All comprehensive Earth System models (ESMs) include Land component that simulates terrestrial biophysical and biogeochemical processes. Typically, all sub-units within a land grid receive the same downward fluxes of radiation and precipitation from an atmospheric grid. ESMs assume that the canopy air is clean and ignore tracers that may be present in the canopy air (e.g. dust or fire emissions). Parameterizations have been developed to capture the effects of mountains, vegetation structures, and snow impurities on the surface radiation budget, however, these parameterizations have not been implemented in any CMIP6-class ESMs. This project will undertake the following model developments:
- Radiation flux parameterization accounting for the effects of mountain shading and multiple reflections between mountains and snow;
- Parameterizations for black carbon and dust mixing in snow and associated light absorption and scattering processes;
- Multi-layer canopy energy transfer accounting for the tracers (e.g dust and black carbon) in the canopy air space; and
- Interactions of the above improvements with sub-grid land-heterogeneity (e.g., different vegetation/plant functional types, elevation bands, mountain aspects, hydrological hill-slopes, etc.).