Mr Bill Becker

Honours thesis

Quantifying the urban heat island effect on Adelaide's coastline

The growth in Adelaide’s urban population has been associated with environmental degradation, including a disturbance in the dynamic equilibrium that once existed in the Adelaide coastline. The problem is worsened by the coast’s proximity to the Adelaide CBD (10km) on the western side, and the Mount Lofty range bordering eastern Adelaide, forcing urban development to advance to the north and south along the coastline. Urbanization has resulted in the eradication of most natural vegetation in the Adelaide area, elevating temperatures above those found in a rural area with similar topographical characteristics. This is known as the Urban Heat Island (UHI) effect, and has been well documented in large cities, especially those in the northern hemisphere. This report investigates the trend in Adelaide’s air temperature since recording started in 1887. The presence of an UHI usually causes an increase in nocturnal temperature, which is evident in the Adelaide temperature data and reported accordingly. Synoptic conditions such as cloud cover and wind velocity were found to have some bearing on the intensity of the UHI effect at a given time. Specifically, a negative correlation between these two variables and UHI intensity is established. An attempt to explore the association between UHI intensity and traffic emissions is described. Many studies have focussed on investigating the link between UHI and wind velocity, discovering that the presence of an UHI induces stronger winds. An association between sea breeze strength and urban growth is established in this report, where an increasing trend in sea breeze strength is evident from 1955. This conclusion has significant repercussions on the beaches of coastal cities such as Adelaide, as intensifying sea breezes result in increased wave heights, and therefore increased coastal erosion. This issue highlights the need for mitigation schemes to prevent a further rise in UHI intensity, which in turn will not only prevent coastal erosion, but dampen the effect on public health during heat waves and contribute to the aversion of global warming. Opportunities for further investigation into the effect of the UHI in Adelaide are also presented.