Overview of Purdue's Mobile Disdrometer Operations During VORTEX-SE 2016-2017

A primary objective of VORTEX-SE is to study the microphysical and thermodynamical properties of the downdrafts of potentially tornadic storms in the southeastern-U.S. Many tornadic storms in this region develop in environments characterized by relatively lower instability, weaker low-level lapse rates, and deeper moist layers than their counterparts in the U.S. Great Plains. These differences in environments may have important impacts on microphysical characteristics such as the rain drop size distribution (DSD), and on downdraft and cold pool thermodynamic properties. Yet, the level of variability of DSDs both within and between these regions and environments, as well as their impact on tornado potential, is still largely unknown and moreover has been less studied in the lower-CAPE tornado environments common to the southeast U.S. Thus, there is a great need to characterize DSDs in tornadic or potentially tornadic storms in this region with high quality, targeted, and coordinated in situ and remote measurements.

To this end, Purdue University, the University of Oklahoma, and the National Severe Storms Laboratory have jointly designed and built four mobile instrumented probes, dubbed Portable In Situ Precipitation Stations (PIPS), in support of the aforementioned VORTEX-SE objectives. The PIPS were successfully deployed in several intensive operating periods (IOPs) during the VORTEX-SE 2016 and 2017 field programs. During the 2017 field program, two mobile radar platforms: the University of Massachusetts X-band polarimetric radar, and the Shared Mobile Atmospheric Research & Teaching Radar (SMART-R) C-band polarimetric radar, performed special targeted sectors over the PIPS during several IOPs. In this study we present an overview of these operations, with an emphasis on the 2017 field program. We will discuss preliminary analyses of the PIPS data and comparisons with the aforementioned radar observations.