Dynamics of Land Surface Temperature in Response to Land Cover Changes in Lagos Metropolis

Abstract

Land Surface Temperature (LST) is one of the key environmental parameters affected by land cover change. Lagos State has been experiencing an increase in surface temperature due to growing areas of impervious surfaces caused by anthropogenic urban sprawl. While the change in LST has been established, its continuous monitoring and relationship with continuing Land Cover (LC) changes have become imperative for appropriate management and policy actions. This study investigated the effect of land cover change on LST in the rapidly urbanising Lagos metropolis. Using spatio-temporal Landsat imageries with their thermal bands and ancillary data, land cover and LST changes were assessed from 1984 - 2015. The spatial patterns of LST and LC were derived to examine the response of LST to urban growth. Findings confirmed urban sprawl in previously rural areas northward of the metropolis in LGAs such as Ikorodu, Kosofe and those fringing the state’s border with Ogun State. This also confirmed new growth areas as occurring west of the metropolis in Amuwo-Odofin LGA. The results further showed that the rapid urbanisation in Lagos metropolis has altered the surface thermal environment as indicated by increased LST. Built-up area and bare land accounted for the highest increase in LST (as high as 1.5℃ in some areas) while wetlands and other vegetated areas played a vital role in moderating the surface temperature in areas they still occupy. This provides reasonable evidence for the appropriate authorities to institute requisite policies and actions towards moderating urban sprawl while ramping up the development of urban green infrastructure to counter global warming.