吐鲁番地区暖季降水时空分布特征

摘要

以吐鲁番5个国家气象站近55 a(1960—2014年)与26个区域气象站近3 a(2013—2015年)逐小时降水资料为基础,利用Pearson相关分析、气候倾向率、Mann-Kendall突变分析、Morlet小波分析等方法,分析了吐鲁番地区暖季降水时空分布特征,并就地形对吐鲁番降水的影响进行了量化研究.结果表明:在新疆趋暖趋湿的气候背景下,吐鲁番盆地平原区和山区存在截然不同的降水时空变化特征,吐鲁番地区降水高度集中在暖季,且暖季山区降水集中度和稳定性更好;暖季盆地内存在频率>55％的夜雨区和昼雨区,盆地西南坡地和腹地平原区为夜雨区,盆地北部天山山区降水则集中在午后,海拔高度大约每增加(减少)300 m,降水集中时段提前(延后)1h.研究还表明,吐鲁番降水与地形关系密切,海拔高度是影响吐鲁番降水的决定性因素,其暖季降水量、降水时数均与海拔高度呈显著正相关,降水量增加的主要原因是降水时数随海拔高度的递增;降水量随海拔高度的变化呈二次曲线型,其最大降水高度为1900 m;在最大降水高度以下,降水量由盆地腹地的平原区向山区递增,降水垂直变率平均为6.2 mm/100 m,其中1500～1900 m高度是降水量与降水垂直变率最大的区域,降水垂直变率达20 mm/100 m.%Hourly precipitation records from 5 national weather stations for 1960-2014 and 26 regional weather stations for 2013-2015 in the Turpan Basin are used to investigate the temporal and spatial distribution characteristics of warm season precipitation in Turpan ragion, by applying a suite of statistic methods including Pearson correlation analysis, climate tendency rate analysis, Mann-Kendall test, Morlet wavelet analysis. The impacts of topography on precipitation in the Turpan are also quantified. Our results show that against the climatic background of warmer and wetter in Xinjiang, the temporal and spatial distribution characteristics of precipitation between plain regions and mountain regions in Turpan basin are distinctive. Precipitation in the Turpan is highly concentrated in the warm season, and precipitation is more intense and stable in mountain regions. There are regions in the basin with the frequency of nocturnal and rainy days larger than 55％during the warm season, and the southwest slope and plain are the nocturnal rain regions. The precipitation in the northern mountain area mainly occurs in the afternoon, and concentrated precipitation period varies obviously with altitude,the average vertical variability of concentrated precipitation period is 1 h/300 m.The results also show that precipitation in the Turpan is closely related to topography, and the terrain height is the dominant factor for precipitation. The amount and hours of warm season precipitation in the Turpan are significantly correlated with the elevation. The increased precipitation amount is mainly due to the increase in precipitation hours. The maximum precipitation height is 1900 m and below this height precipitation increases from the plain to the mountain area, and the average vertical variability of precipitation is 6.2 mm/100m.Heights ranging from 1500 m to 1900 m are the area where the amount and vertical variation(up to 20 mm/100 m)of precipitation are the largest.