Shell script to do 'cdo' operation on multiple Netcdf file embedded in multiple folders

I have a directory on my Linux machine, let's name it MYDIR, with a number of folders labeled based on the years (1982, 1983, 1984, ..., 2022). Whithin each sub-folder, there are other folders named according to the months (01, 02, 03, ..., 12) and several NetCDF daily data inside each of these folders as well:

MYDIR [directory]
--1982[folder]   
----01[folder]
----02[folder]
----03[folder]
----12[folder]   
--1982[folder]
----01[folder]
----02[folder]
----12[folder]

I want to perform 2 operations on each file in all the folders. The operations are defined below.

cdo mergetime *.nc outfile.nc;
cdo ymonmean outfile.nc L4_GHRSST-SSTfnd_1982_01.nc

Finally, I want to save all L4_GHRSST-SSTfnd_1982_01.nc, L4_GHRSST-SSTfnd_1982_02.nc, ...,L4_GHRSST-SSTfnd_2022_01.nc, ..., L4_GHRSST-SSTfnd_2022_12.nc in a different folder named monmean in MYDIR. Can someone help me create a shell script which can perform the mentioned process?