The WGLC global gridded lightning climatology and time series

Abstract

Lightning is an important atmospheric phenomenon and has wide-ranging influence on the Earth system, but few long-term observational datasets of lightning occurrence and distribution are currently freely available. Here, we analyze global lightning activity over the second decade of the 21st century using a new global, high-resolution gridded time series and climatology of lightning stroke density based on raw data from the World Wide Lightning Location Network (WWLLN). While the total number of strokes detected increases from 2010–2014, an adjustment for detection efficiency reduces this artificial trend. The global distribution of lightning shows the well-known pattern of greatest density over the three tropical terrestrial regions of the Americas, Africa, and the Maritime Continent, but we also noticed substantial temporal variability over the 11 years of record, with more lightning in the tropics from 2012–2015 and increasing lightning in the midlatitudes of the Northern Hemisphere from 2016–2020. Although the total number of strokes detected globally was constant, mean stroke power decreases significantly from a peak in 2013 to the lowest levels on record in 2020. Evaluation with independent observational networks shows that while the WWLLN does not capture peak seasonal lightning densities, it does represent the majority of powerful lightning strokes. The resulting gridded lightning dataset (Kaplan and Lau, 2021a, https://doi.org/10.5281/zenodo.4774528) is freely available and will be useful for a range of studies in climate, Earth system, and natural hazards research, including direct use as input data to models and as evaluation data for independent simulations of lightning occurrence.