Generate JRA55-do relative humidity forcing file

This repository contains code to create a JRA55-do relative humidity input file from the provided specific humidity fields. This is intended to be used when one wants to provide relative humidity as a forcing field instead of specific humidity (e.g. to keep the relative humidity constant when applying an air temperature perturbation). See discussion here: COSIMA/cice5#57

The make_rhuss.py file creates the relative humidity file from the JRA55-do specific humidity file. Currently this is setup to convert only the RYF 1990-1991 file, but is easy to generalise.

The "main" branch will work with JRA55 v1.4 data. The "jra55_v1-3" branch will work with JRA55 v1.3 data.

Usage:

On an interactive job on Gadi:

qsub -I -X -P e14 -q express -l mem=32GB -l storage=gdata/hh5+gdata/ik11+gdata/e14+gdata/ua8 -l wd

run the following:

module use /g/data3/hh5/public/modules
module load conda/analysis3-21.04

python3 make_rhuss.py

To use this properly the required configuration changes are:

• Use a CICE5 executable which includes the updated code (COSIMA/cice5#59).

• change qair_i to relh_i in ice/input_ice.nml

• change qair_ai qair_i to relh_ai relh_i in namcouple

• in atmosphere/forcing.json change:

      "filename": "INPUT/RYF.huss.1990_1991.nc",
      "fieldname": "huss",
      "cname": "qair_ai"

to

      "filename": "INPUT/RYF.rhuss.1990_1991.nc",
      "fieldname": "rhuss",
      "cname": "relh_ai"