B1850 startup: ocean spun up or not?

[wagmanbe@utexas_edu]

Hi, I can't tell for sure whether the B1850C5 compset starts from a spun-up ocean initial condition in a "startup" run, or from Levitus. Here's the name of the inputfile from the ocean log. Can anyone tell if it's indeed Levitus? &INIT_TS_NML INIT_TS_OPTION  = ccsm_startup                                                                                                                                                                                                                       INIT_TS_FILE    = /scratch/projects/xsede/CESM/inputdata/ocn/pop/gx1v6/ic/ts_PHC2_jan_ic_gx1v6_20090205.ieeer8                                                                                                                                             I suspect it's Levitus, but want to confirm. In a similar inquiry (below), Levitus was the answer, but some B compsets start from spun up conditions. http://forum.cgd.ucar.edu/cesm120-b-compset-ccsmstartup-ics-source Thanks! 

 

[hannay]

The variable RUN_TYPE should indicate if you are starting from Levitus   or from a spunup state,     The  INIT_TS_FILE also shows that you are starting from Levitus. INIT_TS_FILE    = /scratch/projects/xsede/CESM/inputdata/ocn/pop/gx1v6/ic/ts_PHC2_jan_ic_gx1v6_20090205.ieeer8                    

 

[hannay]

The variable RUN_TYPE should indicate if you are starting from Levitus   or from a spunup state,     The  INIT_TS_FILE also shows that you are starting from Levitus. INIT_TS_FILE    = /scratch/projects/xsede/CESM/inputdata/ocn/pop/gx1v6/ic/ts_PHC2_jan_ic_gx1v6_20090205.ieeer8                    

 

[njn01]

There is additional information in the ocn.log.* file that will tell you if you are using Levitus or spun-up initial conditions, so you will need to look there.  Just below the place where the contents of the INIT_TS_NML namelist are echoed to the ocn.log file, you will see where the model actually tells you what file(s) it has just read.  For example,  in a typical ccsm_startup case, you would see the lines:Initial 3-d T,S read from file:/glade/p/cesmdata/cseg/inputdata/ocn/pop/gx1v6/ic/ts_PHC2_jan_ic_gx1v6_20090205.ieeer8andfile read: /glade/p/cesmdata/cseg/inputdata/ocn/pop/gx1v6/ic/ts_PHC2_jan_ic_gx1v6_20090205.ieeer8The output is telling you, in this example, that the model is reading the "PHC2" dataset, which is Levitus data blended with Arctic data (see https://www.arcus.org/arctic-info/archive/17709 for example).If, in the rare exception that your case uses the  INIT_TS_OPTION = ccsm_startup with the INIT_TS_SUBOPTION = 'spunup' suboption, then you would find that the model tells you it is reading an existing POP restart file.  The use of the "spunup" suboption is not common, and it should only be used in limited situations by users with deep understanding of  the consequences of their choice.  

 

[njn01]

There is additional information in the ocn.log.* file that will tell you if you are using Levitus or spun-up initial conditions, so you will need to look there.  Just below the place where the contents of the INIT_TS_NML namelist are echoed to the ocn.log file, you will see where the model actually tells you what file(s) it has just read.  For example,  in a typical ccsm_startup case, you would see the lines:Initial 3-d T,S read from file:/glade/p/cesmdata/cseg/inputdata/ocn/pop/gx1v6/ic/ts_PHC2_jan_ic_gx1v6_20090205.ieeer8andfile read: /glade/p/cesmdata/cseg/inputdata/ocn/pop/gx1v6/ic/ts_PHC2_jan_ic_gx1v6_20090205.ieeer8The output is telling you, in this example, that the model is reading the "PHC2" dataset, which is Levitus data blended with Arctic data (see https://www.arcus.org/arctic-info/archive/17709 for example).If, in the rare exception that your case uses the  INIT_TS_OPTION = ccsm_startup with the INIT_TS_SUBOPTION = 'spunup' suboption, then you would find that the model tells you it is reading an existing POP restart file.  The use of the "spunup" suboption is not common, and it should only be used in limited situations by users with deep understanding of  the consequences of their choice.