Oceanic response to Pliensbachian and Toarcian magmatic events: Implications from an organic-rich basinal succession in the NW Tethys

Abstract Based on the classical Ekman layer theory, a simple analytical solution of the steady flow induced by a stationary hurricane in a homogenous ocean is discussed. The model consists of flow converging in an inward spiral in the deeper layer and diverging in the upper layer. The simple analytical model indicates that both the upwelling flux and the horizontal transport increase linearly with increasing radius of maximum winds. Furthermore, they both have a parabolic relationship with the maximum wind speed. The Coriolis parameter also affects the upwelling flux: the response to a hurricane is stronger at low latitudes than that at middle latitudes. Numerical solutions based on a regional version of an ocean general circulation model are similar to the primary results obtained through the analytical solution. Thus, the simplifications made in formulating the analytical solution are reasonable. Although the analytical solution in this paper is sought for a rather idealized ocean, it can help to make results from the more complicated numerical model understandable. These conceptual models provide a theoretical limit structure of the oceanic response to a moving hurricane over a stratified ocean.

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Does the sensitivity of Southern Ocean circulation depend upon bathymetric details?

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2013.0050 ◽

2014 ◽

Vol 372 (2019) ◽

pp. 20130050 ◽

Cited By ~ 11

Author(s):

Andrew McC. Hogg ◽

David R. Munday

Keyword(s):

Southern Ocean ◽

Wind Stress ◽

Ocean Circulation ◽

Bottom Water ◽

Deep Ocean ◽

Ocean Eddies ◽

Oceanic Response ◽

Water Formation ◽

Circumpolar Current ◽

Bottom Water Formation

The response of the major ocean currents to changes in wind stress forcing is investigated with a series of idealized, but eddy-permitting, model simulations. Previously, ostensibly similar models have shown considerable variation in the oceanic response to changing wind stress forcing. Here, it is shown that a major reason for these differences in model sensitivity is subtle modification of the idealized bathymetry. The key bathymetric parameter is the extent to which the strong eddy field generated in the circumpolar current can interact with the bottom water formation process. The addition of an embayment, which insulates bottom water formation from meridional eddy fluxes, acts to stabilize the deep ocean density and enhances the sensitivity of the circumpolar current. The degree of interaction between Southern Ocean eddies and Antarctic shelf processes may thereby control the sensitivity of the Southern Ocean to change.

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The Oceanic Response to Large-Scale Atmospheric Disturbances

Journal of Physical Oceanography ◽

10.1175/1520-0485(1980)010<0411:tortls>2.0.co;2 ◽

1980 ◽

Vol 10 (3) ◽

pp. 411-429 ◽

Cited By ~ 145

Author(s):

J. Willebrand ◽

S. G. H. Philander ◽

R. C. Pacanowski

Keyword(s):

Large Scale ◽

Atmospheric Disturbances ◽

Oceanic Response

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A vertical-mode decomposition to investigate low-frequency internal motion across the Atlantic at 26° N

Ocean Science ◽

10.5194/os-8-345-2012 ◽

2012 ◽

Vol 8 (3) ◽

pp. 345-367 ◽

Cited By ~ 12

Author(s):

Z. B. Szuts ◽

J. R. Blundell ◽

M. P. Chidichimo ◽

J. Marotzke

Keyword(s):

Low Frequency ◽

Western Boundary ◽

Original Signal ◽

Baroclinic Mode ◽

Eastern Boundary ◽

Mode Decomposition ◽

Oceanic Response ◽

Vertical Density ◽

Baroclinic Modes ◽

Pressure Perturbations

Abstract. Hydrographic data from full-depth moorings maintained by the Rapid/\\-MOCHA project and spanning the Atlantic at 26° N are decomposed into vertical modes in order to give a dynamical framework for interpreting the observed fluctuations. Vertical modes at each mooring are fit to pressure perturbations using a Gauss-Markov inversion. Away from boundaries, the vertical structure is almost entirely described by the first baroclinic mode, as confirmed by high correlation between the original signal and reconstructions using only the first baroclinic mode. These first baroclinic motions are also highly coherent with altimetric sea surface height (SSH). Within a Rossby radius (45 km) of the western and eastern boundaries, however, the decomposition contains significant variance at higher modes, and there is a corresponding decrease in the agreement between SSH and either the original signal or the first baroclinic mode reconstruction. Compared to the full transport signal, transport fluctuations described by the first baroclinic mode represent <25 km of the variance within 10 km of the western boundary, in contrast to 60 km at other locations. This decrease occurs within a Rossby radius of the western boundary. At the eastern boundary, a linear combination of many baroclinic modes is required to explain the observed vertical density profile of the seasonal cycle, a result that is consistent with an oceanic response to wind-forcing being trapped to the eastern boundary.

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