Kevin Thiel - February 26

Convective Meteorology (Mesoscale Dynamics)

Investigating GLM flash optical energy measurements with ABI and MRMS datasets

Kevin Thiel

Friday, February 26^th

3:00 pm

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https://meet.google.com/ksh-txvg-kni

Abstract: Recent deployment of the Geostationary Lightning Mapper (GLM) on the GOES-R series of satellites provides a new perspective of convection that can be utilized by the severe storms research and operational communities. As an optical sensor the GLM is able to capture the spatial footprint of lightning flashes, giving rise to gridded variables such as Flash Extent Density (FED) and Minimum Flash Area (MFA). These variables have already been proven useful indicating increasing thunderstorm severity, especially in cases of severe convection. Recent studies have confirmed the sensor’s designed detection efficiency and false alarm rates across the GLM field of view; however, detection efficiency is also shown to vary in convective modes as a function of cloud optical depth. Additionally, recorded GLM optical energy values have shown varied performance for optically thick convective clouds, such as thunderstorms producing large hail.

This study investigates the utility of a third gridded GLM variable, Total Optical Energy (TOE), as a thunderstorm severity and data quality tool by leveraging ABI and Multi-Radar/Multi-Sensor (MRMS) data in a bulk 7-week period of study: 13 April through 31 May 2019. Results show statistically significant differences of FED and MFA distributions between severe and non-severe convection, however TOE is not significantly different. GLM comparisons to MRMS vertically integrated and isothermal reflectivity observations suggest that TOE should be evaluated in conjunction with FED, MFA, and convective mode. Case studies are then examined to identify potential impacts of varying cloud optical depth on GLM flash characteristics.