基于轨迹变化探测的植被覆盖时空动态——以深圳大鹏半岛为例

基于ArcEngine组件二次开发,对1986—2007年密集时间序列的10期TM和ETM+遥感影像归一化植被指数(NDVI)变化轨迹进行探测,分析了深圳大鹏半岛快速城市化影响下植被覆盖变化的特征及成因.结果表明:1986—2007年,大鹏半岛植被覆盖动态主要类型包括稳定(a)、稳定-上升-稳定(aba)、稳定-下降-稳定(aca)和稳定-下降-稳定-上升-稳定(acaba),这4种类型的面积之和占研究区总面积的71.54%;类型a的分布最广,面积比例达1/3;类型acaba是研究区植被覆盖变化的代表类型,与20世纪90年代中期大规模毁林种果及之后的生态风景林建设等人为活动密切相关;海拔增高、坡度增大有效限制了人为活动的干扰强度,使植被覆盖动态复杂性降低;研究区植被覆盖的时序特征表现为,20世纪90年代中期明显下降和2003年之后显著上升.

Spatiotemporal dynamics of vegetation cover based on trajectory change detection:A case study in Dapeng Peninsula of Shenzhen

By using the second-time developed ArcEngine component at pixel level, this paper studied the spatiotemporal dynamics of vegetation cover in the Dapeng Peninsula of Shenzhen, China in 1986-2007, and analyzed the characters and causes of the dynamics. To quantify this dynamics, the NDVI changes in 1986-2007 were extracted from 10 time-series TM /ETM⁺ remote sensing images, and the results showed that from 1986 to 2007, there were four trajectories of vegetation cover change in the Peninsula, including stable (a), stable-rising-stable (aba), stable-descending-stable (aca), and stable-descending-stable-rising-stable (acaba). The area with these four types occupied 71.54% of the total. Among the four types, type “a” was most common, occupying 1/3 of the study area, mainly in the mountains; and type “acaba” was the typical one, which was closely related to the deforestation and reforestation after the human disturbances of original vegetation. The areas at higher elevation or steeper slopes exhibited smaller vegetation change, mainly because of the constrained human disturbances. Timing of the vegetation cover change showed a relative stability in the mid-90s of 20th century, but a dramatic change after 2003, coinciding with the growth of Shenzhen City.