17 August 2003, in final form 5 August 2004 | PANMAO ZHAI, XUEBIN ZHANG, HUI WAN, XIAOHUA PAN
This study examines trends in total precipitation and extreme precipitation events in China from 1951 to 2000 using a newly developed daily precipitation dataset of 740 stations. The analysis reveals that while there is little overall trend in total precipitation, regional and seasonal patterns are distinct. Annual total precipitation has decreased in southern northeast China, north China, and the Sichuan Basin, but increased in the Yangtze River Valley and the Yellow River Basin. In western China, both cold and warm seasons show significant precipitation increases. Eastern China exhibits contrasting trends, with spring precipitation increasing in southern northeast and north China, but decreasing in the mid-reach of the Yangtze River. Summer precipitation trends are similar to those of annual totals, while autumn precipitation has generally decreased throughout eastern China. Winter precipitation has significantly decreased in northern China but increased in the south. The number of rain days has decreased across most of China, except in the northwest, while precipitation intensity has increased. This suggests that the increase in western China is due to both increased frequency and intensity. In eastern China, the increase in rain days is more dominant in the north, while enhanced intensity prevails in the south. Regions with negative precipitation trends have experienced higher-than-normal frequency of extreme events, particularly in western China, the mid-lower reaches of the Yangtze River, and parts of southwest and south China. The connection between changes in total and extreme precipitation is explored, showing that trends in the number of extremes and total precipitation from nonextreme events are generally in phase, except in southwest China where an increase in extreme events is associated with a decrease in total nonextreme precipitation.This study examines trends in total precipitation and extreme precipitation events in China from 1951 to 2000 using a newly developed daily precipitation dataset of 740 stations. The analysis reveals that while there is little overall trend in total precipitation, regional and seasonal patterns are distinct. Annual total precipitation has decreased in southern northeast China, north China, and the Sichuan Basin, but increased in the Yangtze River Valley and the Yellow River Basin. In western China, both cold and warm seasons show significant precipitation increases. Eastern China exhibits contrasting trends, with spring precipitation increasing in southern northeast and north China, but decreasing in the mid-reach of the Yangtze River. Summer precipitation trends are similar to those of annual totals, while autumn precipitation has generally decreased throughout eastern China. Winter precipitation has significantly decreased in northern China but increased in the south. The number of rain days has decreased across most of China, except in the northwest, while precipitation intensity has increased. This suggests that the increase in western China is due to both increased frequency and intensity. In eastern China, the increase in rain days is more dominant in the north, while enhanced intensity prevails in the south. Regions with negative precipitation trends have experienced higher-than-normal frequency of extreme events, particularly in western China, the mid-lower reaches of the Yangtze River, and parts of southwest and south China. The connection between changes in total and extreme precipitation is explored, showing that trends in the number of extremes and total precipitation from nonextreme events are generally in phase, except in southwest China where an increase in extreme events is associated with a decrease in total nonextreme precipitation.