Characteristics of an Advective Marine Heatwave in the Middle Atlantic Bight in Early 2017

Abstract

There has been wide interest in Marine Heatwaves and their ecological consequences in recent years. Most analyses have focused on remotely sensed sea surface temperature data due to the temporal and spatial coverage it provides in order to establish the presence and duration of Heatwaves. Using hydrographic data from a variety of sources, we show that an advective Marine Heatwave was initiated by an event in late December of 2016 south of New England, with temperature anomalies measuring up to 6 • C and salinity anomalies exceeding 1 PSU. Similar features were observed off of New Jersey in February 2017, and are associated with the Shelfbreak Front migrating from its normal position to mid-shelf or further onshore. Shelf water of 34 PSU was observed just north of Cape Hatteras at the 30 m isobath and across the continental shelf in late April 2017. These observations reveal that the 2017 Marine Heatwave was associated with a strong positive salinity anomaly, that its total duration was approximately 4 months, and its advective path extended roughly 850 km along the length of the continental shelf in the Middle Atlantic Bight. The southward advective velocity implied by the arrival north of Cape Hatteras is consistent with previous estimates of alongshelf velocity for the region. The origin of this Marine Heatwave is likely related to cross-shelf advection driven by the presence of a Warm Core Ring adjacent to the shelfbreak south of New England.

A Census of the Warm‐Core Rings of the Gulf Stream: 1980–2017

“…Studies such as Myers and Drinkwater (1989) can be revisited to understand the impact of the larger number of WCRs (after the regime shift in 2000) on the various groundfish populations in the GOM and GB area. In fact, such a high number of WCRs in the slope water might have impacted the ecosystem of the GOM/GB and MAB by making them even warmer and saltier frequently in the first two decades of the 21st century as reported recently by Gawarkiewicz et al (2019). An investigation for identifying similar regime shift in the recruitment structure of ichthyoplankton and zooplankton is underway.…”

Understanding physical drivers of the 2015/16 marine heatwaves in the Northwest Atlantic

“…Large amplitude meanders and WCRs can bring warm salty water into close proximity to the continental slope and shelf break 11 , 12 and can affect both the Shelfbreak Jet as well as shelf temperature 13 . Gawarkiewicz et al 14 found that an ocean-driven MHW along the continental shelf of the Mid-Atlantic Bight in 2017 was forced by the presence of a WCR, which resulted in cross-shelf transport of warm and salty Gulf Stream water. Additionally, a northward shift of the Gulf Stream toward the Tail of Grand Banks, where it potentially blocks the equatorward-flowing Labrador Current has been shown to increase salinity and temperature of subsurface waters on the Northwest Atlantic Shelf, “downstream” (southwest) of this interaction location 15 , 16 .…”

Forecasting the Gulf Stream Path Using Buoyancy and Wind Forcing Over the North Atlantic

“…This path variability has been linked to multiple processes spanning from fisheries (Nye et al., 2011) to atmospheric events (Joyce et al., 2009) and is often interpreted as an indicator of climate change (Caesar et al., 2018; Zhang et al., 2019). In particular recent rapid changes in the northwest Atlantic water properties and ecosystem, responses have been linked to the variations of the GS path and its instabilities (Andres, 2016; Brickman et al., 2018; Gangopadhyay et al., 2019; Gawarkiewicz et al., 2012, 2018, 2019; Mills et al., 2013; Pershing et al., 2015; Silver et al., 2021).…”