摘要
利用1962年-2000年中国西北地区46个气象站点逐日降水量数据,以线性趋势分析、小波分析以及Mann-Kendall法为基础,对中国西北地区降水变化的时空特征进行了分析。分析结果表明:①近40年来年均降水量变化表现出一定的周期性,主要存在25年左右的年代振荡周期以及4年和9年左右的年际振荡周期;②降水空间分布呈现出由东南向西北逐渐减小的趋势,基本上呈连续分布。而新疆的塔里木盆地中部和东部以及吐鲁番盆地东部降水分布最少,并以此为中心向外扩展,平均降水量逐渐增加。降水增加区域主要分布于降水量较小区,降水减少的区域主要分布于降水量较高区,降水变化不明显区域则处于前两者之间的过渡区;③降水量少的地区降水增加趋势强烈,降水量偏多的地区降水减小趋势强烈。西北地区整体降水量并不是在下降,而是侧重于上升,以整个西北地区来讲上升幅度则很小。
Using daily precipitation data from 46 meteorological stations during the period 1962 to 2000 in northwestern China,and the linear trend analysis,wavelet analysis,as well as Mann-Kendall method,the authors investigated spatial and temporal characteristics of precipitation changes in northwestern China.Results indicated that over the past 40 years,in general,the precipitation fluctuated with a certain periodicity.There was a major oscillation period of 25 years,as well as an inter-annual oscillation period of approximately 4 years and 9 years.The slope of the linear regression showed that the precipitation over the northwestern regions as a whole decreased due primarily to a large geographic span of northwestern China,resulting in greater precipitation variability in eastern and western China.The precipitation error of each site was found to be larger on average;consequently it was not able to reflect details across the study region.To that end,the mean annual precipitation can only reflect a general trend over a large area,without reflecting the regional differences in the degree of fluctuation in precipitation.It was also found that the spatial distribution of precipitation showed essentially an incrementally decreasing trend from the southeast to the northwest.The least precipitation occurred at the central and eastern parts of the Tarim Basin in Xinjiang Uygur Autonomous Region,as well as the eastern part of the Turpan basin.The mean precipitation gradually increased from the center.The region where precipitation increased was principally distributed in areas with relatively less precipitation,whereas the region where precipitation decreased was mainly distributed over areas with more precipitation.The region with little precipitation change was observed to be in the transition zone of the first two regions.Areas with little precipitation exhibited a strong increasing trend,and areas with large precipitation showed a strong decreasing trend.In principle,the precipitation did not change significantly across the region between the former two transition zones.The precipitation in northwestern China as a whole has not decreased,but increased centered on some regions.The increasing rate of precipitation across the whole northwestern China tended to be particularly small.In terms of the age results of the interpolation of variability in precipitation,it was suggested that the overall precipitation in northwestern China did not decline,increasing to a small degree across the entire northwestern region.
出处
《资源科学》
CSSCI
CSCD
北大核心
2010年第12期2298-2304,共7页
Resources Science
基金
教育部人文社会科学重点研究基地项目(编号:2009JJD770025)
中央高校基本科研业务费专项资金(编号:GK200902023)
