This is to illustrate how to set up a regionally coupled runs of HadCM3

• The idea is to suppress ocean atmosphere interaction is a specfied region while keep them fully coupled elsewhere. In the specified region, the air-sea interaction is suppressed by relaxing ocean surface temperature to specified values using very large relaxation coefficients. An example of such run is the experiment aehjg in the account hadbu.

• The following mod is needed to be include in HadCM3

The mod to supress ocean atmosphere interaction is a specfied region

• This is a fortran program which creates a text file where the relaxation coeffcients in the specified region are saved. This file will be read in the mod specified above.

Fortran program generates relaxation coefficinets for the specified region.

• The above fortran program reads in two files. One is a land-sea mask file and the other one is a text file which specified the first and last longitudes of the region latitude by latitude. Note that rexation region is generated by combining the mask file with this text file. You need to modify this text file for your own purpose. Included in the following is used to generate relaxation coeffcients over the Atlantic ocean.

mask file text file

• Then you need to prepare an ancillary file which has the reference temperature, SSS, Air temperature, and Ice depth. The reference temperature is the temperature the mod is relaxed to.

• Finally, in the umui, turn on "Haney forcing", update the reference temperature. See experiment aehjg.