Evolution of Denmark Strait overflow cyclones and their relationship to overflow surges

Thumbnail Image
Date
2020-02-06
Authors
Almansi, Mattia
Haine, Thomas W. N.
Gelderloos, Renske
Pickart, Robert S.
Linked Authors
Alternative Title
Date Created
Location
DOI
10.1029/2019GL086759
Replaced By
Keywords
Denmark Strait overflow
DSO cyclones
Boluses
Pulses
Abstract
Mesoscale features present at the Denmark Strait sill regularly enhance the volume transport of the Denmark Strait overflow (DSO). They are important for the Atlantic Meridional Overturning Circulation and ultimately, for the global climate system. Using a realistic numerical model, we find new evidence of the causal relationship between overflow surges (i.e., mesoscale features associated with high‐transport events) and DSO cyclones observed downstream. Most of the cyclones form at the Denmark Strait sill during overflow surges and, because of potential vorticity conservation and stretching of the water column, grow as they move equatorward. A fraction of the cyclones form downstream of the sill, when anticyclonic vortices formed during high‐transport events start collapsing. Regardless of their formation mechanism, DSO cyclones weaken starting roughly 150 km downstream of the sill, and potential vorticity is only materially conserved during the growth phase.
Description
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Almansi, M., Haine, T. W. N., Gelderloos, R., & Pickart, R. S. Evolution of Denmark Strait overflow cyclones and their relationship to overflow surges. Geophysical Research Letters, 47(4), (2020): e2019GL086759, doi:10.1029/2019GL086759.
Embargo Date
Citation
Almansi, M., Haine, T. W. N., Gelderloos, R., & Pickart, R. S. (2020). Evolution of Denmark Strait overflow cyclones and their relationship to overflow surges. Geophysical Research Letters, 47(4), e2019GL086759.
Cruises
Cruise ID
Cruise DOI
Vessel Name
Except where otherwise noted, this item's license is described as Attribution 4.0 International