城市地表温度与关键景观要素的关系

Relationships between land surface temperature and key landscape elements in urban area

利用Landsat ETM+遥感影像,提取上海市外环线范围内的地表温度、不透水面率、归一化差值植被指数、改进的归一化差异水体指数,定量研究地表温度与城市关键景观类型之间的关系。结果表明:地表温度与不透水面率呈显著的线性正相关(R2=0.837);地表温度与归一化差值植被指数和改进的归一化差异水体指数呈非线性关系,但地表温度与正的归一化差值植被指数和正的改进的归一化差值水体指数呈显著线性关系。鉴于归一化差值植被指数和改进的归一化差异水体指数大于0时才能真正代表植被和水体,因此,建议今后研究地表温度时使用正的归一化差值植被指数和改进的归一化差异水体指数;地表温度与不透水面率、归一化差值植被指数和改进的归一化差值水体指数的多元线性回归分析表明,不透水面起着增温作用,植被、水体起降温作用,植被较水体的降温作用大。

By using Landsat ETM＋ image to derive the land surface temperature（LST）,percent impervious surface area（ISA）,normalized difference vegetation index（NDVI）,and modified normalized difference water index（MNDWI） within the outer ring of Shanghai,this paper quantitatively analyzed the relationships between the LST and the key landscape elements in Shanghai urban area.There was a significant positive linear relationship between the LST and ISA（R2=0.837）.The LST had nonlinear relationships with NDVI and MNDWI,but significant linear relationships with positive NDVI and positive MNDWI.Due to the fact that only positive NDVI and MNDWI can actually represent vegetation and water body,respectively,the two indices were recommended to be used in the future study of LST.The multiple linear regression analysis of the LST and the ISA,NDVI,and MNDWI showed that impervious surface area played the role of enhancing LST,vegetation and water body played the role of cooling LST,and vegetation played better role in cooling LST than water body did.