Resolution dependance of Convection, Macro- and Micro-Physical Moist Processes in the GEOS-5 AGCM: Spanning from 200 to 12 km

Abstract:

The MERRA-2 version of the GEOS-5 Atmospheric General Circulation Model (AGCM) is
currently in use in the NASA Goddard Modeling and Assimilation Office (GMAO) for
simulations at resolutions ranging from 200 to 12 km in atmosphere only,
coupled ocean-atmosphere, and data assimilation modes. Although the implementation
of a set of ad-hoc "resolution-aware" parameters resulted in improvements at high
resolution and a more seamless model behavior, increases of simulated cloud cover
with increased resolution persisted. To address this spurious change in cloud cover,
an objective set of criterion for "convective" and "stratiform" systems that is unrelated
to the split between "parameterized" and "resolved" was implemented, along with an explicit
dependance on the resolved vertical motion field.