123 Preliminary Analyses of Disdrometer Observations in the 2016 VORTEX-SE Field Campaign

Wednesday, 9 November 2016
Broadway Rooms (Hilton Portland )
Jessica Bozell, Purdue Univ., West Lafayette, IN; and D. T. Dawson II, R. Tanamachi, and S. J. Frasier

Knowledge of raindrop size distributions (DSDs) is critical to understanding the microphysics of convective storms.  It is well known that DSDs can vary widely both within and between storms in different environments, and recent results from numerical simulations and limited observational studies have shown that supercells in particular exhibit systematic variations in DSDs that may strongly impact outflow and cold pool thermodynamics and tornado potential.  Unfortunately, there is a great lack of in situ measurements available, particularly in southeastern-U.S. tornado environments, which are often characterized by lower magnitudes of CAPE than their better-studied counterparts in the U.S. Great Plains.  Given the large societal impact of tornadoes in the southeastern U.S., high quality targeted in situ observations of DSDs in tornadic and potentially tornadic convective storms will help improve polarimetric radar retrievals of DSD parameters, as well as constrain microphysics parameterizations within numerical models.

During the 2016 VORTEX-SE field program, Purdue University--in cooperation with the University of Oklahoma and the National Severe Storms Laboratory--deployed four instrumented packages, dubbed Portable In Situ Precipitation Stations (PIPS), within potentially tornadic convective storms.  The PIPS are each outfitted with an OTT Parsivel2 laser disdrometer, and collect DSDs at intervals of 10 s.  The purpose of this study is to present the preliminary results and analyses from the PIPS data collected during several intensive operating periods (IOPs) in the VORTEX-SE field program. Polarimetric variables are derived from the disdrometer data and are compared to observations from nearby radars such as the Nexrad and UMass X-Pol radars. High frequency (1-s) conventional meteorological observations (temperature, relative humidity, pressure, wind speed and direction) were also collected and are compared to the data collected from the Texas Tech University (TTU) StickNet observations. For further comparison, differences between the DSDs collected during the VORTEX-SE project and the earlier VORTEX2 project (2009-2010) are investigated.

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