The influence of El Nino/Southern Oscillation on streamflow in Korea

The influence of El Nino/Southern Oscillation (ENSO) on Korean streamflows is investigated using a statistical technique, the composite analysis. This study uses the Troup Southern Oscillation Index (SOI) as a measure of ENSO and streamflow data measured at Andong gauging station in Korea. Three combinations of the SOI and streamflow data sets are considered: 1) the seasonal SOI and seasonal streamflow, the seasonal SOI and annual streamflow, and the annual SOT and annual streamflow. The traditional correlation analysis shows that cross correlations of the seasonal SOI with the seasonal streamflow are generally weak. The composite analysis, however, demonstrates that statistically significant responses of the Korean streamflows to the ENSO may exist although more data sets including different basins should be test to confirm the association. The results indicate that the traditional correlation analysis can mask significant links between the two variables.