Abstract
AbstractA decade (2007–2016) of hourly 6‐km‐resolution maps of the surface currents across the Mid‐Atlantic Bight (MAB) generated by a regional‐scale High Frequency Radar network are used to reveal new insights into the spatial patterns of the annual and seasonal mean surface flows. Across the 10‐year time series, temporal means and interannual and intra‐annual variability are used to quantify the variability of spatial surface current patterns. The 10‐year annual mean surface flows are weaker and mostly cross‐shelf near the coast, increasing in speed and rotating to more alongshore directions near the shelfbreak, and increasing in speed and rotating to flow off‐shelf in the southern MAB. The annual mean surface current pattern is relatively stable year to year compared to the hourly variations within a year. The 10‐year seasonal means exhibit similar current patterns, with winter and summer more cross‐shore while spring and fall transitions are more alongshore. Fall and winter mean speeds are larger and correspond to when mean winds are stronger and cross‐shore. Summer mean currents are weakest and correspond to a time when the mean wind opposes the alongshore flow. Again, intra‐annual variability is much greater than interannual, with the fall season exhibiting the most interseasonal variability in the surface current patterns. The extreme fall seasons of 2009 and 2011 are related to extremes in the wind and river discharge events caused by different persistent synoptic meteorological conditions, resulting in more or less rapid fall transitions from stratified summer to well‐mixed winter conditions.
Highlights
The coastal ocean is an intricate system that forms the boundary between the land and the deep ocean
The isobaths are roughly parallel to the coastline except near the Hudson Shelf Valley (HSV) and the many shelfbreak canyons distributed throughout the Mid‐Atlantic Bight (MAB)
We examined the daily distribution of synoptic types for the fall season (September/October/November 2007–2016), covering the 10 years of the HF radar record
Summary
The coastal ocean is an intricate system that forms the boundary between the land and the deep ocean. For shallow and wide continental shelves, such as those on the U.S East Coast, dynamical factors such as ROARTY ET AL. The Middle Atlantic Bight (MAB) supports a complex marine ecosystem, and it has been a focus of coastal oceanographic research since the early 1900s (Bigelow & Sears, 1935). The continental shelf of the MAB extends from Cape Hatteras, NC, in the south to Georges Bank off Cape Cod, MA, in the north. The width of the shelf gradually decreases from ~120 km south of Cape Cod down to ~40 km east of Cape Hatteras.
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