A Polarimetric and Microphysical Analysis of the Stratiform Rain Region of MCSs

Mesoscale convective systems (MCSs) are often poorly resolved in models, in particular the stratiform rain region trailing the main convective line. Poor parameterization of ice microphysical processes is partly to blame, due to limited understanding of such processes and a dearth of in situ measurements within the stratiform rain region of MCSs, particularly within regions such as the dendritic growth layer (DGL). Here we present analyses of the microphysical structure of the stratiform rain region of a number of MCSs, using data obtained by the University of North Dakota Citation aircraft during the Midlatitude Continental Convective Clouds Experiment (MC3E) and the NOAA P-3 aircraft during Plains Elevated Convection at Night (PECAN), as well as data from multiple S-band WSR-88D radars during these campaigns. Radar data were analyzed primarily using the new quasi-vertical profile (QVP) and column vertical profile (CVP) methodologies, with a focus on dual-polarization radar variables. These data were compared to in situ ice microphysical data including particle habits, particle size distributions, and ice water content to offer insight into how the microphysical characteristics of observed particles are reflected in the polarimetric radar data. Of particular interest was a dendritic growth layer marked with very pronounced polarimetric radar signatures. Novel algorithms for radar retrievals of microphysical characteristics of snow and ice based on the joint use of radar reflectivity Z and specific differential phase K_DP were tested using these datasets.