加尔各答市地表温度与不透水面比例季相相关性研究

城市化的显著特征是自然地表不断被热容量大的不透水面取代，进而造成城市热岛效应和严重的城市生态问题。孟中印缅经济走廊是古代南方丝绸之路的重要路段和“一带一路”建设的重要战略通道，加尔各答市是孟中印缅经济走廊印度境内的重要节点城市，战略地位重要，对其城市化进程及与地表温度相关性研究对孟中印缅经济走廊印度段建设具有重要的借鉴意义。传统地表温度与不透水面的相关性研究主要以年为时间尺度，较少关注城市不同季相地表温度与不透水面的相关性及其差异。以热带季风气候的季相区分为依据，基于旱季、雨季和凉季3个季相的Landsat 8影像反演了加尔各答市地表温度和不透水面比例，定量研究两者的关系，探讨了地表温度与不透水面比例的季相相关性。结果表明：①研究区内，低温和高温空间分布相对比较集中，高温区域集中在建成区，而低温主要分布在茂密植被覆盖区和水体区域；②加尔各答市从旱季到雨季再到凉季热岛效应程度总体呈下降趋势，旱季时城市热岛效应最强，凉季时城市热岛效应最弱；③每个季相，地表温度与不透水面比例都呈正相关，地表温度随着不透水面比例增加均呈现先快速上升，后缓慢增加，最后急剧增加的趋势，其中旱季时地表温度增长最快，雨季时地表温度增长次之，凉季时地表温度增长最慢。加尔各答市热环境研究将对孟中印缅经济走廊印度段城市热环境背景及生态效应认知等方面产生积极意义。

Seasonal Variations in the Relationship between Land Surface Temperature and Impervious Surface Percentage in Kolkata

The remarkable feature of urbanization is that the natural surface is constantly replaced by the impervious surface with large heat capacity， which leads to the Urban Heat Island （UHI） and other serious urban ecological problems. The Bangladesh-China-India-Myanmar （BCIM） Economic Corridor is an important road section of the ancient Southern Silk Road and a strategic passage for the construction of the “Belt and Road” Initiative （BRI）. Kolkata， located at the strategic position of the BCIM Economic Corridor， is extremely important for the BCIM project. So it is of great significance to research the development of Kolkata and its correlation to Land Surface Temperature （LST） for the construction of the Indian section in the BCIM Economic Corridor. Traditional researches on the relationship between LST and Impervious Surface Percentage （ISP） are mainly based on years， however， few researchers have paid attention to seasonal variations. Based on Landsat images of dry season， rainy season and cool season， this paper retrieved LST and ISP in order to explore and analyze the seasonal variation in the relationship between LST and the ISP. The results indicated that： ① For this study， the distribution of low temperature and high temperature was concentrated， and the high temperature was concentrated in the built-up area， but the low temperature distributed mainly over water body and the area with relatively high vegetation cover； ② The overall UHI effect had been decreasing from dry season to rainy season and then to cool season， and that was strongest in dry season and weakest in cold season； ③ In each season， the LST was positively correlated with ISP. With the increase of the ISP， the LST increased rapidly at first， then slowly， and finally sharply. And when the ISP increased by 0.1， the LST increased by 0.53 ℃ in dry season， 0.35 ℃ in rainy season and 0.26 ℃ in cool season. In summary， the study of thermal environment in Kolkata will be of positive significance to cognition of thermal environment background and ecological effects in India section of BCIM Economic Corridor.