Spatiotemporal Effects of Land Use and River Morphological Change on the Microclimate of Rajshahi Metropolitan Area

Abstract

Microclimate is a climatic phenomenon of a very local area that is affected by the variation of natural earth surfaces in urban area. The urban growth expedites to change land use and land cover pattern of a city that modify the built environment, alter the composition of the atmosphere and form a distinct local climate in the cities. The radical land use and land cover change also alters the meteorological condition of a city. The relationship between land use land cover and thermal environment has long been studied to identify the impacts of urban growth but for this study area no such effort is taken. This study focuses on detecting the changing pattern of the cities adjacent Padma River and land uses, finally the impacts of such changes on the microclimate are assessed. This study is conducted based on Landsat time series data of 1989, 1996, 2005 and 2015 using ENVI and ArcGIS 10.2 softwares. The result demonstrates that the city is experiencing continuous change in land cover pattern, where the city centre is more vulnerable to change than its fringe. Another significant change is observed in the morphology of river Padma; it shows continuous shift of the river channel and increase in the Char land. The interactions of land use land cover and LST depicts a continuous increase in the mean surface temperature over bare soil following impervious area. The results underscore that two factors are contributing to influence the microclimate of the study area: First, the areal extent of surface water particularly the river Padma is losing stream and generating more bare soil (Char Land); second, impervious area is increasing and natural earth surfaces are decreasing.