Contribution of precipitation events with different consecutive days to summer rainfall change over China

Abstract

The climatological features, regional trends, and interdecadal changes of summer precipitation over China are investigated in this study from the perspective of four types of precipitation events with different consecutive days. The precipitation events are classified based on the consecutive days of precipitation into 1-to-3-, 4-to-7-, 8-to-14-, and over-14-day events. The contribution of 1-to-3-day events to climatological precipitation is larger than the other events over central Asia. Longer duration events contributed more than the shorter duration events to precipitation in tropical regions. The positive precipitation trend in northwestern and southern China is mainly due to 4-to-7-day and 8-to-14-day events, respectively; and the negative precipitation trend in North China is largely related to 4-to-7-day events. In general, the frequency change of precipitation events is a major reason for the precipitation change of these events in the concerned regions. The precipitation decrease in northern China around the mid-1960s is attributed to the reduction in 4-to-7-day events. The precipitation increase in northeastern and central China in the late 1970s is due to a combination of increases in 4-to-7-day and 8-to-14-day events. The precipitation increase in southern China around 1993 is mainly contributed by over-14-day events. The precipitation decrease in the mid-latitude Asia is due to the decrease in 4-to-7-day events. Most of the interdecadal precipitation changes are related to decrease or increase in the activity of anomalous cyclones. Results suggest that the frequency of occurrence of cyclonic perturbations is a major factor for interdecadal changes in summer precipitation over China.