Climate Change and Its Attribution in Three Gorges Reservoir Area, China

Climate change in dam areas is one of the environmental problems associated with dams. However, the main factors and mechanisms that impact climate change in dam areas remain unclear. In this study, linear regression, the observed minus reanalyzed (OMR) method, and multi-source data are used to assess climate change in the Three Gorges Reservoir Area of China and investigate the main impact factors among the controversial factors (land cover change, environmental climate, and reservoir impoundment). Our results indicate that turning points of trend changes for annual fog days (FD), annual average temperature (T), and annual average relative humidity (RH) occurred at around 1996 during the period 1973-2013, and annual precipitation (PRE) suggested no obvious turning point. The change trends after 1996 were steeper than before 1996. These changes are mainly closely correlated with environmental climate. In particular, temperature was significantly correlated with environmental temperature (1979-2013: r = 0.799, p < 0.01), and their relationship was stronger after 1990 (r = 0.842, p < 0.01). Moreover, the turning point for FD, T, and RH also correlated with land use/cover change. In addition, reservoir impoundment showed an obvious humidification effect (OMR RH correlated with water area: r = 0.566, p < 0.01). Our findings support the view that climate change in dam areas is mainly affected by environmental climate changes.