OCEAN-ATMOSPHERE TELECONNECTIONS AND STREAMFLOW VARIABILITY IN THE UPPER ALLEGHENY RIVER BASIN, EASTERN UNITED STATES

The upper Allegheny River Basin (uARB) lies within a hydroclimatically sensitive region of Eastern North America. Annual peak flows are generated by cool season extratropical cyclones and snowmelt, warm season convective systems, and less frequently tropical cyclones. This study attempts to explore the impact of global atmospheric circulation on uARB streamflow through statistical analyses of hydrologic and climatologic datasets. Preliminary results suggest that streamflow variability throughout the uARB may be partially explained by linkages to ocean-atmosphere teleconnections (OATs). Three OATs have been identified as being at least partially linked to streamflow variability at four USGS-HCDN sites within the uARB: the Pacific North American Oscillation (PNA), North Atlantic Oscillation (NAO) and Arctic Oscillation (AO). The strongest correlation occurs between the PNA and streamflow during fall, winter and spring months; times of generally low streamflow variability. The NAO and AO appear to influence Upper Allegheny River streamflow during the cooler months of the year.

Consistent with other studies of the impact of OATs throughout Eastern North America, the relationships between streamflow and the PNA, NAO, and AO revealed in this study suggest an influence of short-term climate variability on streamflow on monthly and seasonal bases. Unfortunately, only a portion of streamflow variability can be fully be explained by teleconnections alone, but PNA and NAO influences on zonal versus meridional atmospheric flow, thus air mass trajectories do appear to be a piece of the puzzle. This information could be useful in seasonal streamflow forecasting.