Utilizing Geostationary Lightning Mapper (GLM) Data for Verification of Convective Allowing Models (CAMs)

The development of convective allowing models (CAMs), such as the High Resolution Rapid Refresh (HRRR) and Rapid Refresh Forecast System (RRFS), requires verification of convective systems to understand and improve model performance. While radar reflectivity data is commonly used for this verification, there are significant gaps in radar coverage, especially over water. Satellite-based lightning observations can provide an alternative to radar observations for verifying the presence and intensity of convective storms without spatial coverage limitations.

NOAA’s Global Systems Laboratory (GSL) Assimilation and Verification Innovation Division (AVID) has been utilizing Geostationary Lightning Mapper (GLM) observations for verification in support of the lab’s ongoing development of CAMs. GLM is an instrument onboard the Geostationary Operational Environmental Satellites - R Series (GOES-R) that detects lightning by monitoring changes in brightness of image pixels. Several GLM products are available to describe the observed lightning, including flash extent density (FED), which is a measure of the number of flashes that overlap with a GLM pixel in one minute. Although thunderstorm electrification processes are not simulated in the CAMs developed by GSL, the FED can be approximated from the model’s column-integrated graupel mass and then verified against observed FED values from the GLM.

This presentation will describe the methods used to perform lightning verification of the HRRR against the GLM, including data processing, parameterization, and interpolation, and how the results of this verification compare to traditional radar reflectivity verification.