Drop-Size Distribution Measurements in Mesoscale Convective Systems during PECAN

Improving scientific understanding of microphysical processes in nocturnal mesoscale convective systems (MCSs) is an important goal of the Plains Elevated Convection At Night (PECAN) experiment.  During PECAN, over 2000 minutes of DSD data were collected using three Parsivel disdrometers, providing a data set that spans different MCS lifecycle stages and archetypes from 10 different cases.  Although many studies have examined bulk rain variables in MCSs (e.g., radar reflectivity factor or rainfall rate), few studies have documented surface DSD variability in different regions of the MCS or DSD variability among different MCS cases and archetypes.  Thus, the goal of this study is to examine DSD characteristics using MCS cases collected during the PECAN experiment. 

For each MCS case, radar and disdrometer data are used to classify DSD data into convective and stratiform categories, and further subclassifications are performed for convective (leading edge, convective core, trailing edge) and stratiform (e.g., transition zone, or trailing, parallel and leading stratiform) regions.  Individual case studies are presented to highlight DSD variability within convective and stratiform regions, and dual-polarization radar signatures associated with interesting DSD variability are examined.  Finally, DSD data are composited to obtain a more generalized view of MCS DSDs and understand DSD variability among MCS cases and different subclassifications.