Southern Hemisphere's 700mb Geopotential Height Teleconnections and Their Potential for Seasonal Streamflow and Precipitation Forecasting Models in Australia and South America.

The principal modes of variation of 700mb Geopotential Heights (Z700 teleconnections) from the NCEP/NCAR reanalysis are related to seasonal precipitation and streamflow in Australia and South America. The precipitation and streamflow data were clustered into climatic regions. Seasonal precipitation and streamflow from each region were correlated to averages of Z700 teleconnections using 3 to 12 month windows at lead times from 0 to 12 months. Some of the Z700 teleconnections, that are not strongly correlated with ENSO, showed correlations with seasonal streamflow and precipitation comparable to the ones found with ENSO indicators. In general the results suggest that the teleconnections would not be useful in extending the lead time of ENSO-based precipitation and streamflow forecasts. However, there is additional information contained in the Z700 data that could potentially be incorporated into this type of forecast to improve the predictive skill in some regions. To illustrate this, a linear regression and an Artificial Neural Network model were used to produce seasonal precipitation and streamflow forecasts using ENSO indicators and Z700 teleconnections. It is expected that the incorporation of the Z700 teleconnections in ENSO-based forecasting models will improve the skill in the prediction of seasonal precipitation and streamflow in eastern Australia and in those South American regions were the ENSO signal is strong.