Rapid urban growth causes significant decrease in green cover which ultimately results higher temperature and strongest Urban Thermal Field Variance Index (UTFVI) effect. Rajshahi has the highest heat index score after the southwest region. Hence, Rajshahi city is particularly vulnerable to heat waves. There is a major gap in exploring the micro-scale thermal conditions in Rajshahi. The primary purpose of this study is to evaluate urban ecological health in the four major urbanized zones of Rajshahi City Corporation (RCC) area namely, City Centre, Eastern Fringe, Western Fringe and Northern Fringe over the past three decades (1992–2022). Land Use/Land Cover (LULC) variations, ecological balance, and their effects on the thermal environment at various scales have all been extensively analyzed using an integrated approach of geographic information systems (GIS) and remote sensing (RS). Landsat satellite images with a 30 m spatial resolution were used to carry out this micro-scale study. In ENVI 5.3 software, the Support Vector Machines (SVM) algorithm was used for its accuracy and popularity in image classification. Images from the past three decades were classified at five-year intervals using SVM, relying on specific training procedures. Four land cover indices are utilized to assess the geographical and temporal differences in Land Surface Temperature (LST) caused by land cover. Statistical relationship between various land cover indices and LST was performed using Statistical Package/Program for Social Sciences (SPSS). The overall increase of urban area during the study period was 53.61 %, resulting in a concentration of 28.09 km2 of urban area (58.45 %) in 2022 from 2.32 km2 (4.83 %) of 1992. The directional analysis of Thermal Comfort Zone (TCZ) reveals a significant decrease of thermal comfort environment due to loss of green space in NE to NW region during the study period. The regression analysis among LULC and LST revealed significant negative relation (p < 0.05) for water body and vegetation cover while the relationship is positive for urban area which concluded that urban centres experienced the most substantial LST increases, as evidenced by the study's observation of a substantial increase in higher temperature zones. This urban encroachment, which is influenced by factors such as population growth and economic development, has resulted in a reduction in comfortable thermal zones, which has exacerbated the urban heat island effect and impacted the ecological sustainability of urban areas. By avoiding concentrated impermeable surfaces, such as built-up areas, and boosting green cover, urban development can effectively mitigate the effects of LST and UTFVI. Again, effective distribution of LULC can play a crucial role in mitigating the effects to a significant extent. The findings of this study reflect the necessity of proper sustainable solution through the successful implementation of urban planning techniques which would help urban planners and policymakers to create effective strategies in order to ensure comfortable thermal environment.

中文翻译：

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估算微尺度土地利用/土地覆盖变化对孟加拉国拉杰沙希市城市热舒适区的影响：一种基于 GIS 和遥感的方法


城市的快速增长导致绿色覆盖率显著减少，最终导致温度升高和最强的城市热场方差指数 （UTFVI） 效应。拉杰沙希的热指数得分最高，仅次于西南地区。因此，拉杰沙希市特别容易受到热浪的影响。在探索拉杰沙希岛的微观尺度热条件方面存在重大差距。本研究的主要目的是评估过去三十年（1992-2022 年）拉杰沙希市公司 （RCC） 地区四个主要城市化区的城市生态健康状况，即市中心、东部边缘、西部边缘和北部边缘。土地利用/土地覆盖 （LULC） 变化、生态平衡及其在各种尺度上对热环境的影响都使用地理信息系统 （GIS） 和遥感 （RS） 的综合方法进行了广泛的分析。使用空间分辨率为 30 m 的 Landsat 卫星图像进行这项微尺度研究。在 ENVI 5.3 软件中，支持向量机 （SVM） 算法因其在图像分类中的准确性和普及性而被使用。过去三十年的图像使用 SVM 每隔五年对图像进行分类，具体取决于特定的训练程序。使用四个土地覆盖指数来评估由土地覆盖引起的地表温度 （LST） 的地理和时间差异。使用社会科学统计包/程序 （SPSS） 进行各种土地覆盖指数与 LST 之间的统计关系。研究期间城镇面积总体增长 53.61%，导致 2022 年城镇面积集中度从 1992 年的 2.32 km2 （4.83%） 增加到 28.09 km2 （58.45 %）。 热舒适区 （TCZ） 的方向分析显示，在研究期间，由于东北至西北地区绿地的损失，热舒适环境显着减少。LULC 和 LST 之间的回归分析显示，水体和植被覆盖度呈显著负相关 （p < 0.05），而城市地区呈正相关，得出的结论是城市中心经历了最显着的 LST 增加，研究观察到高温区的显着增加证明了这一点。这种受人口增长和经济发展等因素影响的城市侵占导致舒适的热区减少，这加剧了城市热岛效应并影响了城市地区的生态可持续性。通过避开集中的不透水表面（如建筑区）并提高绿色覆盖率，城市发展可以有效减轻 LST 和 UTFVI 的影响。同样，LULC 的有效分布可以在很大程度上减轻影响方面发挥关键作用。本研究的结果反映了通过成功实施城市规划技术来制定适当可持续解决方案的必要性，这将帮助城市规划者和政策制定者制定有效的策略，以确保舒适的热环境。