Kevin Thiel - January 28

Convective Meteorology (Mesoscale Dynamics)

Intercomparisons of Geostationary Lightning Mapper with ABI and MRMS Datasets

Kevin Thiel

Friday, January 28

3:00 PM

Virtual

Lightning observations from the GOES-R Geostationary Lightning Mapper (GLM) provides a new view of convection for the forecasting and severe storms research communities. As an optical sensor, the GLM is able to provide the location and areal extent of detected flashes, giving rise to gridded products such as Flash Extent Density (FED), Minimum Flash Area (MFA), and Total Optical Energy (TOE). Numerous data validation efforts have attempted to understand the operational applications and limitations of GLM data, and have found that GLM flash detection efficiency can vary spatially and temporally across the field of view. Variations also exist with respect to severe and local storms, with factors such as optical depth, flash initiation heights, and viewing angles from the perspective of GOES-16 and GOES-17.

This study provides a two-pronged approach to validating gridded GLM data through the perspective of the MRMS’s Maximum Expected Size of Hail (MESH), Isothermal Reflectivity at -10 °C, and Vertically Integrated Ice (VII), along with the ABI’s Clean-IR Brightness Temperature at cloud top. The first approach is through a case study of a long-track, tornadic supercell in Alabama on 25 March 2021. The second is a bulk study approach from seven continuous weeks in April and May of 2019 across the central and eastern United States. Results show that the geometric perspective lightning flashes can create considerable variations in GLM FED and TOE values within severe and local storms, however FED and MFA correspond well with changes in -10 °C Isothermal Reflectivity, especially for values greater than 40 dBZ. TOE provides the greatest degree of variability, with viewing angle, optical depth, and local flash characteristics all appearing to impact the GLM’s optical energy measurements.