1988—2021年拉萨市城关区不透水面时空变化遥感监测

Study on the Temporal and Spatial Variation of Impervious Area of Chengguan District During 1988—2021

以拉萨市城关区为研究区,基于5期Landsat TM/OLI影像使用完全约束最小二乘混合像元分解法反演1988—2021年间城关区不透水面,分析了不透水面面积变化、分布特征和发展趋势。结果表明:(1)1988—2021年不透水面面积增长迅速,增速放缓;33年累计增长44.92 km2,增长率达480.1%;(2)不透水面发展方向性明显,由“西南—东北”向“西北—东南”转变,但整体呈“西—东”向分布;(3)不透水面重心发生移动,由5个时期不透水面加权平均重心可知,不透水面重心向东北方向移动,表明城关区城市发展重心正在向东部调整。

Based on the 5-phase Landsat TM/OLI imagery, the impervious area of Chengguan District from 1988to 2021 was inverted using the fully constrained least squares pixel decomposition mixture method, and the distri-bution characteristics, development trends as well as the variation of impervious area were analyzed. Our resultsare as follows:(1) From 1988 to 2021, the impervious area grew rapidly and then slowed down, and the cumula-tive growth rate within 33 years was found to be 44.92 km2, with a growth rate of 480.1%.(2) The orientation ofdevelopment of impervious area is obvious and is found to be shifted from southwest-northeast to northwest-southeast, however, the overall distribution shows west-to-east pattern.(3) Based on the weighted average centerof gravity of impermeable area within the 5-phase period, the center of gravity of impervious area is found to beshifted to the northeast, indicating that the center of gravity of urban development in Chengguan district is beingadjusted to the east.