Precipitation characteristics in the Three Gorges Dam vicinity

After the building of the Three Gorges Dam (TGD), the water level abruptly rose from 66 to 135 m in June 2003, and the land use characteristics changed significantly throughout the TGD region. More and more people are concerned with the effect of the TGD reservoir on climate. In this paper, the decadal variation of precipitation in the vicinity of the TGD was analysed using daily data from 27 rain gauges from 1960 to 2005. The empirical orthogonal function (EOF) analysis of annual precipitation anomalies indicates a clear difference in spatial distribution, with an opposite signal for the change in precipitation in the northern and southern areas of the Yangtze River, i. e. precipitation increases in the northern area are accompanied with decreases in the southern area and vice versa. The similar dipole pattern of precipitation variation around the TGD also occurred before the TGD, for example, in the period from 1977 to 1984. Therefore, it has not been shown with reasonable significance that the similar dipole pattern of precipitation variation around the TGD has been affected by the TGD. Copyright (C) 2009 Royal Meteorological Society