Search Results
1. Introduction Submarine canyons are a common feature along continental shelves. They are estimated to cover approximately 20% of the shelf along the west coast of North America ( Hickey 1995 ). Canyons can be efficient generators of internal tides (internal gravity waves with tidal frequencies) through scattering of the barotropic tides from sloping topography ( Bell 1975 ; Baines 1982 ). They are also thought to trap internal waves from outside the canyon, through reflection from the
1. Introduction Submarine canyons are a common feature along continental shelves. They are estimated to cover approximately 20% of the shelf along the west coast of North America ( Hickey 1995 ). Canyons can be efficient generators of internal tides (internal gravity waves with tidal frequencies) through scattering of the barotropic tides from sloping topography ( Bell 1975 ; Baines 1982 ). They are also thought to trap internal waves from outside the canyon, through reflection from the
1. Introduction This paper examines the resonance of diurnal tides in the open and coastal oceans and the coupling between the open-ocean and coastal diurnal tides. We are motivated by the inherent interest in understanding the global tidal system and by recent studies which strongly suggest that tides of the ice age, during which lower sea levels implied a much reduced area of continental shelves, were much larger than those of today (e.g., Thomas and Sündermann 1999 ; Egbert et al. 2004
1. Introduction This paper examines the resonance of diurnal tides in the open and coastal oceans and the coupling between the open-ocean and coastal diurnal tides. We are motivated by the inherent interest in understanding the global tidal system and by recent studies which strongly suggest that tides of the ice age, during which lower sea levels implied a much reduced area of continental shelves, were much larger than those of today (e.g., Thomas and Sündermann 1999 ; Egbert et al. 2004
1. Introduction The generation of internal tides at ridges, seamounts, and island chains is an important energy pathway from the barotropic tide to mixing scales. The global distribution of deep-ocean internal tides has been examined with altimetric data, which has emphasized the time-independent or coherent (phase locked) component of the energetic M 2 semidiurnal tidal frequency ( Ray and Mitchum 1998 ). In contrast, in situ measurements of internal tides typically highlight the sizeable
1. Introduction The generation of internal tides at ridges, seamounts, and island chains is an important energy pathway from the barotropic tide to mixing scales. The global distribution of deep-ocean internal tides has been examined with altimetric data, which has emphasized the time-independent or coherent (phase locked) component of the energetic M 2 semidiurnal tidal frequency ( Ray and Mitchum 1998 ). In contrast, in situ measurements of internal tides typically highlight the sizeable
1. Introduction Most of the internal tide energy generated at tall, steep, midocean topography radiates away as low-vertical-mode internal waves ( Llewellyn Smith and Young 2003 ; St. Laurent et al. 2003 ). These energetic M 2 low-mode internal tides have been observed directly ( Dushaw et al. 1995 ; Feng et al. 1998 ; Lozovatsky et al. 2003 ; Dushaw 2006 ; Alford et al. 2007 ; Rainville and Pinkel 2006a , b ) and with satellite altimetry ( Ray and Mitchum 1997 ; Ray and Cartwright
1. Introduction Most of the internal tide energy generated at tall, steep, midocean topography radiates away as low-vertical-mode internal waves ( Llewellyn Smith and Young 2003 ; St. Laurent et al. 2003 ). These energetic M 2 low-mode internal tides have been observed directly ( Dushaw et al. 1995 ; Feng et al. 1998 ; Lozovatsky et al. 2003 ; Dushaw 2006 ; Alford et al. 2007 ; Rainville and Pinkel 2006a , b ) and with satellite altimetry ( Ray and Mitchum 1997 ; Ray and Cartwright
1. Introduction As tides enter basins, a variety of interactions modify the tidal signal including friction, the earth’s rotation, and bathymetry. Early works on co-oscillating tides found that observed tidal signals were superpositions of oppositely traveling Kelvin waves ( Taylor 1921 ) and that energy was absorbed at the head of basins which accounted for the observed dissipation of tidal energy ( Hendershott and Speranza 1971 ). As friction becomes important, the phase difference between
1. Introduction As tides enter basins, a variety of interactions modify the tidal signal including friction, the earth’s rotation, and bathymetry. Early works on co-oscillating tides found that observed tidal signals were superpositions of oppositely traveling Kelvin waves ( Taylor 1921 ) and that energy was absorbed at the head of basins which accounted for the observed dissipation of tidal energy ( Hendershott and Speranza 1971 ). As friction becomes important, the phase difference between
1. Introduction “Radiational tides,” a term that harkens back to Munk and Cartwright (1966) , refers to those tidal constituents—or components of constituents—that are forced ultimately by solar radiation rather than by the gravitational tidal potential. Although there was some early confusion about what this meant ( Godin 1986 ), it is now clear that the proximate driver of radiational ocean tides is loading by atmospheric pressure tides, which are themselves generated by insolation
1. Introduction “Radiational tides,” a term that harkens back to Munk and Cartwright (1966) , refers to those tidal constituents—or components of constituents—that are forced ultimately by solar radiation rather than by the gravitational tidal potential. Although there was some early confusion about what this meant ( Godin 1986 ), it is now clear that the proximate driver of radiational ocean tides is loading by atmospheric pressure tides, which are themselves generated by insolation
1. Introduction Internal tides, or tidally generated internal waves, are a ubiquitous feature of the World Ocean, generated when the large-scale barotropic tide flows over rough seafloor topography. The internal waves are generated at the tidal frequency, or its harmonics ( Bell 1975a ), and their horizontal wavelength is determined by the scale of the local topography. The structure and behavior of these waves depends on whether their vertical wavelength is small or large compared with the
1. Introduction Internal tides, or tidally generated internal waves, are a ubiquitous feature of the World Ocean, generated when the large-scale barotropic tide flows over rough seafloor topography. The internal waves are generated at the tidal frequency, or its harmonics ( Bell 1975a ), and their horizontal wavelength is determined by the scale of the local topography. The structure and behavior of these waves depends on whether their vertical wavelength is small or large compared with the
1. Introduction When astronomically forced barotropic tides flow over bathymetric features, they generate baroclinic internal tides. The conversion is particularly efficient when barotropic flow is directed across large bathymetric obstacles ( St. Laurent et al. 2003 ; Garrett and Kunze 2007 ), such as the Hawaiian Ridge ( Ray and Cartwright 2001 ; Merrifield et al. 2001 ; Rudnick et al. 2003 ), the Aleutian Ridge ( Cummins et al. 2001 ), and Mendocino Escarpment ( Althaus et al. 2003 ), but
1. Introduction When astronomically forced barotropic tides flow over bathymetric features, they generate baroclinic internal tides. The conversion is particularly efficient when barotropic flow is directed across large bathymetric obstacles ( St. Laurent et al. 2003 ; Garrett and Kunze 2007 ), such as the Hawaiian Ridge ( Ray and Cartwright 2001 ; Merrifield et al. 2001 ; Rudnick et al. 2003 ), the Aleutian Ridge ( Cummins et al. 2001 ), and Mendocino Escarpment ( Althaus et al. 2003 ), but
1. Introduction An early association of tides and climate was based on energetics. Cold, dense water formed in the North Atlantic would fill up the global oceans in a few thousand years were it not for downward mixing from the warm surface layers. Mixing a stratified fluid takes energy; the required rate of energy expenditure was estimated at 2 TW ( Munk and Wunsch 1998 ). Global tidal dissipation is 3.5 TW, two-thirds in marginal seas, one-third in the pelagic 1 oceans, suggesting a tidal
1. Introduction An early association of tides and climate was based on energetics. Cold, dense water formed in the North Atlantic would fill up the global oceans in a few thousand years were it not for downward mixing from the warm surface layers. Mixing a stratified fluid takes energy; the required rate of energy expenditure was estimated at 2 TW ( Munk and Wunsch 1998 ). Global tidal dissipation is 3.5 TW, two-thirds in marginal seas, one-third in the pelagic 1 oceans, suggesting a tidal
1. Introduction The purpose of this paper is to investigate the effects of mesoscale currents on internal tide propagation. This is motivated by observations of semidiurnal currents in the Kauai Channel ( Chavanne et al. 2010 , hereafter Part I ) during the Hawaii Ocean Mixing Experiment (HOME; Rudnick et al. 2003 ; Pinkel and Rudnick 2006 ). Part I compares the observed coherent (i.e., phase locked with astronomical forcing) semidiurnal currents with numerical predictions of the tides in
1. Introduction The purpose of this paper is to investigate the effects of mesoscale currents on internal tide propagation. This is motivated by observations of semidiurnal currents in the Kauai Channel ( Chavanne et al. 2010 , hereafter Part I ) during the Hawaii Ocean Mixing Experiment (HOME; Rudnick et al. 2003 ; Pinkel and Rudnick 2006 ). Part I compares the observed coherent (i.e., phase locked with astronomical forcing) semidiurnal currents with numerical predictions of the tides in
