Climatology of Hail Frequency and Size in China, 1980–2015

Abstract

AbstractThe hail day climatology from 1961 to 2005 was previously studied based on hundreds of surface stations in China. Recently, both hail occurrence and maximum hail diameter (MHD) data from more than 2000 surface stations were released by the National Meteorological Information Center of China. These data enable hail climatology to be explored using both hail frequency (HF), which is defined as annual mean hail occurrence, and MHD records from more stations over the entire country. Following quality control, hail data from 2254 stations were selected for the period of 1980–2015. In general, HF increased with station topography height, with a maximum of more than 30 events per year in the Tibetan Plateau and a minimum of less than 1 event per year in southern China, whereas the station mean MHD decreased with topography height. The highest peak of the 80th-percentile cumulative distribution function of the annual MHD cycle in southern China occurred in May but was delayed to July in the north. Severe hail (MHD ≥ 20 mm; 5.32% of all cases) mainly occurred along the edge of the plain, near the mountainsides, and was most likely to develop in the afternoon.