Chen, K., Gawarkiewicz, G., Yang, J., 2022. Mesoscale and submesoscale shelf-ocean exchanges initialize an advective Marine Heatwave. Journal of Geophysical Research: Oceans, 127, e2021JC017927. https://doi.org/10.1029/2021JC017927

Bottom intensified intrusion as revealed by the evolution of the salinity field (color) near a seabed trough on the southern New England shelf. Density field is in gray contours at an interval 0.2 kg m-3. This localized bottom intrusion is a key process leading to a subsurface, advective Marine Heatwave in early 2017, the driving processes of which is recently investigated in this study. Based on observations and a new high-resolution regional circulation model, this work showed that smaller scale cyclonic eddies in addition to the traditionally considered Gulf Stream warm core rings played an important role in preconditioning the outer continental shelf via processes including along-isobath pressure gradient change and frontogenesis. Subsequently, strong and persistent upwelling wind in late January 2017 drove a bottom intensified intrusion from the outer shelf to the inner shelf. In contrast to earlier 2D consideration of the wind-driven shelf-ocean exchange and the migration of the shelfbreak front, the most salient feature of the bottom intrusion during January 2017 is localized along a bathymetric feature. This work highlights the effectiveness of the combination of offshore eddies and upwelling wind in driving large-distance onshore intrusions leading to subsurface, advective Marine Heatwaves. It also shows that consideration of three-dimensionality, such as the representation of the along-shelf bathymetry, is essential for a comprehensive understanding of the shelf-ocean exchange and thus the origination of extreme variability over the continental shelf.   Figure provided by Ke Chen.