GLD360 Performance Relative to TRMM LIS Journal of Atmospheric and Oceanic Technology

This study evaluates the performance of the operational and reprocessed Global Lightning Dataset 360 (GLD360) data relative to the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) during 2012–14. The analysis compares ground- and space-based lightning observations to better characterize the pre- and postupgrade GLD360. The reprocessed, postupgrade data increase the fraction of LIS flashes detected by the GLD360 [i.e., relative detection efficiency (DE)]. The relative DE improves during each year in every region, and year-over-year improvement appears in both datasets. The reprocessed relative DE exceeds 40% throughout large portions of the study domain with relative maxima over the western Atlantic, eastern Pacific, and the Gulf of Mexico. The upgrade results in shorter distances between matched LIS and GLD360 locations, indicating improved location accuracy. On average, the matched LIS flashes last longer (18.6 ms) and are larger (379.3 km2) than the unmatched LIS flashes (6.1 ms, 251.0 km2). For each LIS characteristic examined, the greater the value, the more likely the GLD360 detects the flash. Of the matched LIS flashes, 44.3% have multiple GLD360 strokes, and the mean LIS characteristics increase with increasing stroke count. LIS flashes with four-plus related GLD360 strokes are longest (61.1 ms) and largest (492.7 km2). Of the multistroke flashes, 57.3% contain subsequent strokes that are stronger than the initial stroke. The vast majority of multistroke flashes with a first stroke estimated with a peak current of <10 kA have stronger subsequent strokes, suggesting that the GLD360 sometimes detects the initial cloud pulses associated with ground flashes. Grant no. NA14NES4320003