TITLE:
Spatio-Temporal Variability of Simulated 2 m Air Temperature for Nairobi City, Kenya
AUTHORS:
Emmanuel Ochola Matsaba, Ines Langer, Aggrey Ochieng Adimo, John Bosco Mukundi, John Mwibanda Wesonga
KEYWORDS:
2 m Air Temperature, MUKLIMO_3 Model, Canopy Layer Urban Heat Is-land, Land Use Table, Urban Topography, Urban Parameters
JOURNAL NAME:
Current Urban Studies,
Vol.8 No.2,
May
6,
2020
ABSTRACT: Nairobi city in Kenya is an example of the many cities in Africa
experiencing rapid growth and too many environmental impacts, including the
urban heat islands (UHI) phenomenon. UHI develops and escalates under
outrageous hot periods, such as during heatwave, which can affect outdoor
microclimate, human thermal comfort, and health and also increase the energy
demand for cooling. This study used the MUKLIMO_3 model to reveal the spatial
heterogeneity and temporal variability of 2 m
air temperature fields and thermally sensitive areas within Nairobi
city. The model reproduced the potential summer day conditions through
idealized simulations of temperature, wind, and relative humidity based on the
urban topography and local climate zones (LCZs) data at a spatial resolution of
200 m. The aim was to expand knowledge of urban climate change based on the
accompanying extensive modification of land use and land cover that are
critical for the local-scale atmospheric circulation. The model results
revealed intricate spatiotemporal patterns of 2 m air temperature fields, which
accrued from terrain-induced flows and land surface heterogeneity as described
by the LCZ parameters. The variation in canopy layer UHI was a joined impact of
the unfavorable location of the town and urbanization process, which added to
the formation of excessive urban heat load. The study concluded that the
enhancement of urban heat load in Nairobi city could be linked to the concept
of rapid urbanization process and its
historical development. Therefore urban planning strategies such as
optimization of mixed building heights and the introduction of green & blue
infrastructure were critical to mitigating heat-stress across Nairobi city.