Ocean overflow regions

The CESM POP2 ocean model has added a new overflow parameterization for deep channel (e.g., Denmark Strait and Faroe Bank Channel) and continental shelf (Weddell and Ross Sea) overflows.  Clearly, the locations of these overflow regions are on relative to modern ocean and are inappropriate for Deep Time simulations where the continental and ocean basin configurations were different from the present day.  Therefore, in cases where the simulated ocean basin is significantly different from modern (including the LGM), we recommend that the overflow parameterization be turned off in the POP2 ocean model.

CESM notes on the POP2 parameterization of Physical processes:

See also:  Reference Manual Ocean Component of the Community Climate (


Turning off overflow regions for Deep Time simulations.


Default setting

Deep Time setting

overflows_on .true. .false.
overflows_interactive .true. .false.
lhoriz_varying_bckgrnd .true. .false.
ldiag_velocity .true. .false.
bckgrnd_vdc1 0.16 .524
bckgrnd_vdc2 0.0 .313


setenv INIT_TS_FILE b40.lgm21ka.1deg.002.pop.r.1499-01-01-00000newcoast_zeroUV_PSURF_Q110330
setenv OVF_FILE
setenv TAVG_FILE