Question on SSTICE_YEAR_ALIGN and SSTICE_YEAR_START

[yugong]

Hi everyone, I’m a bit confused about the SST input in the F-compset. If I start a run from 2012-12-31 to 2013-01-10 and set the following:

./xmlchange SSTICE_YEAR_ALIGN=2012,SSTICE_YEAR_START=2012,SSTICE_YEAR_END=2013

Will the model use the SST data for December 2012 when running on 2012-12-31, and switch to the SST data for January 2013 when running from 2013-01-01 to 2013-01-10?


What version of the code are you using?
release-cesm2.1.5-0-g7a6c5b0

 

[dbailey]

What SSTICE file are you using? SSTICE_YEAR_START and SSTICE_YEAR_END refer to this dataset. So, if you start on January 1st, 2012 the default taxmode is cyclic, so it will use December from 2013. If you would prefer not to do that then:

SSTICE_YEAR_START=2000
SSTICE_YEAR_END=2013
SSTICE_YEAR_ALIGN=2000

START_DATE = 2012-01-01

This will use 2011 December.

 

[yugong]

What SSTICE file are you using? SSTICE_YEAR_START and SSTICE_YEAR_END refer to this dataset. So, if you start on January 1st, 2012 the default taxmode is cyclic, so it will use December from 2013. If you would prefer not to do that then:

SSTICE_YEAR_START=2000
SSTICE_YEAR_END=2013
SSTICE_YEAR_ALIGN=2000

START_DATE = 2012-01-01

This will use 2011 December.

Thank you for your reply! I am using the default SST data: sst_HadOIBl_bc_0.9x1.25_1850_2017_c180507.nc.

I believe i have figured out what's happening. When setting START_DATE=2012-01-01,SSTICE_YEAR_START=2000,SSTICE_YEAR_END=2013,SSTICE_YEAR_ALIGN=2000 , SST for 2011-12 will be used. However, if I set START_DATE=2012-01-17, SST for 2012-01 will be used. Is it correct?

However, i am still confused as to why model will use SST for 2011-12 instead of 2012-01 when START_DATE=2012-01-01 . Since we are running model in January(Jan 1st 2012), using SST for January seems more reasonable. Could you please help clarify this?

Any comment would be appreciated.

 

[yugong]

What SSTICE file are you using? SSTICE_YEAR_START and SSTICE_YEAR_END refer to this dataset. So, if you start on January 1st, 2012 the default taxmode is cyclic, so it will use December from 2013. If you would prefer not to do that then:

SSTICE_YEAR_START=2000
SSTICE_YEAR_END=2013
SSTICE_YEAR_ALIGN=2000

START_DATE = 2012-01-01

This will use 2011 December.

Do you mean SSTICE_YEAR_ALIGN=2011 ?

 

[dbailey]

I generally try to do SSTICE_YEAR_ALIGN = SSTICE_YEAR_START. This way the model year aligns with whatever the observation data has. So, our default SSTiCE forcing datasets run from 1850 to 2015 say. So, here I would say:

SSTICE_YEAR_START=1850
SSTICE_YEAR_END=2015
SSTICE_YEAR_ALIGN=1850

However, when the taxmode is 'cyclic', then if you run the model past 2015, it cycles back around to 1850.

Dave

 

[yugong]

I generally try to do SSTICE_YEAR_ALIGN = SSTICE_YEAR_START. This way the model year aligns with whatever the observation data has. So, our default SSTiCE forcing datasets run from 1850 to 2015 say. So, here I would say:

SSTICE_YEAR_START=1850
SSTICE_YEAR_END=2015
SSTICE_YEAR_ALIGN=1850

However, when the taxmode is 'cyclic', then if you run the model past 2015, it cycles back around to 1850.

Dave

Thanks! It makes sense to me now.