Urban land expansion plays an important role in climate change. It is significant to select a reasonable urban expansion pattern to mitigate the impact of urban land expansion on the regional climate in the rapid urbanization process. In this paper, taking Wuhan metropolitan as the case study area, and three urbanization patterns scenarios are designed to simulate spatial patterns of urban land expansion in the future using the Partitioned and Asynchronous Cellular Automata Model. Then, simulation results of land use are adjusted and inputted into WRF (Weather Research and Forecast) model to simulate regional climate change. The results show that: (1) warming effect is strongest under centralized urbanization while it is on the opposite under decentralized scenario; (2) the warming effect is stronger and wider in centralized urbanization scenario than in decentralized urbanization scenario; (3) the impact trends of urban land use expansion on precipitation are basically the same under different scenarios; (4) and spatial distribution of rainfall was more concentrated under centralized urbanization scenario, and there is a rainfall center of wider scope, greater intensity. Accordingly, it can be concluded that decentralized urbanization is a reasonable urbanization pattern to mitigate climate change in rapid urbanization period. 1. Introduction Urbanization is one of the most important anthropogenic influences on climate. By transforming the nature land cover to the artificial state, and anthropogenic heat emissions, the process of urbanization has a profound impact on global climate change [1]. Therefore, with the rapid urbanization, the impact of urbanization especially urban land expansion on global climate change has been one of the hotspots in research fields [2–5]. Using 40 years’ climate change data and land use data of Hong Kong, Ka and Edward (2013) found that with the evolution of natural vegetation and rural landscape to urban landscape, the trend of rising temperatures in urban areas has become more apparent [6]. Combined with remote sensing and spatial statistical model, Xiong et al. (2012) studied the impact of four periods of urban land expansion on surface temperature from 1990 to 2009 in Guangzhou, and found that there is a significant correlation between the urban heat island intensity and urban land expansion in Guangzhou City [7]. Guo et al. (2012) constructed urbanization index according to different land covers and analyzed effects of different degrees of urbanizations on surface temperature [8]. The results indicated that
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