Forecasting Summer Rainfall and Streamflow over the Yangtze River Valley Using Western Pacific Subtropical High Feature

The western Pacific subtropical high (WPSH) is one of the key systems affecting summer rainfall over Yangtze River Valley in China. In this study, forecasting capacity WPSH for and streamflow evaluated based on index (WPSHI) derived from NCEP/NCAR reanalysis dataset. It has been found that WPSHI can identify extreme flood years with a higher skill than normal wet years. Specifically, exceedance probability skills thresholds rainfall. For streamflow, adding as predictor only enhances relative to models antecedent streamflow. Under same framework, performances two postprocessing approaches dynamical forecasts, i.e., model output statistics (MOS) approach reanalysis-based (RAN) are compared. Hindcasts Climate Forecast System version 2 National Center Environmental Prediction (CFSv2) used calculate WPSHI, which result shows RAN performs better MOS approach. This study emphasizes fact would largely depend selected threshold predictand, should be noticed future studies long-term field.