摘要
采用1968—2007年全国595个气象台站的日降水资料,将降水量分为0.1～9.9 mm、10～24.9 mm、25～49.9 mm和≥50 mm共4个不同量级降水,通过趋势系数等统计诊断方法,分析了年雨日与年降水量相关性、年雨日与日平均降水强度的变化趋势、不同量级降水的日数和强度的变化趋势以及它们分别对年降水量变化的影响。结果表明:1)年雨日与年降水量的相关性降低,而日降水强度与年降水量的相关性却越来越强,这些变化在20世纪80年代尤为明显。2)中国除了新疆、西藏东部、青海和四川西部的年雨日呈现增加趋势外,其余大部分地区呈现减少趋势;日降水强度在华中、华东、华南、东北和西部的部分地区呈现增加趋势,其余大部分地区没有明显的变化趋势;年降水量在西北西部、西南西部、江淮流域、长江三角洲和东南沿海城市呈现增加趋势,而在西北东部、西南东部、华南西部、东北南部和华北呈现减少趋势。3)年降水量减少的区域,降水量的变化主要是由于降水日数减少引起的;年降水量增加的区域,降水量的变化与降水日数和强度都有一定的关系。
Based on daily precipitation during the period of 1968 -2007 at 595 meteorological stations in China divided to four different precipitation classes ranging from 0.1 - 9.9 mm, 10 -24.9 mm, 25 49.9 mm to over or equal to 50 mm, the similarity relationship between annual rainy days and annual precipitation, the tendencies of annual rainy days and daily average precipitation intensity, the tendencies of rainy days and precipitation intensities in different classes and their effects on the change of annual precipitation amounts were analyzed respectively by using statistical diagnostic methods such as the trend coefficients. The results are as follows. 1 ） Similarity relationship between annual rainy days and annual precipitation decreased and had a significant shift around 1980s, that＇ s to say, the annual precipitation became more related to daily average precipitation intensity since then. 2） Annual rainy days in China except Xinjiang, Eastern Tibet, Qinghai and the western of Sichuan appeared increased, most of the rest of the region decreased. Daily precipitation intensity in Middle China, Eastern China, Southern China, Northeast China and part of Western China appeared increased while other regions no obvious variations. Annual precipitation in the western of Northwestern and Southwestern China, the Yandtze-Huaihe valley, Yangtze River delta and Southeastern Coast China increased while the eastern of Northwestern and South- western China, the western of Southern China, the southern of Northeastern China and Northern China decreased. 3） The changes of annual precipitation were mainly caused by the rainy days for the areas whose annual precipitation decreased, while the changes of annual precipitation were caused by both the rainy days and precipitation intensities for the areas whose annual precipitation increased.
出处
《气象与环境科学》
2011年第4期7-13,共7页
Meteorological and Environmental Sciences
基金
公益性行业(气象)专项"设施农业及特色农产品气象保障关键技术研究"项目(GYHY200906023)资助
关键词
年降水量
降水日数
降水强度
annual precipitation
rainy days
precipitation intensity
