黑河中上游地区最高、最低气温非对称变化的时空特征分析

Change of Maximum and Minimum Temperature in the Middle Region of Heihe Basin

运用气候倾向率、趋势系数法、复值Morlet小波及Mann-kendall突变检测等方法,对黑河中上游地区1960—2009年最高、最低气温非对称变化的时空特征进行了分析.结果表明,近50a来,年和四季的平均最高、最低气温均呈明显增温趋势,最低气温空间上表现为由西北向东南方向依次递增,最高气温在流域东部和西南部为强增温区.年平均最高气温变化的突变点为1994年,最低气温变化的突变点为1989年.黑河中上游地区最高气温年变化具有明显的14a振荡周期,而最低气温主振荡周期为12a.

This paper analyzed the temporal and the spatial characteristics of the maximum and the minimum temperature changes in the Middle Region of Heihe River Valley, using Morlet wavelet analysis and Mann-kendall methods. The results show that the annual and the seasonal mean maximum and minimum temperature of all exhibited an increasing tendency during the past 50 years. The maximum and the minimum temperature increased most markedly in winter. The seasonal trends of the maximum and the minimum temperature change exhibited a spatial variation. The minimum temperature in winter change from northwest to southeast increased by latitudes, but the maximum temperature in the east and southwestern district of the river basin increased clearly. The annual mean maximum temperature began obvious warming from 1990s, the sudden change was similar to the minimum temperature. The sudden change of the annual mean maximum temperature betided 1994, and the minimum temperature occurred in 1989. The minimum temperature change in Heihe River Valley in the Middle Region of Hexi Corridor demonstrated oscillation characteristics with clear 14-year cycles and the minimum temperature showed an obvious 5-year cycle, and exhibited inter-decadal variation.