兰州市彩钢板建筑时空聚集特征及其对城市热岛效应影响分析

Spatio-temporal Agglomeration Characteristics of Color Steel Plate Buildings in Lanzhou and Their Influence on Urban Heat Island Effect

城市中大规模彩钢板建筑明显影响城市热环境,研究二者的相关关系对城市生态可持续发展具有重要价值。该文首先基于Google和GF-2影像利用典型编—解码U-net神经网络方法提取兰州市2008年、2017年彩钢板建筑空间分布,并采用距离加权方法计算彩钢板建筑的聚集密度;其次,基于Landsat卫星影像反演与Google和GF-2对应时间的地表温度,并计算彩钢板建筑的景观指数;最后,分析彩钢板建筑时空变化特征及其与城市热岛效应的相关关系。结果表明:2008-2017年兰州市主城区彩钢板建筑及其聚集程度总体呈增长趋势,彩钢板建筑聚集密度与地表温度呈显著线性正相关,彩钢板建筑斑块密度、斑块凝聚度指数、最大斑块指数及周长面积分维是影响地表温度的关键指标。

The large-scale color steel plate buildings in the city have brought obvious impact on the urban thermal environment,and the research on the correlation between the two has important value for the sustainable development of urban ecology.In this paper,firstly,based on Google and GF-2 images,the typical encoding-decoding U-net neural network method is used to extract the information of color steel plate buildings in Lanzhou in 2008 and 2017;secondly,the distance-weighted method is used to calculate and analyze the aggregation density of color steel plate buildings;thirdly,the land surface temperature corresponding to Google and GF-2 is calculated based on the inversion of Landsat satellite images and the landscape indexes of color steel plate buildings are calculated;finally,the temporal and spatial variation characteristics of the color steel plate buildings in the main urban area of Lanzhou and their correlation with the urban heat island effect are analyzed.The study results show that from 2008 to 2017,the color steel plate buildings in Lanzhou have an overall growth trend,and the agglomeration degree of color steel plate buildings is increasing.The aggregation density of color steel plate buildings has a significant linear positive correlation with the surface temperature.The patch density,patch cohesion index,fractal dimension of perimeter and area and the maximum patch index of color steel plate buildings are the key indicators that affect the surface temperature.