Variables required to run the CM3 evaluation with ACCESS-ENSO-Recipes

The following variables are required:

- `pr`
- `ts`
- `tauu`
- `tos`
- `zos`
- `nhf`, defined as:  
  `nhf = -hfds - hfss + rlds - rlus + rsds - rsus`

*Note: `ts` and `tos` can be used interchangeably.*