陕西省近47a来降水变化分析

利用陕西省78个气象观测台站1961—2007年逐日降水量资料,分析了陕西地区降水变化特征及其对旱涝的影响。结果表明,47a来陕西地区的年降水量呈明显的减少趋势,减少幅度为18.4mm/10a,主要表现为春秋季降水的减少;降水日数的变化呈减少趋势,递减率为3.2d/10a,主要体现在小雨和中雨事件频率的下降;但是平均降水强度总体呈微弱的增强趋势,主要原因是大雨和暴雨频次的增加。在显著变暖的20世纪90年代以后,雨日减少,但暴雨增多,强度增强,该区域降水有向不均衡、极端化发展的趋势,旱涝灾害也有加重趋势。

Analyses of Precipitation Change in Shaanxi Province during 1961-2007

Based on the daily precipitation data from 78 stations in Shaanxi during 19612007,the spatial and temporal distributions of precipitation amount,frequency and are analyzed.The main conclusions are as follows:The annual precipitation decreased by a rate of 18.4 mm per 10 years,being manifested by precipitation decrease in spring and autumn;The annual rainy days had a significantly decreasing trend at a rate of 3.2 days per 10 years,which was mostly due to the decrease of light and middle rain events;The inte...