_files", which specifies the file to read the bias field from. Also, I have changed "sstfbfiles = sstfbfiles = 'sst_01.nc' 'sst_02.nc' 'sst_03.nc' 'sst_04.nc' 'sst_05.nc' " to "sstfbfiles = 'sst_01.nc'"; this is purely to make the shared namelist cleaner.


Resources

'' For every bias field read in an extra 2-D array is required to store the data, causing a modest increase in the amount of memory required


IPR issues

Has the code been wholly (100%) produced by NEMO developers staff working exclusively on NEMO?'''NO

If No:

If No:

The code has been developed as part of the NEMOVAR consortium.