Trend Assessment of Land Surface Temperature Over Different Land Use/Land Cover in Greater Karu Urban Area of Nigeria

This study assessed trend of Land Surface Temperature over different land use/land cover in Greater Karu Urban Area of Nigeriausing multi-criteria research design. The remotely sensed imageries from Landsat TM, Landsat ETM and Landsat OLI that LANDSAT TM were obtained for 4 different epochs (1992, 2002, 2012 and 2022). The study used ESRI ArcGIS 10.8, ArcGIS Pro version 3.1.3 and Qgis version 3.22.5 for data acquisition, processing, modelling and analysis. Findings shows that during the dry season area with low LST (< 200C) and area with moderate LST (>20–23) declining trend with y = -46.29x + 196.25 and y = -44.18x + 340.7 respectively. Area with high LST (>23-260C) and area with extreme LST (>260C) had increasing trend with y = 21.75x + 192.7 and y = 68.72x - 6.75 respectively. During the wet season, area with low LST (< 200C) and area with moderate LST (>20–23) also depict declining trend with y = -7.83x + 35.8 and y = -9.91x + 59.9 respectively. Area with high LST (>23-260C) and area with extreme LST (>260C) had an increasing trend with y = 4.94x + 16.95 and y = 12.82x - 12.7 respectively. The findings shows that area having low LST (≤200C) and area with moderate LST (>200C-230C) have been decreasing within the study period of 1992 t0 2022 meaning a decadal decrease during the dry and wet season while area with high LST (>230C-260C) and area with extreme LST (>260C) had an increasing trend with equation depicting strong positive correlation between advancing years and increase in area with extreme LST values. The LST for newly developed LULC from 1992-2022 shows a positive increase for both dry season and wet season in GKUA but with the mean LST value higher in dry season and lower in wet season. The conversion of vegetal cover and cropland into bare surfaces and built-up area in quest for various urban infrastructures in GKUA for residency, transportation, industry, and other purposes causes major land use change that substantially affects LST, and this will surelyaffect the urban environment and ecosystem thereby decreases human thermal comfort for the urban dwellers.This study recommends urban greening of GKUA of Nasarawa State.

Keywords: Gkua, LST, Discomfort, Index, Trend, Change, Detection.