Urban heat island (UHI) is a phenomenon which may have adverse effects on our environment and is stimulated as a result of urbanization or land cover changes. Thermal remote sensing has been found beneficial to study the effect of urbanization on UHI intensity. This paper analyses the variation in land surface temperature (LST) with land cover changes in Varanasi city of India from 1989 to 2018 using Landsat satellite images. A new index named Urban Heat Intensity Ratio Index (UHIRI) was proposed to quantify the urban heat intensity from 1989 to 2018 which was found to increase from 0.36 in year 1989 to 0.87 in year 2018. Further, contribution of each land cover towards UHI was determined using land cover contribution index (LCCI). The negative value of LCCI for water and vegetation indicates its negative contribution towards UHI, whereas positive value of LCCI for bare soil and built-ups depicted its positive contribution towards UHI. The LCCI value for urban land cover shows significant increase in 29 years, i.e. 0.49, 1.43, 3.40 and 4.37 for years 1989, 1997, 2008 and 2018, respectively. The changes in normalized LST from years 1989 to 2018 for the conversion of bare land to built-ups and vegetation to built-ups were found to be as −0.11 and 0.42, respectively. This led to conclusion that the replacement of vegetation with urban land cover has severe impact on increasing UHI intensity.

城市热岛（UHI）是一种可能对环境造成不利影响的现象，由于城市化或土地覆被变化而受到刺激。已经发现热遥感对研究城市化对UHI强度的影响是有益的。本文利用Landsat卫星图像分析了1989年至2018年印度瓦拉纳西市地表温度（LST）随土地覆盖变化的变化。提出了一个新的指数，称为城市热强度比指数（UHIRI），以量化1989年至2018年的城市热强度，该指数从1989年的0.36增加到2018年的0.87。使用土地覆盖贡献指数（LCCI）确定。LCCI对水和植被的负值表明其对UHI的负贡献，LCCI对裸土和堆积物的正面价值说明了其对UHI的积极贡献。城市土地覆盖的LCCI值在29年中显示出显着增长，即1989年，1997年，2008年和2018年分别为0.49、1.43、3.40和4.37。发现从1989年到2018年的标准化LST的变化分别是-0.11和0.42，这是将裸地转换为集结地和将植被转换为集结地的情况。得出的结论是，用城市土地覆盖代替植被对增加UHI强度有严重影响。发现从1989年到2018年的标准化LST的变化分别是-0.11和0.42，这是将裸地转换为集结地和将植被转换为集结地的情况。得出的结论是，用城市土地覆盖代替植被对增加UHI强度有严重影响。发现从1989年到2018年的标准化LST的变化分别是-0.11和0.42，这是将裸地转换为集结地和将植被转换为集结地的情况。得出的结论是，用城市土地覆盖代替植被对增加UHI强度有严重影响。