Evaluation of Convective Updraft Spacing in NU-WRF Simulations using Forward-simulation and Feature Analysis of KDP Columns

The well known wide range of convective updraft properties obtained from different microphysics schemes in cloud-resolving and limited-area models points to a lack of sufficient quantitative understanding of coupled dynamical and microphysical processes in deep convection updrafts, owing at least in part to a paucity of in situ measurements to improve models. General insight into model performance in simulating deep convection systems has been gained from analysis of quantitative precipitation estimates, radar reflectivity CFADs, and convective-stratiform partitioning. The increasing availability of polarimetric radar data now permits development of similarly efficient methods to evaluate the spatial distribution and microphysics of deep convective updrafts in simulations. Here we compare observations of KDP columns observed above the environmental melting level with those simulated with the NASA Unified Weather Research and Forecasting (NU-WRF) model during an MCS over the Southern Great Plains on 20 May 2011 during the Midlatitude Contintental Convective Clouds Experiment. Forward simulations are performed with both bin and bulk microphysics schemes in NU-WRF. Focus is placed first on simple measures of updraft horizontal spacing and linearity of convective organization, which are relatively stable across several microphysics schemes examined, and second on the degree of vertical KDP extent.