The Spatio-temporal Dynamics Of Urban Heat Island During Urbanization Processes In Shanghai Metropolitan Regions

In this thesis, historical monthly air temperature from 1960 to 2009 from 11 weather stations in Shanghai metropolitan regions, air temperature data of 2007 from 44 weather stations,1989-2005 land use data, and urban historical population were utilized to study the impacts of climatic change and urbanization on urban heat island (UHI), and spatiotemporal dynamics of UHI in Shanghai. My main findings were shown as following:1. There are marked warming trends of air temperature in Shanghai in the past 50 years. The increasing rate of mean, maxium and minimum air temperature are 0.379℃/10a,0.332℃/10a and 0.427℃/10a, respectively. There are distinctive cold and warm periods of the air temperature in Shanghai, the cold period which indicative of negative temperature difference from the average, occurred in the time of 1960-1980s, the warm which indicative of positive temperature difference from the average, occurred in the time of 1990-2009. The switch time between the cold and the warm occurred in the early 1990s which is consisted with the initial time of rapid urbanization in Shanghai.2. In the past 50 years, there are distinctive cold-warm pattern for the seasonal change of air temperature which is similar with that of the interannual. But the initial time of warmer winter was advanced comparing to the other seansons.3. The global warming and urbanization both contribute to warming in Shanghai in the past 50 years, but the former contributes more than the later. The contribution from urbanization mainly to minimum air temperature and occurred in the time of 1990s.4. The UHI intensity exhibited an increasing trends at the speed of 0.29℃/10a in the past 50 years. While the UHI intensity between central urban and suburban areas decreased with urbanization.5. There are marked spatiotemporal dynamics at seasonal and diurnal time scale for UHI in Shanghai. The stronger UHI intensity occurred in autumn and winter, the weakest UHI occurred in summer. The highest UHI intensity happened in the evening time of 20:00pm to 05:00am. The UHI intensity in daytime was far lower than that in nighttime. There were multiple UHIs mainly existed in suburban areas in the time of 14:00pm and have the largest area, but in the other time, the UHI concentrated in central urban areas and has smaller area compared to the daytime.6. There are significant positive linear relationship between UHI intensity and urban population size. The UHI intensity increases 0.32℃with every million population increase. The strong correlation between UHI intensity and urban landscape pattern demonstrated the impact of urban landscape pattern on UHI.