Deep Convection-Aerosol Interactions using a Double Moment Convective Cloud Microphysical Scheme in the Kain-Fritsch Convection Parameterization

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Tuesday, 6 January 2015: 12:00 AM
223 (Phoenix Convention Center - West and North Buildings)
Kiran Alapaty, EPA, Research Triangle Park, NC; and S. Yu, X. Song, G. Zhang, C. G. Nolte, O. R. Bullock Jr., J. A. Herwehe, and J. S. Kain

In regional and global models, deep convection parameterization schemes use simple microphysics for conversion of cloud liquid water to rain drops. Because of the lack of a detailed representation of all cloud microphysical processes in these deep convection parameterizations, aerosol and deep cloud interactions cannot be studied. To facilitate the deep convection-aerosol interactions, a double moment convective cloud microphysical formulation has been implemented directly into the Kain-Fritsch convection parameterization available in the WRF model.

WRF model simulations using 12 km grid spacing were performed using a multi-scale version of the Kain-Fritsch scheme for the summer of 2006 over the continental US. In the first simulation, the default simple autoconversion scheme was used. A second set of simulations used a double moment convective microphysical scheme with varying aerosol concentrations. In the last simulation, climatological profiles of aerosol concentrations were used.

We find that model-predicted parameterized convective precipitation decreases with increased aerosol concentrations. Observed precipitation amounts and distributions are compared with each of these simulations and these results will be presented.