基于RS的城市绿地及其固碳能力演变研究——以重庆市主城区为例

A Remote Sensing-Based Research about the Evolution of City Greenbelts and Their Carbon Sequestration Ability——A Case Study in Chongqing Main City Zone

利用重庆市LandsatTM数据,采用归一化植被指数(NDVI)、归一化建筑指数(NDBI),提取重庆主城区绿地、建设用地等地类信息,结合区位商理论和citygreen储碳模型计算了重庆主城各区2000,2003和2007年绿地率区位商、绿地年固碳量和固碳率.结果分析表明:2000年到2007年重庆主城区绿地面积、建筑用地面积、绿地年固碳量均有不同程度增长,年均增长率分别为3.7%,13.2%和7.6%;绿地大体呈现以渝中区为极低中心,周边组团城区为较高起伏边缘的盆状空间格局;绿地固碳能力基本与绿地格局一致,且固碳能力增幅大于绿地面积增幅.研究认为,城市建设等人类活动影响城市绿地的增减,而绿地面积和绿地结构组成是影响绿地固碳能力的主要因素.

LandsatTM image data and NDVI and NDBI were used to extract the information about the areas of city greenbelts,bare land and construction land.Using the location quotient theory and the citygeen model in combination,the location quotient of the greenbelts of Chongqing main city zone and its annual carbon sequestration amount and annual carbon sequestration rate in 2000,2003 and 2007 were calculated.The results showed that the areas of city greenbelts and construction land and their carbon sequestration ability increased to different extents from 2000 to 2007,with an average annual growth rate of 3.7%,13.2% and 7.6%,respectively.In spatial-temporal distribution,the city greenbelt exhibited a basin-shaped structure,with Yuzhong District at the bottom,surrounded by a zigzaging circle.The carbon sequestration ability of the greenbelts was correlated with their spatial-temporal pattern and the increase extent was greater than that of their acreage.It is concluded that human activities impact the growth of greenbelt area,and the changes in the acreage and composition of greenbelts are the main factors influencing their ability of carbon sequestration.