IAU changes dry mass

to fix this, implement fixer from GMAO (https://onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0870.2007.00299.x).

https://github.com/NOAA-EMC/GFDL_atmos_cubed_sphere/pull/14
https://github.com/NOAA-EMC/fv3atm/pull/58

code from GEOS5 provided by @aerorahul