Rapid urbanization effect on local climate: Intercomparison of climate trends in Shenzhen and Hong Kong, 1968-2013

Abstract

An intercomparison of climate trends between 2 adjacent large cities, Shenzhen and Hong Kong, in the past 46 yr (1968-2013) suggests that the rate of urbanization is clearly reflected in the rate of the change in local climate. Since becoming a special economic zone in 1980, Shenzhen has experienced a very rapid urbanization process. In only 30 yr, Shenzhen has transformed from a small town into a metropolis rivaling Hong Kong. The gross domestic product and urban built-up area in Shenzhen have increased rapidly. Climate data analysis over the last 46 yr showed a greater rate of change in climate in Shenzhen than in Hong Kong over the same period. In Shenzhen, average annual temperature warmed by 1.63 ± 0.18°C (∼0.35 ± 0.04°C per decade), average maximum temperature increased by 0.90 ± 0.19°C, average minimum temperature increased by 2.09 ± 0.23°C and the diurnal temperature range (DTR) decreased by 1.18 ± 0.23°C. Over the same period in Hong Kong, average temperature increased by 0.47 ± 0.20°C (∼0.10 ± 0.04°C per decade), maximum temperature increased by 0.12 ± 0.28°C, minimum temperature increased by 0.55 ± 0.20°C and DTR decreased by 0.43 ± 0.27°C. In addition, relative humidity in Shenzhen decreased by 13.13 ± 1.78% in the last 46 yr, while there were no significant changes in Hong Kong. Finally, data analysis showed that urbanization has no significant effect on total rainfall for both cities.