黑河流域上游降水精细化分布与总量年际变化

The Elaborate Distribution of Precipitation and Interannual Variation of Total Precipitation in the Upstream of the Heihe River

利用黑河流域100m×100m地理地形资料及气象测站多年降水和风向资料,依据坡度、盛行风向与迎风坡对地形抬升速度影响的数学模式,对主导风向效应指数进行了扩展,构建了新的耦合坡度、坡向和主导风向的局地地形因子.通过回归分析,建立了逐年6—9月降水量与地理和局地地形因子的回归方程,通过GIS空间分析技术扩展得到了黑河流域上游1967—2008年逐年6—9月降水量的空间精细化分布,基于此计算了降水总量并分析其年际变化.结果表明:构建的局地地形因子与黑河流域逐年6—9月降水量均有很好的相关关系.逐年6—9月降水量与地理和局地地形因子的回归方程能够很好地拟合上游降水量,尤其在70年代末期以后拟合值与实测值基本吻合,多年平均相对误差在10%以内.在降水量空间精细化分布基础上计算的黑河流域上游多年平均6—9月降水总量为98.2×108 m3,降水总量具有明显的年际变化,1982年之前降水总量呈上升趋势,1982—2000年间波动幅度较大,2000年以来具有明显的上升趋势,整体趋势呈微弱上升.

Using the geographical and topographic data with the resolution of 100 m×100 m and the meteorological observation data including precipitation and wind,in this paper,a new local terrain index of coupling slope,aspect and prevailing wind direction was constructed firstly based on the effect of prevailing wind direction and windward slope on precipitation,proposed by Fu Bayou,and the prevailing wind direction effect index,established by Sun Pengsen.The new index has more clear physical meanings of atmosphere-earth interaction.Then regression equations between precipitation from June to September and geographical and topographic factors were established by means of regression analysis year after year（1967—2008）.According to the regression equations,the space elaborate distribution of precipitation from June to September can be obtained by spatial analysis year after year in the upstream.On this basis,the total precipitation can be calculated year after year in this area.The result showed that there were very good correlations between the new local terrain index and precipitation from June to September year after year.Cross test results showed that the regression equations can fit well the upstream precipitation.Especially since the late 1970s,the fitted values have been very close to the measured values.The average relative error was less than 10%.Based on the space elaborate distribution of the precipitation,the mean total precipitation from June to September was calculated to be about 98.2 billion m3 in the upstream of the Heihe River.The total precipitation had obviously interannual variation with a slight rising tendency.Before 1982,the total precipitation showed an ascendant tendency.During 1982 to 2000,the total precipitation fluctuated large.Since 2000,the total precipitation has increased obviously.