output issues for restart

[weiyeyao@umich_edu]

I'm running cam4.0 model with output data of 30 day mean to a certain point,
and I want to restart and output data as 6 hourly instantaneous data in continue to that.
I changed the option NHTFRQ to -6 in namelist file after finished the first period run.

After I restarted it, I found the out put data is still 30 day mean. I hoped it could started to write in a new file but it's still in the old data file.

How can I restart and output the 6 hourly data in a new data file from the restart point i just created?

 

[eaton]

In order to change the characteristics of the history output you need to do a branch run. A restart run will not work because the characteristics of the history output are read from the restart file when a restart run is done, and so will be unchanged by a restart, as you noticed.

Doing a branch run isn't documented very well, so here are some pointers. (The information below is specific to CAM4. In CAM5 the docn component replaces the camdom component with a corresponding change in the namelist variable used to specify the branch file) . Assume the run script has the following shell variables set:

brdir  - the directory that contains the restart files being used for the
          branch run (this could be the run directory).
brdate - branch date -- this is a string in the format yyyy-mm-dd-sssss 
            where yyyy is the year, mm is the month, dd is the day of
            month, and sssss are seconds past 0Z
case - case name

The build-namelist command needs the following information to specify the restart files used by the various components for a branch run:

build-namelist 
-cice_nl "&ice ice_ic='$brdir/$case.cice.r.$brdate.nc' /" 
-namelist "&atm start_type='branch' 
         restart_file='$brdir/$case.cpl.r.$brdate.nc' 
         cam_branch_file='$brdir/$case.cam2.r.$brdate.nc' 
         dom_branch_file='$brdir/$case.camdom.r.$brdate' 
         nrevsn='$brdir/$case.clm2.r.$brdate.nc' /"