89th American Meteorological Society Annual Meeting

Tuesday, 13 January 2009
Total Lightning Activity within Extreme Weather Events Observed by the TRMM LIS and OTD
Hall 5 (Phoenix Convention Center)
Lawrence D. Carey, University of Alabama in Huntsville, Huntsville, AL; and W. A. Petersen and H. J. Christian Jr.
The overall objective of this project is to investigate the precipitation and lightning characteristics and underlying environmental controls of extreme weather events over the contiguous United States (CONUS) using TRMM (Tropical Rainfall Measuring Mission) LIS (Lightning Image Sensor) and OTD (Optical Transient Detector) observations. A large sample of TRMM (10+ years) and OTD (5 years) total lightning and precipitation property data base is available to study the instantaneous characteristics of extreme weather events. The LIS and OTD data are combined with National Lightning Detection Network (NLDN) observations to examine the total and cloud-to-ground (CG) lightning flash rate and density, the intracloud:CG ratio, and positive CG percentage. These instantaneous satellite characteristics can be used for basic science studies to better understand the physical and dynamical connections between lightning and precipitation and their meteorological controls. They can also provide a “first-look” of extreme weather events leading up to future observations (e.g., NASA GPM, GOES-R GLM) for use in climate studies and the short-term prediction and warning process. Initially, extreme weather events are defined by the NOAA Storm Data storm reports of tornadoes, large hail (at least 0.75 inch) and strong straight-line winds (at least 50 kts). However, the definition can be expanded later to include flooding, extreme winter weather, lightning-induced forest fires etc. Over CONUS, there are over 70,000 severe storm reports in the TRMM spatial domain (< 35° N) from 1998-2007 and over 100,000 storm reports in the OTD spatial domain (5/1995-4/2000). Temporal co-location is on the order of 1% (i.e., 1000's of coincident overpasses), providing a statistically significant sample of instantaneous lightning properties. This instantaneous behavior of lightning in extreme weather is then compared to that of normal thunderstorm events, or randomly sampled instantaneous LIS/OTD events in which the extreme events have been eliminated from the population. Preliminary results describing the instantaneous behavior of total lightning within a large sample of extreme weather events will be presented at the conference and should provide a complementary view to the existing limited database of full life-cycle case studies from ground-based observational systems.

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