Eastern U.S. summer streamflow during extreme phases of the North Atlantic oscillation

Abstract

Numerous studies have suggested streamflow discharge in the conterminous U.S. has been increasing, particularly in the east starting in the latter half of the 20th century. Northern Hemisphere (NH) hydroclimatic variability has been connected to shifts in large‐scale atmospheric teleconnection patterns. This study ascertained the spatial and temporal influences of the extreme phases of the North Atlantic Oscillation (NAO) on interannual streamflow variability across the eastern U.S. during the summer season. We also assessed the presence of any delayed streamflow responses to NAO configurations during previous spring (March‐April‐May) and winter (December‐January‐February) seasons across the study area. Methods of inquiry included the use of various statistical and compositing analyses applied to records of mean daily summer streamflow obtained from the Hydro‐Climatic Data Network between 1950 and 2010. Results of this study suggest that summer streamflow across eastern U.S. may be related to and thus potentially predicted from the NAO up to three seasons in advance, information of significant hydrologic consequences for the area. Depending upon the season and geographic location, the relationships may be both linear and nonlinear in nature and may be masked by the presence of temporal trends in the index. Summer streamflow across the eastern U.S., in general, displays greatest response to the negative phase of the NAO during the previous winter and the concurrent summer seasons. Geographically, the greatest potential for predictability exists across the Northeast where cohesive responses to NAO exist in all three seasons, winter, spring, and summer.

Hydroclimatic flood trends in the northeastern United States and linkages with large-scale atmospheric circulation patterns

“…We recognize that it is more commonplace for hydroclimatic studies that identify a neutral NAO condition to identify larger index thresholds (e.g. ±0.5 or ±1) (Hurrell 2003, Coleman andBudikova 2013). However, our purpose is not to identify high/low, or 'extreme', phases of the NAO.…”

“…However, recent research by Steinschneider and Brown (2011) and Coleman and Budikova (2013) suggest mechanisms by which such gains may be preserved and/or enhanced into the following water year. For example, Steinschneider and Brown (2011) found a positive correlation between the winter NAO phase and late summer one-and seven-day low flow in the Connecticut River basin in New England.…”

Spatial and Temporal Variations in Eastern U.S. Hydrology: Responses to Global Climate Variability

“…During high‐NAO winters, the extension of Bermuda/Azores high to the northeastern U.S. blocks the invasion of the polar jet stream and the mid‐latitude winter storms, which results in the decrease in winter precipitation in northeastern U.S. (Ning and Bradley, ) and then alters the streamflow in this region. Coleman and Budikova () found that the NAO, especially the negative phase, can impact the eastern U.S. summer streamflow up to three seasons in advance. During positive NAO years, the southerly wind anomalies induced by the east‐west pressure gradient and the blocked invasion of polar jet stream due to extension of Bermuda/Azores high leads to positive temperature anomalies in the northeastern U.S.…”

A Review of Water Quality Responses to Air Temperature and Precipitation Changes 1: Flow, Water Temperature, Saltwater Intrusion

“…). In the western U.S. and Alaska, the North Atlantic Oscillation and Pacific Decadal Oscillation (PDO) have also been linked to sudden changes in weather which altered streamflow (Woo and Thorne ; Coats ; Coleman and Budikova ). In the southeastern U.S., complex patterns linking different decadal oscillations to seasonal differences in flow have been described, emphasizing the important link between climate and streamflow (Sheldon and Burd ).…”