Urbanization Effects on Local Climate Change in South China

According to the population data of South China, the meteorological stations in this region were divided into three categories: Big city stations, city stations, and suburban stations. Then, using the observational data collected at these stations during the period 1960-2011, we calculated the annual and seasonal average data, and obtained time series of anomaly data for temperature, high temperature days, precipitation, relative humidity, wind speed, and sunshine duration. The results showed the average temperatures of the big cities to have increasing trends in comparison with the background field. Furthermore, the frequency of annual high temperature days became higher, while the range of average temperature revealed a downward trend, especially in big cities. Precipitation amounts throughout the whole area declined, particularly with respect to light rain. Relative humidity, wind speed, and sunshine duration revealed a decreasing trend; moreover, under the influence of urbanization, the relative humidity, wind speed, and sunshine duration of big cities decreased significantly. South China lies in the largest urban agglomeration of China, while also being situated in the tropical monsoon area, where a complex climate system exists. Therefore, it is necessary to study the influence of urbanization in this area from the perspective of multiple variables.