Global Frequency and Geographical Distribution of Nighttime Streamer Corona Discharges (BLUEs) in Thunderclouds

Blue LUminous Events (BLUEs) are transient corona discharges occurring in thunderclouds and characterized by strong 337.0 nm light flashes with absent (or weak) 777.4 nm component. We present the first nighttime climatology of BLUEs as detected by the Modular Multispectral Imaging Array of the Atmosphere-Space Interaction Monitor showing their worldwide geographical and seasonal distribution. A total (land and ocean) of similar to 11 BLUEs occur around the globe every second at local midnight and the average BLUE land/sea ratio is similar to 7:4. The northwest region of Colombia shows an annual nighttime peak. Globally, BLUEs are maximized during the boreal summer-autumn, contrary to lightning which is maximed in the boreal summer. The geographical distribution of nighttime BLUEs shows three main regions in, by order of importance, the Americas, Europe/Africa and Asia/Australia.

Automated summary

BLUEs are transient corona discharges in thunderclouds with strong 337.0 nm light flashes. A total of about 11 BLUEs occur globally every second, with a nighttime peak in the northwest region of Colombia and a global peak in the boreal summer-autumn. The geographical distribution of nighttime BLUEs shows three main regions: the Americas, Europe/Africa, and Asia/Australia.