三江源地区1961−2019年降水量时空变化特征

Spatiotemporal variations in precipitation in the Three-River Headwater region from 1961 to 2019

利用三江源地区13个气象站1961−2019年共59年的降水量资料,基于一元线性回归、滑动平均法、气候倾向率和重标极差分析等方法,研究源区降水量的时空演变规律和未来变化趋势。结果表明:三江源地区年均降水量为470.7 mm,并以10.31 mm·10 a^(−1)的速率增加。黄河源区春季降水量最大,其余三季以澜沧江源区最高,长江源区四季均处于最低值;各源区降水量均呈增加趋势,其中春季降水倾向率最大,长江、黄河和澜沧江源区分别为2.69、2.11和2.80 mm·10 a^(−1)。1961−2002年降水量累积距平大致呈下降趋势,2003−2019年呈上升趋势,2002年为降水增加突变点;不同年代际间平均年最大和最小降水量出现在2011−2019和1961−1970年,分别为512.82和452.23 mm。年、季降水量自西北向东南递增,黄河源区各站点降水量空间变化幅度最大;春、夏、秋三季的降水倾向率呈现出由西北向东南减少的趋势,但冬季变化相反,且降水量少的源区降水增加趋势明显。降水量长程变化Hurst值大于0.5,预测未来降水量变化与过去趋势一致。三江源地区降水时间和空间序列变化具有明显的区域和季节差异性特征,且未来降水呈增加趋势。

This study analyzed the spatiotemporal pattern of precipitation and its future trends in the Three-River Headwater region using the linear regression,moving average,climate trend rate,and recalibration range methods with 59 years(1961-2019)of precipitation data.The data were taken from 13 meteorological stations in the Three-River Headwater region.The results indicated that the average annual precipitation was 470.7 mm in this region and had an increasing trend of 10.31 mm·10 a^(−1).The Yellow River had the highest precipitation in spring,the Lancang River had the highest precipitation in the other three seasons,and the Yangtze River had the lowest precipitation in all four seasons.Precipitation in all source regions showed an increasing trend,and the greatest climatic trends in the rate of precipitation,which was seen in spring,were 2.69,2.11,and 2.80 mm·10 a^(−1) for the Yangtze,Yellow,and Lancang rivers,respectively.The cumulative precipitation anomaly showed decreasing trends from 1961 to 2002 and an increasing trend from 2003 to 2019.Catastrophic precipitation occurred in 2002.The average annual minimum and maximum precipitation in different years occurred in the periods 1961-1970 and 2011-2019 and were 452.23 and 512.82 mm,respectively.Annual and seasonal precipitation increased from northwest to southeast,and the range in the spatial variation in precipitation was greatest in the Yellow River source region.The climatic trends in precipitation rates during spring,summer,and autumn decreased from northwest to southeast,but the opposite was observed during winter;this indicated that precipitation increased strongly in source regions with less precipitation.The Hurst value of the long-term change in precipitation was larger than 0.5,indicating that future changes in precipitation would be consistent with past trends.A spatiotemporal pattern in precipitation was observed in the Three-River Headwater region,where future precipitation will present an increasing trend.