成都平原及其周边区域植被覆盖动态监测

利用Landsat TM/OLI遥感数据、DEM和地貌数据,基于像元二分模型、遥感与GIS技术对2007~2013年成都平原及周边区域的植被覆盖动态变化进行了估算,并结合高程、坡度、坡向和地貌数据,定量分析了汶川地震前、后植被受损与恢复的空间动态格局变化。研究表明:(1)植被覆盖总体良好,近一半区域的植被覆盖度均在中、高度以上,空间格局上呈现由西部的龙门山区向中部的平原区域降低的总体趋势;(2)地震造成植被受损面积约6.91×105 hm~2,集中分布于海拔324~800 m、坡度20°、东坡、南坡和西坡及山地地貌部位;(3)震后5 a,植被恢复面积约4.88×105 hm~2,主要分布海拔324~1 000 m、坡度30°、平缓坡、南坡、东坡和西坡、丘陵和大起伏山地以下区域;(4)高程、坡度和地貌对植被损毁与恢复的影响明显高于坡向。

Dynamic Monitoring of Fractional Vegetation Cover of Chengdu Plain and Its Surrounding Area in China

Information of fractional vegetation cover (FVC) of Chengdu Plain, China and its surrounding area during 2007-2013 were extracted and analyzed based on Landsat TM/OLI data, DEM, geomorphology data and GIS technology following the dimidiate pixel model. The differentiation characteristics of the spatial and temporal dynamic patterns of FVC, vegetation damage caused by the Wenchuan Earthquake, and vegetation restoration were also quantitatively studied based on data of the elevation, slope, aspect, and geomorphology. Results show as in the following 4 aspects. (1) Vegetation coverage had become generally good during the study period. There were variations in levels of FVC, and the FVC in nearly half of the areas above medium and high levels. The overall spatial pattern shows reducing FVC from the Longmen Mountains to central plains region. The changing trend of FVC is increase first and then decrease with increasing elevation rendering. (2) The area of vegetation damage caused by the Wenchuan Earthquake is 6.91×10⁵ hm².FVC is mainly distributed at elevations of 324~800 m, where the FVC decreased with increasing elevation. The vegetation coverage is distributed in the area where the slope is lower than 20°.It is mainly distributed on the eastern, southern, gentle, western slopes, and hilly area. (3) After five years of natural regeneration, 4.88×10⁵ hm² of the destroyed areas were recovered. The recovered vegetation area occurred mainly across elevation ranges of 324~1 000 m, on slopes of<30°, and gentle, southern, eastern, and western aspects, hill regions, mountain area of high ups and downs. (4) Elevation, slope, and geomorphology have significantly larger effects than aspects of vegetation damage or restoration, and provide very useful information for decision-making and policy-planning in Chengdu plain and its surrounding area, after the Wenchuan Earthquake.