Spatiotemporal Characteristics of Summer Precipitation with Different Durations in Central East China

Based on the dataset of hourly rain gauge records in central East China for the period 1961-2012, the spatiotemporal characteristics of summer rainfall events in terms of their durations are analyzed. The results show that the rainfall duration exhibits a short-long-short meridional pattern in central East China, i.e., short-duration rainfall events (1-6 h) prevail in southern and northern China, whereas long-duration rainfall events (>6 h) contribute more than 60% to the total rainfall in the region between about 28°N and 37°N. As the duration increases, the occurrence of light rainfall events with intensity weaker than 1 mm/h decreases, while the occurrence of moderate rainfall events with intensify between 1.1 mm/h and 10.0 mm/h increases. Rainfall events with intensity stronger than 10.0 mm/h tend to be characterized by relatively short duration in the region south of about 35°N. The total summer rainfall amount increases in southern China due to the increasing trends of both intensity and occurrence, and decreases in northern China with decreasing occurrence but increasing intensity. The rainfall duration generally shows an increasing trend in central East China, especially in the region between the Yangtze River and Yellow River. The significant increase of total rainfall amount in this region from the late 1970s to early 1990s is mainly attributed to the increase of long-duration rainfall amount, while no obvious interdecadal abrupt change is detected in the short-duration rainfall amount. The significant increase of total rainfall amount in southern China after the early 1990s is related to both the increase of long-duration and short-duration rainfall amount, but the impact of the former is more wide-ranging and northward.