1961—2014年北疆地区降水时间演变特征分析

Time Evolution of Precipitation Characteristics in Northern Xinjiang

利用北疆地区15个县市1961-2014年逐日降水资料,采用数理统计、一元线性回归、小波变换分析等方法,研究了北疆地区年平均降水量年际变化、年平均降水量距平变化、月降水量变化特征以及中雨日数、大雨日数、极端降水日数变化规律,得出以下结论:(1)对年平均降水量年际变化规律分析得出,北疆地区年平均水量呈逐年递增趋势,降水量倾向率约为12 mm/10年,年平均降水量每10年增加12 mm;(2)通过年平均降水量距平变化分析得出,1961-1985年期间年平均降水量较少,从1998年开始北疆地区年降水量高于平均值水平,降水量相对偏多;(3)通过对1月、4月、7月、10月这4个代表月降水量变化分析得出,4个月份逐年的月降水量均呈递增趋势,其中7月份降水量递增幅度最大,降水量倾向率约为21.7 mm/10年;(4)通过对极端降水变化规律分析得出,北疆地区中雨日数呈逐年递增趋势,每10年增加5 d左右,大雨日数每10年增加1 d左右,极端降水日数每10年增加6 d左右;(5)通过小波变换分析得出,年平均降水时间序列在年际演变过程中,存在2~4年的小尺度、4~8年的中尺度、8~16年的大尺度的周期变化规律;(6)对代表月降水量数据M-K突变检验分析得出,1986年为1月份、7月份降水量的一个突变年,1975年、1984年为4月份降水量的2个突变年,1985年为10月份降水量的一个突变年。

In this paper,daily precipitation data of 15 counties from 1961 to2014 were used,and mathematical statistics,linear regression method,wavelet transform analysis were adopted to study the average annual precipitation,annual average precipitation anomaly a variety of characteristics and the number of moderate days,heavy rain for several days,extreme changes in precipitation patterns,the representative of the number of monthly precipitation in Northern Xinjiang,the following conclusions:(1) the average annual precipitation variation analysis showed the average water year increasing trend,precipitation trend rate of about 12 mm/10 years,the average annual precipitation per decade 12 mm;(2) by the average annual rainfall anomaly change analysis concluded that in 1961,less the average annual precipitation for the period 1985,since 1998 the average annual precipitation in northern areas than the level of rainfall is relatively high side;(3) by January,April,July,October is the month that four changes in precipitation analysis results,four months each year of monthly precipitation showed an increasing trend,which increments the biggest rainfall in July,rainfall trend rate of about 21.7 mm/10 years;(4) by extreme rainfall variation analysis concluded that the northern region rain day number was increasing in recent years,increasing every 10 years about 5 days of heavy rain a few days per decade about 1 day,extreme precipitation days per decade about 6 days;(5)wavelet transform analysis concluded that the average precipitation time series interannual evolution,there are 2~4 years,small-scale,4 ~8 year scale,8 ~16 years of changing patterns of large scale;(6)According to the m-k mutation test of representative monthly precipitation data,1986 is a mutation year of precipitation in January and July;1975 and 1984 are two mutation years of precipitation in April;1985 is a mutation year of precipitation in October.