Dynamic observations in the Hampton Roads region: how surface currents at the mouth of Chesapeake Bay may be linked with winds, water level, river discharge and remote forcing from the Gulf Stream

The study analyzed nine years of hourly surface currents measured by high-frequency Coastal Ocean Dynamics Application Radar (CODAR) near the mouth of Chesapeake Bay (CB) [1–3]. These observations, available in near real-time, have many practical usages for search and rescue, tracking pollution, navigation, Navy operations, and assimilation into numerical ocean models. It is important to understand the dynamics of the CB and to better deal with the impacts from climate change, such as accelerated sea level rise and flooding [4–7]. So far, not much research has been done on the relation between the surface current data and other observations such as coastal sea level, local wind forcing and river discharge into CB. Recent studies also show potential remote influence on the region from variations in the Atlantic Ocean circulation, and in particular, studies found that when the Gulf Stream (GS) slows down, coastal sea level along the U.S. Mid-Atlantic coast rises [8]. Therefore, the study examined potential connections between the observed transport of the Florida Current [9] (the upstream part of the GS) and the radar surface currents. Various analysis methods were implemented to find links between the different observations, and variability was assessed on a wide range of time scales, from hourly and monthly variations to interannual and longer trends. The results show how different forcings impact the surface currents on different time scales and provide better understanding of dynamic observations in the CB.