Huangjie Kong, Li Cai, Wenchao Fan, Jianguo Wang, Jinxin Cao, Mi Zhou, Yadong Fan
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引用次数: 0
Abstract
This article harnesses data from the Lightning Imaging Sensor (LIS) to explore global diurnal cycles of lightning (DCL) spanning the period from 1998 to 2015. Lightning parameters—frequency, radiance, and footprint—were standardized to a 0.5° × 0.5° resolution grid and segmented into distinct diurnal patterns using the Bisecting K-Means algorithm. Across these patterns, significant differences emerge between ocean and land lightning activity. Globally, lightning frequency demonstrates a unimodal variation, reaching a peak at 16:00 and a valley at 10:00, driven by solar heating of the landmass and contributed to predominantly by lightning over land. The land/ocean frequency ratio shifts dynamically throughout the day, ranging from 0.70 to 11.36. Ocean lightning consistently shows higher radiance and footprint than land. The ocean/land radiance and footprint ratio follow a similar diurnal trend as frequency, ranging from 1.33 to 2.22 and from 1.16 to 1.39, respectively. Clustering analysis underscores the contrasting dynamics of land and ocean, with ocean lightning concentrated during nighttime hours, while land lightning peaks in the afternoon and evening. Transitional zones with distinct clusters are observed along the coastline. Furthermore, DCLs reveal differences across the three lightning parameters: frequency trends are more temporal concentrations, whereas radiance and footprint clusters span broader time periods. DCLs exhibit pronounced spatial heterogeneity across latitude, distance from coastline, and elevation. The clustering patterns shift at different critical latitudes for each parameter, with hemispheric asymmetry in distribution patterns. Clusters exhibit distinct distance-variation patterns over land and ocean, with nocturnal activity patterns becoming dominant with increasing elevation. This study fills a pivotal gap in global DCL research and provides important clues for studying lightning mechanisms, thereby contributing to the development of effective global lightning protection strategies.
期刊介绍:
The journal publishes scientific papers (research papers, review articles, letters and notes) dealing with the part of the atmosphere where meteorological events occur. Attention is given to all processes extending from the earth surface to the tropopause, but special emphasis continues to be devoted to the physics of clouds, mesoscale meteorology and air pollution, i.e. atmospheric aerosols; microphysical processes; cloud dynamics and thermodynamics; numerical simulation, climatology, climate change and weather modification.