Assessing the impact of Land Use Land Cover changes on land surface temperature over Kigali, Rwanda in the past three decades

Abstract

Land use changes and urban activities cause environmental degradation and climate change. This study aims to assess the impacts of Land Use Land Cover (LULC) changes on land surface temperature (LST) in Kigali, Rwanda over the past three decades. The combined techniques of remote sensing and GIS were applied to generate good quality Landsat images, categorize land use classes and retrieve urban indices. The modified Mann-Kendall test and Sen’s slope estimator were used to analyze trends in LST. The results indicate that between 1990 and 2020, the extent of builtup and forest areas have increased at an average rate of 3.39 km2/year and 2.42 km2/year respectively, while open land has decreased at an average rate of 5.81 km2/year. In the same period, water bodies and wetlands showed minimal changes with an increase of 1.56 km2 and a decrease of 1.66 km2 for water bodies and wetlands respectively. The slope magnitudes of LST are predominantly positive (p ≤ 0.05) with a high increase observed in dry seasons (0.51 °C per decade for Tmin in JJA and 0.49 °C per decade for Tmax in JF). The positive correlations between LST and urban indices were observed in all studied subregions (all values are above 0.61, p ≤ 0.05). The findings of this study are useful for the development of future urban land use schemes and the adoption of mitigation and adaptation strategies in response to climate change.