Search Results
called the mass-adjusted three-dimensional wind field (MATHEW; Sherman 1978 ). Further examples include such commonly used models as the Stochastic Time Inverted Lagrangian Transport model (STILT; Lin et al. 2003 ), “FLEXPART” ( Stohl et al. 1998 ), the Hybrid Particle and Concentration Transport Model (HYPACT; Uliasz 1996 ), Hybrid Single Particle Lagrangian Integrated Trajectory model (HYSPLIT; Draxler and Hess 1998 ), and Numerical Atmospheric Dispersion Modeling Environment (NAME; Ryall and
called the mass-adjusted three-dimensional wind field (MATHEW; Sherman 1978 ). Further examples include such commonly used models as the Stochastic Time Inverted Lagrangian Transport model (STILT; Lin et al. 2003 ), “FLEXPART” ( Stohl et al. 1998 ), the Hybrid Particle and Concentration Transport Model (HYPACT; Uliasz 1996 ), Hybrid Single Particle Lagrangian Integrated Trajectory model (HYSPLIT; Draxler and Hess 1998 ), and Numerical Atmospheric Dispersion Modeling Environment (NAME; Ryall and
.g., Anderson 2009 ; Michel et al. 2013 ). Understanding the transport and retention of hazardous pollutants and biological matter in the nearshore region is important for reasons ranging from human health factors to sustaining ecosystems (e.g., Shahidul Islam and Tanaka 2004 ; Grant et al. 2005 ). Studies of cross-shore circulation over the inner shelf, focusing on wave-driven flows (i.e., during weak wind forcing), demonstrate the importance of the onshore Lagrangian Stokes drift u St ( z ) associated
.g., Anderson 2009 ; Michel et al. 2013 ). Understanding the transport and retention of hazardous pollutants and biological matter in the nearshore region is important for reasons ranging from human health factors to sustaining ecosystems (e.g., Shahidul Islam and Tanaka 2004 ; Grant et al. 2005 ). Studies of cross-shore circulation over the inner shelf, focusing on wave-driven flows (i.e., during weak wind forcing), demonstrate the importance of the onshore Lagrangian Stokes drift u St ( z ) associated
eddy transport is comparable in magnitude to the transport induced by large-scale circulations and can lead to the redistribution of heat, thus having a significant impact on global climate change ( Dong et al. 2014 ; Z.-G. Zhang et al. 2014 ; Sun et al. 2019 ; Meijers et al. 2007 ). However, recent studies show that the magnitude of eddy-induced transport can vary significantly depending on the mesoscale eddy detection technique that is used ( Beron-Vera et al. 2018 , 2013 ; Liu et al. 2019
eddy transport is comparable in magnitude to the transport induced by large-scale circulations and can lead to the redistribution of heat, thus having a significant impact on global climate change ( Dong et al. 2014 ; Z.-G. Zhang et al. 2014 ; Sun et al. 2019 ; Meijers et al. 2007 ). However, recent studies show that the magnitude of eddy-induced transport can vary significantly depending on the mesoscale eddy detection technique that is used ( Beron-Vera et al. 2018 , 2013 ; Liu et al. 2019
field of the western Mediterranean Sea, obtained from a three-dimensional model simulation under climatological atmospheric forcing. Our aim is, first, to find the location and nature of the Lagrangian structures associated with the so-called Balearic Current that serve to maintain the North Balearic Front. And, second, to show that transport mechanisms, in particular the so-called turnstile mechanism previously identified in abstract dynamical systems ( Channon and Lebowitz 1980 ; Bartlett 1982
field of the western Mediterranean Sea, obtained from a three-dimensional model simulation under climatological atmospheric forcing. Our aim is, first, to find the location and nature of the Lagrangian structures associated with the so-called Balearic Current that serve to maintain the North Balearic Front. And, second, to show that transport mechanisms, in particular the so-called turnstile mechanism previously identified in abstract dynamical systems ( Channon and Lebowitz 1980 ; Bartlett 1982
hurricane-induced mixing run. We show that the LOM is able to reproduce essential features of large-scale ocean circulation and exploit the advantages of the Lagrangian model to present insightful and unique diagnostics of the oceanic transport of heat and tracers. a. Meridional overturning circulation In each experiment, the model is spun up for 1000 years. The circulation reaches a quasi-steady state after 200 years of integration and does not change significantly afterward. To determine time
hurricane-induced mixing run. We show that the LOM is able to reproduce essential features of large-scale ocean circulation and exploit the advantages of the Lagrangian model to present insightful and unique diagnostics of the oceanic transport of heat and tracers. a. Meridional overturning circulation In each experiment, the model is spun up for 1000 years. The circulation reaches a quasi-steady state after 200 years of integration and does not change significantly afterward. To determine time
affected by vertical advection alone, trace analysis approximates the Lagrangian mean vertical velocity well. However, the zonal mean constituent distribution is not determined solely by the mean meridional circulation; it is also a function of how much meridional and vertical mixing is occurring. These transports can lead to errors in the assumptions of trace analysis. We found some disagreements in the mean vertical velocity around the polar vortex between the dynamical and trace analyses. Dynamical
affected by vertical advection alone, trace analysis approximates the Lagrangian mean vertical velocity well. However, the zonal mean constituent distribution is not determined solely by the mean meridional circulation; it is also a function of how much meridional and vertical mixing is occurring. These transports can lead to errors in the assumptions of trace analysis. We found some disagreements in the mean vertical velocity around the polar vortex between the dynamical and trace analyses. Dynamical
) formulation of thickness-weighted horizontal and vertical velocities because the overturning circulation is the net Lagrangian transport of water parcels advected by both the Eulerian and time-varying, eddying, flow. We need the thickness-weighted velocities because the mean velocities are not always parallel to the mean buoyancy surfaces b ¯ . In contrast, the thickness-weighted velocities ensure that the particles remain on the mean buoyancy surfaces. For instance, the Reynolds’ heat flux implies
) formulation of thickness-weighted horizontal and vertical velocities because the overturning circulation is the net Lagrangian transport of water parcels advected by both the Eulerian and time-varying, eddying, flow. We need the thickness-weighted velocities because the mean velocities are not always parallel to the mean buoyancy surfaces b ¯ . In contrast, the thickness-weighted velocities ensure that the particles remain on the mean buoyancy surfaces. For instance, the Reynolds’ heat flux implies
CWV. Since water vapor is concentrated in the lower troposphere, this velocity reflects the circulation near the boundary. It can be further decomposed into rotational and divergent components: with ∇ ⋅ v ψ = 0. Noting that we can rewrite (2) as The additional term R represents the numerical dissipation of CWV in the model, reflecting the diffusive effect of the third-order transport scheme on scalars used in MPAS ( Skamarock and Gassmann 2011 ). Except for the extra E − P term, (3
CWV. Since water vapor is concentrated in the lower troposphere, this velocity reflects the circulation near the boundary. It can be further decomposed into rotational and divergent components: with ∇ ⋅ v ψ = 0. Noting that we can rewrite (2) as The additional term R represents the numerical dissipation of CWV in the model, reflecting the diffusive effect of the third-order transport scheme on scalars used in MPAS ( Skamarock and Gassmann 2011 ). Except for the extra E − P term, (3
across the surf-zone edge into the inner shelf ( Figs. 12e,f ); consequently, the inner-shelf tracer concentration is elevated remarkably ( Figs. 11c,d ). Particularly with wave streaming, the tracers are transported farther offshore by the inner-shelf Lagrangian overturning circulation ( Figs. 11c and 12c ). 4. Discussion a. Sensitivity to bottom roughness Wave streaming is parameterized with a streaming force given by Eqs. (A5) and (A6) , in which the bottom roughness height z o is crucial
across the surf-zone edge into the inner shelf ( Figs. 12e,f ); consequently, the inner-shelf tracer concentration is elevated remarkably ( Figs. 11c,d ). Particularly with wave streaming, the tracers are transported farther offshore by the inner-shelf Lagrangian overturning circulation ( Figs. 11c and 12c ). 4. Discussion a. Sensitivity to bottom roughness Wave streaming is parameterized with a streaming force given by Eqs. (A5) and (A6) , in which the bottom roughness height z o is crucial
eastern part of the South Atlantic in the Agulhas retroflection area is reached, waters take a similar path as the warm route in the westward SEC and then NBC. Fig . 2. Lagrangian streamfunctions representing net volume transport (color scale; Sv) pathways between (a) AC section or (b) DP section and 6.7°S with contour intervals of 1 Sv in (a) and 0.2 Sv in (b). Negative values indicate counterclockwise circulation. Figure 3 shows the typical transit times of each route from their entrance in
eastern part of the South Atlantic in the Agulhas retroflection area is reached, waters take a similar path as the warm route in the westward SEC and then NBC. Fig . 2. Lagrangian streamfunctions representing net volume transport (color scale; Sv) pathways between (a) AC section or (b) DP section and 6.7°S with contour intervals of 1 Sv in (a) and 0.2 Sv in (b). Negative values indicate counterclockwise circulation. Figure 3 shows the typical transit times of each route from their entrance in
