3: Modify wind stress#
Wind stress plays a critical role in driving ocean currents and is a key factor in shaping the overall patterns of large-scale ocean circulation and, consequentialy, the climate. Further details on how wind stress affects the ocean circulation are discussed in this manuscript.
Create a case called g_windstress by cloning the control experiment case.
Verify that the run length is set to 1 year.
Modify the subroutine rotate_wind_stress in forcing_coupled.F90 to increase the first (x) component of the wind stress by 25%.
Build and run the model for one year.
Compare the simulations using ncview/ncdiff, etc.
Click here for hints
How do I compile and run?
You can compile with the command:
qcmd -- ./case.build
You can run with the command:
./case.submit
How do I check the lenght of the run?
Use xmlquery to search for the variables that control the run length
Click here for the solution
Clone a new case g_windstress from your control experiment with the command:
cd /glade/u/home/$USER/code/my_cesm_code/cime/scripts/
./create_clone --case /glade/u/home/$USER/cases/g_windstress --clone /glade/u/home/$USER/cases/g_control
Case setup:
cd /glade/u/home/$USER/cases/g_windstress
./case.setup
Verify that the run length is 1 year:
./xmlquery STOP_N
./xmlquery STOP_OPTION
Copy the forcing_coupled.F90 file from the control case to the ocean SourceMods.
cp /glade/u/home/$USER/code/my_cesm_code/components/pop/source/forcing_coupled.F90 /glade/u/home/$USER/cases/g_windstress/SourceMods/src.pop
Edit the file forcing_coupled.F90 in the rotate_wind_stress routine after SMFT(:,:,1,:) is defined:
SMFT(:,:,1,:) = SMFT(:,:,1,:) * 1.25
If needed, change job queue and account number. For instance:
./xmlchange JOB_QUEUE=tutorial,PROJECT=UESM0013 --force
Build and submit:
qcmd -- ./case.build
./case.submit
When the run is completed, look into the archive directory for: g_windstress.
(1) Check that your archive directory on derecho (The path will be different on other machines):
cd /glade/derecho/scratch/$user/archive/g_windstress/ocn/hist
ls
Test your understanding#
What are the impacts of increased zonal wind stress?
Where do you thinkt he impacts would be largest in the ocean?
How do you think the changes would compare if you increased meridional wind stress?