P86 Comparison of the Morrison and Morrison-Gettelman microphysics within WRF and an update on the Separate Physics and Dynamics Experiment (SPADE)

Gustafson, William I., Jr., Po-Lun Ma, Heng Xiao, Balwinder Singh, Philip J. Rasch, and Jerome D. Fast, Pacific Northwest National Laboratory

The Morrison-Gettelman microphysics parameterization from the Community Atmosphere Model v5.1 was ported to the WRF model in the recent v3.5 release. This poster presents a comparison of the behavior of the existing Morrison scheme in WRF with the ported Morrison-Gettelman parameterization for grid spacings spanning the cloud “gray zone.” The cloud fields produced by the two parameterizations lead to differing cloud radiative forcing, which is particularly important for climate downscaling studies. And, the selection of the physics suite used in conjunction with the microphysics impacts how the two microphysics parameterizations change their behavior at differing grid spacings. The methodology used to show the grid spacing dependence is the Separate Physics and Dynamics Experiment (SPADE), which was introduced to the WRF community at last year’s WRF Users’ Workshop. An update on SPADE will be given using the microphysics as an example.