Atlantic Ocean Sea Surface Temperatures and Southeast United States streamflow variability: Associations with the recent multi-decadal decline

Abstract

Unprecedented population growth combined with environmental and energy demands have led to water conflict in the Southeastern United States (SEUS). The states of Alabama, Florida, and Georgia have been engaged in litigation since 1990 on minimum in-stream flows to maintain ecosystems, fisheries and energy demands while satisfying a growing thirst in metropolitan Atlanta. A study of twenty-six unimpaired SEUS (Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, and Tennessee) streamflow stations identified a decreased pattern of flow over the past ∼25 years with more frequent dry periods being observed in the last several decades. When evaluating calendar year streamflow, a period of high streamflow in the 1970’s was followed by a consistent decrease in streamflow from the late 1980’s to present. The identification of Atlantic Ocean (AO) Sea Surface Temperature (SST) teleconnections with SEUS streamflow may prove valuable in explaining decadal patterns of streamflow variability. Previous studies have identified the Atlantic Multidecadal Oscillation (AMO) as being teleconnected with SEUS precipitation and streamflow. The current research applied the Singular Value Decomposition (SVD) statistical method to AO Sea Surface Temperatures (SSTs) and SEUS streamflow. Annual streamflow volumes from the twenty-six unimpaired SEUS streamflow stations (1952–2016) were selected as the hydrologic response while average AO SSTs were calculated for three different six month averages (January to June or JFMAMJ, April to September or AMJJAS, and July to December or JASOND) for the year (1951–2015) preceding streamflow. The results confirmed an SST region in the North Atlantic as being teleconnected with SEUS streamflow and that an observed multi-decadal increase in temperatures in this SST region may be associated with the observed recent multi-decadal decline in SEUS streamflow.