Changes in seasonal patterns of temperature and precipitation in China during 1971–2000

摘要

Many studies have shown evidence for significant changes in surface climate in different regions of the world and during different seasons over the past 100 years. Based on daily temperature and precipitation data from 720 climate stations in China, cluster analysis was used to identify regions in China that have experienced similar changes in the seasonal cycle of temperature and precipitation during the 1971–2000 climate normal period. Differences in 11-day averages of daily mean temperature and total precipitation between the first (1971–1985) and second (1986–2000) halves of the record were analyzed using the Mann-Whitney U test and the global k-means clustering algorithm. Results show that most parts of China experienced significant increases in temperature between the two periods, especially in winter, although some of this warming may be attributable to the urban heat island effect in large cities. Most of western China experienced more precipitation in 1986–2000, while precipitation decreased in the Yellow River valley. Changes in the summer monsoon were also evident, with decreases in precipitation during the onset and decay phases, and increases during the wettest period.