Setup

Copy the demo scripts to your working directory

# logon FRAM or Betzy
ssh -Y -l <username> fram.sigma2.no
# or
ssh -Y -l <username> betzy.sigma2.no


# clone the sample scripts to your working directory
cd /cluster/work/users/$USER
git clone https://github.com/YanchunHe/noresmpp
cd noresmpp

Interpolate CAM hybrid-sigma coordinate to pressure levels

Inspect the script, and you should be able to run task1.sh to interpolate air temperature (T) to pressure levels.

cd task1
./task1.sh

Exercise

• Try interpolate specific humidity in the atmospheric output
• Only interpolate to 200,500,850,1000 hPa levels, and view lat/lon distribution on pressure levels

Remap BLOM tripolar grid 1x1 degree grid

You should be able to run task2.sh to interpolate sst to 1x1d grid in the NorESM2-LM historical run for year 2010-2014, and compare to HadISST.

cd task2
./task2.sh

Exercise

• Try another experiment NSSP370frc2_f19_tn14_20191014 for future SSP370 scenario. You only need to change the varilable casename in the script.
• Try only interpolate months 6, 7, 8 of years 2010-2014.

Rotate vector variable of BLOM from the model’s i,j directions to zonal,meridional directions

• You should be able to run task3.sh to rotate barotropic flow to zonal and meridional directions.
• Run ncl task3.ncl to rotate and plot the velocity fieds, and find the difference before and after rotation.

cd task3
# rotate with NCO and view with ncview
./task3.sh

# or
# rotate and view with NCL
ncl task3.ncl

Exercise

• Use your own program (python, NCL, matlab, fortran, etc) to rotate the vectors.

Solution

For example, use NCL

gid     = addfile("grid.nc","r") 
angle   = gid->angle
fid     = addfile("blom_output.nc","r")
U       = fid->mxlu
V       = fid->mxlv
Urot    = U*cos(angle)-V*sin(angle)
Vrot    = U*sin(angle)+V*cos(angle)