Warm season streamflow variability in the Korean Han River Basin: Links with atmospheric teleconnections

Abstract

AbstractWarm season (June–September) hydroclimatology is a key determinant of freshwater supplies in the Korean Peninsula. In the Han River Basin, nearly three‐fourths of annual discharge occurs during the warm season. Given the increased reliance on water supplies for numerous human and ecosystem functions, an integrated view of water supplies within the context of the regional hydroclimate will aid efforts to achieve water resources sustainability. To that end, this diagnostic study investigates several key aspects of the Han River hydrologic regime: (i) the warm season hydroclimatology; (ii) understanding the relative contribution of typhoon and non‐typhoon precipitation events to warm season streamflow; and (iii) relationships with large‐scale atmospheric teleconnections patterns and the implied seasonal predictability. Statistical analysis of modelled unimpaired streamflow indicates that the East Atlantic‐Western Russia (EA–WR) teleconnection pattern modulates the Han River streamflow during the warm season. Furthermore, a linear modelling approach using the EA–WR and East Atlantic (EA) teleconnection indices offers a useful empirical framework for understanding the systematic shifts in streamflow probability distributions. Based on these results, potential use of this information for multi‐objective water resources management, environmental flow prescriptions, proactive use of seasonal forecasts, and some open questions are briefly discussed. Copyright © 2010 Royal Meteorological Society