近57年山东省降水量及雨日变化特征

基于山东省1961—2017年21个气象站点的降水资料,采用线性回归、空间插值、滑动平均和小波分析等方法分析了57 a来山东省年、季降水量和雨日的时空变化特征。结果表明:山东省降水量和雨日整体呈现自南向北递减的纬度地带性和自东向西递减的经度地带性,高值中心都出现在泰山地区。春、夏两季的雨日和年雨日空间分布相似,冬季雨日呈“东北-西南递减型”分布;年降水量的减少速率为-16.28 mm/(10 a),年雨日以-2.16 d/(10 a)的速率显著下降(通过了0.05的信度检验),两者都存在约17 a的年代周期变化;春季降水量呈微弱增加趋势,和雨日趋势相反,其余三季的降水量和雨日都为负趋势,且夏季降水量和雨日的负趋势通过了0.05的信度检验。年尺度和季尺度下,雨日的负趋势都比降水量的负趋势强度要大,空间范围更广。研究成果可为山东地区水资源规划利用提供合理依据。

Characteristics of Climate Change in Precipitation and Rainy Days in Shandong Province in Recent 57 Years

According to the precipitation data of 21 meteorological stations from 1961 to 2017 in Shandong Province, we examined the spatial and temporal variations of yearly and seasonal precipitation and rainy days in Shandong Province via linear regression, spatial interpolation, moving average and wavelet analysis. Results unveiled that the precipitation and rainy days displayed a latitudinal zonal decline from south to north and a longitude zonal decrease from east to west in Shandong Province, with the high-value centering in the Mount-Tai area. The spatial distribution of rainy days in spring and summer was similar to that of annual rainy days, and the number of rainy days in winter distributed in a Northeast-Southwest decreasing trend. The number of annual rainy days dropped significantly at a rate of -2.16 d/(10 a) (passing 95% significance test), while the annual precipitation declined at a rate of -16.28 mm/(10 a), both in periodic change of about 17 a. The precipitation in spring showed a slight increase trend, which was opposite to the trend of rainy days. The precipitation and rainy days in the other three seasons were in negative trend; and particularly, the trend coefficient of precipitation and rainy days in summer passed 95% significance test. The negative trend of rainy days was stronger than precipitation and had a wider spatial range both on annual scale and on seasonal scale. The research findings provide a reasonable basis for water resources planning and utilization in Shandong.