1984—2014年北京地区不透水地表的时空变化及其温度效应研究

Spatial-temporal change features of impervious surface and its effect on land surface temperature from 1984 to 2014 in Beijing

研究城市地表覆盖与地表温度(LST)的关系对改善城市生态环境具有重要科学意义。在Landsat TM数据支持下,利用线性光谱混合分析模型提取不透水地表信息,结合LST和地表热通量,分析不透水地表覆盖度(ISA)和LST的时空变化特征及其相互关系,探讨不透水地表对LST的影响机理。结果表明:1984—2014年北京不透水地表面积迅速增长,中覆盖度比例下降,高覆盖度比例增加;LST从市中心向郊区递减,高温区向外扩张;LST和ISA呈显著正相关,但不是简单的线性关系;ISA处于0.6~0.9时LST上升速率最快,减少ISA在此范围内的不透水地表集中分布可缓解高温区集中的现象。

It is of great scientific significance to study the relationship between urban surface cover and land surface temperature(LST)for improving urban ecological environment.Based on the Landsat TM data,this paper uses the linear spectral hybrid analysis model to extract the impervious surface land information.Combined with the LST and surface heat flux,the spatial-temporal variation characteristics and inter relationships of the impervious surface area(ISA)and the LST are analyzed.The results show that the ISA of Beijing increased rapidly from 1984 to 2014.The medium coverage of ISA decreased,while high coverage increased remarkably.The LST decreased from the city center to the suburbs,and the high temperature area was expanding continuously.There was a significant positive correlation between the LST and ISA,and the rate of the LST rise was the fastest when ISA was at 0.6-0.9.So reducing ISA can alleviate the phenomenon of high temperature area concentration.