Spatio-Temporal Variability of Simulated 2 m Air Temperature for Nairobi City, Kenya

Nairobi city in Kenya is an example of the many cities in Africa\r\nexperiencing rapid growth and too many environmental impacts, including the\r\nurban heat islands (UHI) phenomenon. UHI develops and escalates under\r\noutrageous hot periods, such as during heatwave, which can affect outdoor\r\nmicroclimate, human thermal comfort, and health and also increase the energy\r\ndemand for cooling. This study used the MUKLIMO_3 model to reveal the spatial\r\nheterogeneity and temporal variability of 2 m\r\nair temperature fields and thermally sensitive areas within Nairobi\r\ncity. The model reproduced the potential summer day conditions through\r\nidealized simulations of temperature, wind, and relative humidity based on the\r\nurban topography and local climate zones (LCZs) data at a spatial resolution of\r\n200 m. The aim was to expand knowledge of urban climate change based on the\r\naccompanying extensive modification of land use and land cover that are\r\ncritical for the local-scale atmospheric circulation. The model results\r\nrevealed intricate spatiotemporal patterns of 2 m air temperature fields, which\r\naccrued from terrain-induced flows and land surface heterogeneity as described\r\nby the LCZ parameters. The variation in canopy layer UHI was a joined impact of\r\nthe unfavorable location of the town and urbanization process, which added to\r\nthe formation of excessive urban heat load. The study concluded that the\r\nenhancement of urban heat load in Nairobi city could be linked to the concept\r\nof rapid urbanization process and its\r\nhistorical development. Therefore urban planning strategies such as\r\noptimization of mixed building heights and the introduction of green \u0026 blue\r\ninfrastructure were critical to mitigating heat-stress across Nairobi city.