广州市中心城区城市不透水地表覆盖结构与地表温度的关联性研究

The relationship between the impervious surface covering structure and land surface temperature in Guangzhou downtown

城市不透水地表作为城市地表的重要组成,正确认识城市不透水地表覆盖结构对城市热岛的影响,可为改善城市热环境提供策略。文章基于Landsat-8 OLI/TIRS和GF-2遥感影像,通过反演地表温度和提取城市不透水地表覆盖信息,利用GIS空间分析技术、景观格局指数和统计分析方法,分析了广州中心城区城市不透水地表覆盖结构对城市地表温度的影响特征。主要结果如下:(1)广州中心城区地表温度分布空间异质特征明显,其地温图呈现斑块镶嵌状,且有明显的高温、低温区域存在,其中不透水地表覆盖平均温度最高,裸地次之,最低是水域和绿地。(2)多数空间尺度分析结果显示,随空间分析尺度从630 m×630 m增至1800 m×1800 m,不透水地表比例和地表温度均存在正相关关系,其相关系数(程度)在0.61—0.68(P<0.01)之间。(3)地表温度和不透水地表斑块的最大斑块指数、平均斑块面积指数、平均形状指数和聚集度指数显著正相关(P<0.01),其中不透水地表的聚集度对地表温度的影响最大,但基于网格单元分析的景观指数曲线与平均地表温度之间未呈现完全一一对应关系。城市不透水地表显著影响地表温度,合理调整设计城市不透水空间分布格局,可有效减弱城市热岛强度。

Urban impervious surface is an important component of urban surface,and a correct understanding of the influence of urban impervious surface cover structure on urban heat island can provide strategies for improving urban thermal environment.Based on Landsat-8 OLI/TIRS and GF-2 remote sensing images,this paper analyzes the influence characteristics of impervious urban surface cover structure on urban surface temperature in Guangzhou downtown by inverting surface temperature and extracting impervious urban surface cover information,using GIS spatial analysis technology,landscape pattern index and statistical analysis method.The result are as follow.(1)The surface temperature distribution in Guangzhou downtown is characterized by obvious spatial heterogeneity.The geothermal map is inlaid with patches,and there are obvious high temperature and low temperature areas,among which the average temperature of impervious surface cover is the highest,followed by bare land,and the lowest is water area and green land.(2)Most spatial scale analysis results show that with the increase of spatial analysis scale from 630 m×630 m to 1800 m×1800 m,there is a positive correlation between impervious surface proportion and surface temperature,and the correlation coefficient and degree is 0.61-0.68(P<0.01)due to the difference of spatial analysis scale.(3)The maximum patch index,average patch area index,average shape index and aggregation index of impervious surface patches are significantly and positively correlated(P<0.01),where the aggregation degree of impervious surface has the greatest influence on surface temperature,but the landscape index curve based on grid cell analysis does not show a complete one-to-one correspondence with the average surface temperature.Urban impervious surface significantly affects surface temperature,and reasonable adjustment of urban impervious spatial distribution pattern can effectively reduce urban heat island intensity.