一带一路沿海超大城市热岛时空特征遥感分析

城市热岛不仅影响城市局地及区域气候，而且对城市空气质量、能源消耗、居民健康等有显著的负面作用。利用长时序遥感数据，系统地分析各超大城市热岛的时空特征，能够为城市热岛效应减缓政策的制定提供参考，对带路城市可持续发展具有重要意义。基于2001~2017年MODIS地表温度产品和Landsat土地利用分类数据，以城市热岛强度（Surface Urban Heat Island Intensity， SUHII）作为指标，从季节和年际的角度分析一带一路沿海超大城市2001~2017年热岛效应时空格局的变化。研究结果表明：①2001~2017年期间各超大城市的核心区存在扩张趋势，高强度热岛主要分布在人口活动密集的城市核心区；②年均城市热岛强度最大的城市是卡拉奇，多年SUHII平均值为3.02 ℃，热岛强度显著上升的是金奈（0.07 ℃/a，P<0.1）；③各城市热岛强度存在季节性差异，其中夏季城市热岛强度最大的城市是伊斯坦布尔，SUHII平均值为2.88 ℃，冬季城市热岛强度最大的城市是卡拉奇，SUHII平均值为4.45 ℃。

Spatio-temporal Dynamics of Surface Urban Heat Island in Coastal Mega Cities along the Belt and Road from Remote Sensing Data

Urban heat island not only affects local and regional climate of the city， but also has significant adverse effects on urban air quality， energy consumption and human health. By using long time series of remote sensing data， the systematic analysis of the temporal and spatial characteristics of the heat island in megacities can provide helpful information for the formulation of policies for urban heat island effect mitigation， and thus is of great importance for the urban sustainable development in the Belt and Road region. Based on the MODIS land surface temperature products from 2001 to 2017 and land use classification data from Landsat， the spatiotemporal changes of the surface urban heat island effect were analyzed from the seasonal and inter-annual perspectives in the coastal mega cities by using the Surface Urban Heat Island Intensity （SUHII） as an indicator. The analysis results showed that during 2001~2017， the urban areas of mega cities all experienced an expanding process， and the high intensity urban heat island was mainly distributed in the densely populated core areas of the cities. Secondly， among the 10 megacities， the annual average SUHII of Karachi was strongest with the value of 3.02 ℃， and the SUHII of Chennai showed a significant upward trend （0.07 ℃/a， P<0.1）. Finally， there were seasonal differences in the urban heat island among the mega cities. In summer， the average SUHII of Istanbul was strongest with the value of 2.88 ℃. In winter， the average SUHII of Karachi was the strongest with the value of 4.45 ℃.