摘要
利用1957-2006年全国679个测站逐日降水资料,针对不同年降水量的站点,定义了新的降水等级,分析了我国近50年不同强度降水的时空变化特征。结果表明:①不同等级降水占总降水量比重的分布,自西北向东南小雨量在总降水量中的分量逐渐下降,但小雨日数在总降水日数中依然是最主要的;中雨对年降水量的贡献在20%～38%;大到暴雨雨量和日数比重逐渐增加。②年降雨量及不同等级雨日数趋势表现为,在我国西部地区年降雨量及小雨、中雨日数呈正趋势,即在西部小雨、中雨雨日数增加的同时,西部年降水量亦在增加;而大-暴雨区主要集中在南方,华北、东北大-暴雨有不同程度的减少。③各气候区的突变检验结果为,甘新和青藏两个气候区年平均中雨日数增加趋势十分显著,而内蒙气候区在减少;华南区的年平均暴雨日数增加趋势明显。
The IPCC＇s Fourth Assessment Report was issued in 2007,in which it was pointed out that the precipitation in many regions in a zone of 30°-85°N was in a remarkable increased trend,but it was in a decrease trend in the low-latitude regions.As a result of global warning,the frequency and intensity of extreme climate events are in an obvious increase trend in many areas.Because of the land-sea thermal contrast and complex topography,the main land of China is subject to drought and flood almost every year.There is no obvious change of annual precipitation trend in China,but the regional characteristics of precipitation are significant.The inter-decadal variation of precipitations is closely related to severe drought and flood,and the anomaly of seasonal alternation of atmospheric circulation plays an important role in the occurrence of drought and flood.At the aspect of extreme precipitation,the trend of extreme precipitation in China in recent 50 years was researched by Zhai,et al.The conclusion reveals that extreme precipitation decreased significantly in north China and Sichuan Basin,but increased in west China,the Yangtze River Valley and southeast China.Some other studies suggest that the extreme precipitation days increased in northwest China and the middle-lower Yangtze Plain,but decreased in north China and some regions in south China.Annual,seasonal,and monthly precipitation can incompletely reflect the local precipitation status.Some researches found that the number of rainy days changes asynchronously with precipitation.Recent researches suggest that the annual and seasonal days of precipitation are decreasing significantly along with the decrease of precipitation.The researches on precipitation are different on precipitation intensity.Precipitation with different intensities plays an important role in daily life and routine production,so it is quite necessary to analyze the climatic statistical characteristics and variations of precipitation days and precipitation with different intensities.Based on the daily precipitation data from 679 stations in China during the period of 1957-2006,some new indexes were defined to analyze the spatial and temporal characteristics of precipitation with different intensities in China.The results are as follows：（1） Proportion of sprinkle in annual precipitation decreases significantly from northwest China to southeast China,but the proportion of sprinkle days in annual precipitation days is the highest;and the contribution rate of moderate precipitation to annual precipitation is relatively stable since recent 50 years,it fluctuates in a range from 20% to 38%,but it is less than 11% in Gansu-Xinjiang and Qinghai-Tibet regions and 11%-16% in other areas;the proportion of heavy precipitation in annual precipitation and the proportion of heavy precipitation days in annual precipitation days increase.（2） Analyses on the trends of annual precipitation and precipitation days reveal that all the sprinkle and moderate precipitation days as well as the annual precipitation increase in west China.The most significant increase is found in the eastern Tibet Plateau,while the decrease is detected in central and northeast China.（3） The correlation between the number of sprinkle or moderate precipitation days and annual precipitation decreases from the north to the south,but that between heavy rain and annual precipitation increases.The moderate rain days have increased significantly in Gansu-Xinjiang and Qinghai-Tibet climatic regions since the 1980s and increased in the 1960s respectively,the moderate rain days have decreased in Inner Mongolia climatic region since the 1990s.The heavy rain days in south China have been in an obvious increase trend since the 1970s,and the abrupt change occurred in 1971.The change of annual heavy-rain days is not significant in 4 climate regions including northeast China,north China,southwest China and central China.
出处
《干旱区研究》
CSCD
北大核心
2010年第5期766-772,共7页
Arid Zone Research
基金
国家科技支撑计划(2007BAC29B03
2009BAC53B02)资助
关键词
降水量
降水日数
降水强度
时空分布
中国
precipitation
precipitation day
precipitation intensity
spatial distribution
China.
