黄河流域上中游地区土地利用变化的降水效应

Precipitation Effects of Land Use Change in the Upper and Middle Reaches of the Yellow River Basin

土地利用变化影响着流域的降水过程,确定土地利用和降水的关系有利于指导区域空间规划,构建区域生态安全。研究利用土地利用时空转移矩阵和标准差椭圆分析方法,对1985—2015年的土地利用数据和8 km降水数据进行详尽分析。结果表明,1985—2015年黄河流域上中游地区耕地和湿地面积呈下降趋势,森林、不透水地面和草地面积呈上升趋势;年均降水量呈上升趋势,一年四季降水呈分异趋势。利用GIS绘制的7月最大降水量中心标准椭圆呈从大到小的变化趋势,表明降水呈集中化趋势;不透水地面几何中心分布呈现较好的线性关系,但7月降水中心线性关系不明显。土地利用和降水的相关系数表明,影响降水的土地利用类型的重要性排序依次为湿地>荒地>不透水地面>森林>草地>耕地>雪/冰>水体>灌木林。

Land use change affects the precipitation process of the basin.Determining the relationship between land use and precipitation is conducive to guiding regional spatial planning and building regional ecological security.In this study,the land use data and 8km precipitation data from 1985 to 2015 were analyzed in detail by using the land use time-space transfer matrix and the standard deviation ellipse analysis method.The results showed that the area of cultivated land and wetland in the upper and middle reaches of the Yellow River basin showed a downward trend,while the area of forest,impervious ground,and grassland showed an upward trend.The average annual precipitation showed an upward trend,and the precipitation showed a different trend throughout the year.The central standard ellipse of maximum precipitation in July plotted by GIS showed a trend from large to small,indicating that precipitation showed a concentrated trend.The geometric center distribution of impervious ground showed a good linear relationship,but the linear relationship of precipitation center in July is not obvious.The correlation coefficient between land use and precipitation showed that the order of importance of land use types affecting precipitation was wetland>wasteland>impervious ground>forest>grassland>cultivated land>snow or ice>water body>shrubbery.