Abstract: Using MODIS dataset during 2001-2012, impacts of water body at daytime and nighttime on land surface temperatures due to the Three Gorges Project were analyzed both in winter and summer. To fully consider the impacts of topography, it is found that high land surface temperature mainly located in the eastern part of Sichuan basin at daytime, and in the Yangtze River at nighttime. Diurnal temperature ranges in the Yangtze River and high altitude area are small, also diurnal temperature ranges in the water body in summer are less than those in winter. After removing impacts of climate background by subtracting the average land surface temperatures over the buffer zone XI from the water body and buffer zones I-X, temporal trends in winter daytime climb up in water body and buffer zones I-VI, land surface temperatures at winter night in the same range also have significant rise. Removing the impacts of climate background and then separating the topographical effects through subtracting the variables after impounding (2003-2012) from ones before impounding (2001-2002), it is shown that, relative to the period before impounding, winter land surface temperatures after impounding obviously increase, and the intensity and range at nighttime are stronger than at daytime. Summer land surface temperatures decrease, the intensity at nighttime is weaker than at daytime, respectively, and the corresponding diurnal temperature ranges in both winter and summer decrease. With increment in distance from the water body, additionally, the climatic effects of reservoir become weaker. The potential spatial zones of influences induced by the Three Gorges Project are limited to the distances of 0-8 km from the water body.

Key words: land surface temperature, MODIS dataset, Three Gorges Project, reservoir region