Spatiotemporal Characteristics of Precipitation Concentration and Their Linkage to Temperature Over China

Abstract

Precipitation concentration represents the temporal unevenness of precipitation over a given period. A higher concentration increases the likelihood of concurrent flooding and drought. While previous studies have primarily focused on precipitation concentration at the daily scale, research on sub-daily scales remains limited. Furthermore, the impact of temperature on precipitation concentration across various temporal scales is not well understood. In this study, we utilise high-resolution precipitation products and the Gini index (GI) to examine the spatiotemporal characteristics of precipitation concentration across four different time scales (3, 6, 12-h and 1-day) over China. The climatological analysis reveals a gradual increase in precipitation concentration from southeast to northwest China. At shorter temporal scales (3 and 6-h), Southeastern China exhibits a notable increase in precipitation concentration, while longer scales (12-h and 1-day) show a significant decrease throughout most regions of Northwest China. These observed spatiotemporal patterns are closely linked to temperature variations. At the 3-h scale, precipitation concentration at the 3-h scale increases with temperature at a nation-averaged rate of 1.06% °C⁻¹ and decreases to 0.30% °C⁻¹ at the 1-day scale. Higher temperatures intensify precipitation concentration at the 3-h scale in Southeast China by increasing the frequency of heavy precipitation events. Meanwhile, in Northwest China, the decline in concentration at the daily scale under warmer conditions is attributed to increased annual precipitation amounts driven by higher temperatures. This study is of great significance, as it provides insight into how the temporal distribution of precipitation in China change under future global warming.