Effects of El-Niño and La-Niña Sea Surface Temperature Anomalies on Annual Precipitations and Streamflow Discharges in Southeastern United States

Statistical analysis shows that El Nino and La Nina are partially responsible for the amounts of annual precipitation and annual streamflow discharges in Gulf Atlantic hydrologic unit of Southeast United States. The study is based on 61-year records of precipitation and streamflow discharge stations spread across the region. The cross-correlation coefficients for both the sea surface temperature (SST) anomalies and precipitation, and SST anomalies and streamflow were calculated after the data series were prewhitened by an Autoregressive Integrated Moving Average (ARIMA) model (2,0,3). The cross-correlations between SST anomalies and both precipitations and streamflow discharges were positively significant. Using statistical relationship established relating SST anomalies with precipitation and streamflow in the area; comparison analyses of observed and filtered data series are performed at locations where there is significant influence of El Nino - Southern Oscillation (ENSO) on precipitations and streamflow discharges in the region. The degree of influence ENSO has on each hydrologic series hence can be predicted for different water sheds in the area. This can be of immense help for water management strategy and planning in the region.