Climate teleconnections to Yangtze river seasonal streamflow at the Three Gorges Dam, China

In this study, we identify climatic influences on summer monsoon inflow to the Three Gorges Dam (TGD) in the Yangtze River Basin and use indices of these influences to predict streamflow one season ahead. Summer monsoon streamflow at Yichang hydrological station (YHS) was analyzed for the period 1882-2003. Statistical analysis was used to develop a predictive model for summer streamflow using preceding climate variables. Linear correlation maps were constructed using 3-month ahead climate fields to identify regions that exhibit teleconnections with streamflow at Yichang. The analysis revealed regions in the eastern Indian and western Pacific Oceans that influence YHS streamflow. These regions and variables are consistent with those identified by previous studies of regional rainfall. In addition, snow cover in the Yangtze upland region provides predictive skill, likely due to snowmelt contributions to streamflow. A regression model for prediction using these indices provides a prediction R-2 greater than 0.5, which is robust under the 'leave one out' cross-validation. A skillful prediction can provide guidance for water management in the Yangtze River Basin, e.g. the Three Gorges Dam and future projects for South-to-North water transfer. Copyright (c) 2006 Royal Meteorological Society