甘肃省40年来气温和降水时空变化

Spatial and Temporal Analysis on Annual Temperature and Precipitation During Last 40 Years in Gansu Province

  • 摘要: 对甘肃省1960—2003年气温和降水序列进行长期变化趋势分析的基础上,根据地统计学原理对20世纪60年代和90年代甘肃省气温和降水时空演变特征进行了探讨。结果表明:气温序列具有显著上升趋势;降水序列具有减少趋势,但不显著。20世纪60年代和90年代气温由空间自相关引起的空间变异分别占总空间变异的25%和32%,60年代和90年代降水由空间自相关引起的空间变异性分别占78%和80%。比较两个年代气温和降水的空间格局变化,甘肃省绝大部分地区气温升高,包括陇南南部、陇东、陇中东部、河西走廊平原区、北山山区的局部地区和祁连山区部分地区;除河西走廊平原区局部地区、北山中山区降水量有所增加外,大部分地区降水量有所减少。

     

    Abstract: Temporal features of annual temperature and precipitation at 28 stations in Gansu Province from 1960 to 2003 are analyzed using nonparametric Mann Kendall method and the accumulated departure approach. Spatial characteristics of these two variables in the 1960s and 1990s are detected using geostatistical method. It shows that the annual temperature has a significant increasing trend, while the precipitation has an insignificant decreasing trend at 0.1 significance level. Annual temperature experienced with low level from the 1960s to mid 1980s and with high level from 1986 to 2003, and abundant precipitation occurred in the 1970s and relative low in the 1990s at 0.05 significance level. Gaussian model is the best theoretical model for temperature semivariogram. 25% and 32% of total spatial variability in temperature is resulted from spatial autocorrelation in the 1960s and 1990s. Spherical model is the best model for precipitation semivariogram. The incidence of precipitation in the 1990s is smaller than that in the 1960s, and smaller than those of temperature in both 1960s and 1990s, indicating that the effects of local micro climate such as topography and slopes on precipitation is greater than those on temperature. 78% and 80% of total spatial variability in precipitation is attributed to spatial autocorrelation in the 1960s and 1990s, showing intensive spatial autocorrelation in precipitation in Gansu Province. Compared with the spatial variations from 1960s to 1990s, temperature increased in most of the regions, including the south of Longnan, Longdong, the east of Longzhong, Hexi Corridor plain, local area of Beishan middle mountains and the Qilian Mountains area. Precipitation tended to decrease in most of the regions, especially in Longnan area and Gannan Plateau area, while the situations in some local areas of Hexi Corridor plain and Beishan middle mountains area are on the contrary.

     

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