Forcing¶

Data Override¶

When running MOM6 with the Flexible Modelling System (FMS) coupler, forcing can be specified by a data_table file. This is particularly useful when running MOM6 with a data atmosphere, as paths to the relevent atmospheric forcing products (eg. JRA55-do or ERA5) can be provided here. Each item in the data table must be separated by a new line, and contains the following information:

gridname: The component of the model this data applies to. eg. atm ocn lnd ice.
fieldname_code: The field name according to the model component. eg. salt
fieldname_file: The name of the field within the source file.
file_name: Path to the source file.
interpol_method: Interpolation method eg. bilinear
factor: A scalar by which to multiply the field ahead of passing it onto the model. This is a quick way to do unit conversions for example.

The data table is commonly formatted by specifying each of the fields in the order listed above, with a new line for each entry.

Example Format:: “ATM”, “t_bot”, “t2m”, “./INPUT/2t_ERA5.nc”, “bilinear”, 1.0

A yaml format is also possible if you prefer. This is outlined in the FMS data override github page, along with other details.

Speficying a constant value:

Rather than overriding with data from a file, one can also set a field to constant. To do this, pass empty strings to fieldname_file and file_name. The factor now corresponds to the override value. For example, the following sets the temperature at the bottom of the atmosphere to 290 Kelvin.

“ATM”, “t_bot”, “”, “”, “bilinear”, 290.0

Which units do I need?

For configurations using SIS2 and MOM, a list of available surface flux variables along with the expected units can be found in the flux_exchange file.