黑河流域植被覆盖变化及其对地形的响应

Variations of Vegetation Coverage and Its Response to Terrain in Heihe River Basin

针对内陆河流域植被覆盖变化对地形响应研究不够深入的问题,利用趋势线模拟和Hurst指数等方法研究了2000-2015年黑河流域植被覆盖在地形上的分布规律和演化趋势,结果显示:1)植被覆盖随经度由西向东呈先增后减的趋势,随纬度增加亦呈先增后减趋势,在99°E～101°E经度带和37.4°N～38.5°N纬度带分布最广;2)植被覆盖在海拔1 500 m左右面积最大,在北坡向及坡度为0°～5°的平坦区域植被长势较好;3)近16年,植被NDV1年均值空间变化总体呈稳中向好的趋势,在1 000～1 500 m低海拔区植被变化明显,与人类活动有着紧密联系;在北坡和东北坡植被显著变化,不同坡度变化不明显;4)Hurst指数分析显示未来该区的植被覆盖存在一定的退化风险。

According to the influence of the different terrains on vegetation coverage changes in the inland river basins,combined with the methods of the trend line simulation, the Hurst index and others, the distribution and evolution trend of vegetation cover on the terrain was studied in Heihe river basin from 2000 to 2015. The results show： 1） The trend of the vegetation coverage changes first increased,and then decreased from west to east along the longitude,and it firstly increased,and then decreased along with the latitude. The vegetation is distributed in 99°E～101°E and 37, 4°N～38. 5° N. 2） The main vegetation coverage is at the altitude of 1 500 m,and the vegetation grow better in north direction and the slope of 0°～5°. 3）In the nearly 16 years, the vegetation NDVI changes appeared a good trend overall, and there were obvious changes on the low altitude area during 1 000～1 500 m,and it might be related to human activities closely. The vegetation changes occured mainly in the north and northeast,and the effect of slope was not obvious. 4）The analysis of the Hurst index shows that there will be still a certain degradation risk of the vegetation coverage in the future.