Role of Nonlinear Eddy Forcing in the Dynamics of Multiple Zonal Jets

2017 ◽  
pp. 161-178
Author(s):  
Igor Kamenkovich ◽  
Pavel Berloff
Keyword(s):  
Zonal Jets

scholarly journals Galileo: Close-up Views of Jupiter’s Dynamic Atmosphere

2002 ◽  
Vol 12 ◽  
pp. 602-605 ◽  
Author(s):  
Ashwin R. Vasavada
Keyword(s):  
Near Infrared ◽  
Moist Convection ◽  
Entry Site ◽  
Zonal Jets ◽  
Night Side ◽  
New Ideas ◽  
Water Cloud ◽  
Galileo Probe ◽  
Auroral Phenomena

AbstractThe Galileo spacecraft’s Solid State Imager (SSI) has been returning mosaics of Jupiter since 1996. The combination of high spatial resolution, broad spectral range, and short mosaic time steps has revealed a dynamic, vertically extended cloud structure not detectable by Voyager. These data have stimulated new analyses of major features such as zonal jets, the Great Red Spot, White Ovals, and the Galileo Probe entry site. Near-infrared images have provided fundamental constraints on the vertical structure of clouds and hazes, including the first imaging of a water cloud. Results from night side imaging include an extensive search for lightning, the first matching of lightning events to day side storm clouds, and the first spectral and spatial measurements of visible-wavelength auroral phenomena (not discussed here, see Vasavada et al. 2000). The identification of several tall, energetic storm systems at specific latitudes has led to new ideas about the role of moist convection in Jupiter’s atmospheric energetics.

scholarly journals Role of Eddies in the Maintenance of Multiple Jets Embedded in Eastward and Westward Baroclinic Shears

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 91 ◽  
Author(s):  
Hemant Khatri ◽  
Pavel Berloff
Keyword(s):  
Large Scale ◽  
Bottom Layer ◽  
Relative Vorticity ◽  
Global Ocean ◽  
Dynamic Interactions ◽  
Zonal Jets ◽  
Eddy Dynamics ◽  
Quasigeostrophic Model ◽  
The Impact

Multiple zonal jets observed in many parts of the global ocean are often embedded in large-scale eastward and westward vertically sheared background flows. Properties of the jets and ambient eddies, as well as their dynamic interactions, are found to be different between eastward and westward shears. However, the impact of these differences on overall eddy dynamics remains poorly understood and is the main subject of this study. The roles of eddy relative vorticity and buoyancy fluxes in the maintenance of oceanic zonal jets are studied in a two-layer quasigeostrophic model. Both eastward and westward uniform, zonal vertically sheared cases are considered in the study. It is shown that, despite the differences in eddy structure and local characteristics, the fundamental dynamics are essentially the same in both cases: the relative-vorticity fluxes force the jets in the entire fluid column, and the eddy-buoyancy fluxes transfer momentum from the top to the bottom layer, where it is balanced by bottom friction. It is also observed that the jets gain more energy via Reynolds stress work in the layer having a positive gradient in the background potential vorticity, and this is qualitatively explained by a simple reasoning based on Rossby wave group velocity.

scholarly journals Intra-annual Rossby waves destabilization as a potential driver of Low-Latitude Zonal Jets – Barotropic dynamics

2020 ◽  
Author(s):  
Audrey Delpech ◽  
Claire Ménesguen ◽  
Yves Morel ◽  
Leif Thomas ◽  
Frédéric Marin ◽  
...  
Keyword(s):  
Rossby Waves ◽  
Secondary Wave ◽  
Low Latitude ◽  
Physical Mechanisms ◽  
Zonal Jets ◽  
Low Latitudes ◽  
Mean Circulation ◽  
Residual Mean Circulation ◽  
Selection Of

AbstractAt low latitudes in the ocean, the deep currents are shaped into narrow jets flowing eastward and westward, reversing periodically with latitude between 15°S and 15°N. These jets are present from the thermocline to the bottom. The energy sources and the physical mechanisms responsible for their formation are still debated and poorly understood. This study explores the role of the destabilization of intra-annual equatorial waves in the jets formation process, as these waves are known to be an important energy source at low latitudes. The study focuses particularly on the role of barotropic Rossby waves as a first step towards understanding the relevant physical mechanisms. It is shown from a set of idealized numerical simulations and analytical solutions that Non-Linear Triad Interactions (NLTI) play a crucial role in the transfer of energy towards jet-like structures (long waves with short meridional wavelengths) that induce a zonal residual mean circulation. The sensitivity of the instability emergence and the scale selection of the jet-like secondary wave to the forced primary wave is analyzed. For realistic amplitudes around 5-20 cm s−1, the primary waves that produce the most realistic jet-like structures are zonally-propagating intra-annual waves with periods between 60 and 130 days and wavelengths between 200 and 300 km. The NLTI mechanism is a first step towards the generation of a permanent jet-structured circulation, and is discussed in the context of turbulent cascade theories.

scholarly journals Role of Eddy Forcing in the Dynamics of Multiple Zonal Jets in a Model of the North Atlantic

2009 ◽  
Vol 39 (6) ◽  
pp. 1361-1379 ◽  
Author(s):  
Igor Kamenkovich ◽  
Pavel Berloff ◽  
Joseph Pedlosky
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Potential Vorticity ◽  
Equation Model ◽  
Vertical Diffusion ◽  
Zonal Jets ◽  
The North ◽  
The North Atlantic ◽  
Geostrophic Turbulence

Abstract Multiple zonal jets are observed in satellite data–based estimates of oceanic velocities, float measurements, and high-resolution numerical simulations of the ocean circulation. This study makes a step toward understanding the dynamics of these jets in the real ocean by analyzing the vertical structure and dynamical balances within multiple zonal jets simulated in an eddy-resolving primitive equation model of the North Atlantic. In particular, the authors focus on the role of eddy flux convergences (“eddy forcing”) in supporting the buoyancy and relative/potential vorticity (PV) anomalies associated with the jets. The results suggest a central role of baroclinic eddies in the barotropic and baroclinic dynamics of the jets, and significant differences in the effects of eddy forcing between the subtropical and subpolar gyres. Additionally, diabatic potential vorticity sources and sinks, associated with vertical diffusion, are shown to play an important role in supporting the potential vorticity anomalies. The resulting potential vorticity profile does not resemble a “PV staircase”—a distinct meridional structure observed in some idealized studies of geostrophic turbulence.

Topographic Control of Basin and Channel Flows: The Role of Bottom Pressure Torques and Friction

2006 ◽  
Vol 36 (9) ◽  
pp. 1786-1805 ◽  
Author(s):  
Laura Jackson ◽  
Chris W. Hughes ◽  
Richard G. Williams
Keyword(s):  
Western Boundary ◽  
Bottom Pressure ◽  
Boundary Currents ◽  
Zonal Jets ◽  
Subtropical Jet ◽  
Flow Through ◽  
Topographic Barriers ◽  
Barotropic Vorticity ◽  
Western Wall

Abstract The topographical control of western boundary currents within a basin and zonal jets in a channel is investigated in terms of the potential vorticity (PV) and barotropic vorticity (BV: the curl of the depth-integrated velocity) budgets using isopycnic, adiabatic wind–driven experiments. Along the western boundary, the wind-driven transport is returned across latitude lines by the bottom pressure torque, while friction is only important in altering the PV within an isopycnic layer and in allowing a closed circulation. These contrasting balances constrain the geometry of the flow through integral relationships for the BV and PV. For both homogenous and stratified basins with sloping sidewalls, the northward subtropical jet separates from the western wall and has opposing frictional torques on either side of the jet, which cancel in a zonal integral for BV but alter the PV within a layer streamline. In a channel with partial topographic barriers, the bottom pressure torque is again important in returning wind-driven flows along western boundaries and in transferring BV from neighboring wind-driven gyres into a zonal jet. The depth-integrated flow steered by topography controls where the bottom friction alters the PV, which can lead to different PV states being attained for separate subbasins along a channel.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management

The power of norms to sway fused group members

2018 ◽  
Vol 41 ◽  
Author(s):  
Winnifred R. Louis ◽  
Craig McGarty ◽  
Emma F. Thomas ◽  
Catherine E. Amiot ◽  
Fathali M. Moghaddam
Keyword(s):  
Evolutionary Anthropology ◽  
Normative Systems ◽  
Violent Extremism ◽  
Identity Fusion ◽  
Group Members

AbstractWhitehouse adapts insights from evolutionary anthropology to interpret extreme self-sacrifice through the concept of identity fusion. The model neglects the role of normative systems in shaping behaviors, especially in relation to violent extremism. In peaceful groups, increasing fusion will actually decrease extremism. Groups collectively appraise threats and opportunities, actively debate action options, and rarely choose violence toward self or others.

Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
Kevin Arceneaux
Keyword(s):  
Decision Making ◽  
Individual Differences ◽  
Cognitive Processes ◽  
Evolutionary History ◽  
Behavioral Responses ◽  
History Of ◽  
Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

The role of affect in feelings of obligation

2020 ◽  
Vol 43 ◽  
Author(s):  
Stefen Beeler-Duden ◽  
Meltem Yucel ◽  
Amrisha Vaish
Keyword(s):  
Positive Emotions ◽  
The Creation ◽  
Sense Of Obligation

Abstract Tomasello offers a compelling account of the emergence of humans’ sense of obligation. We suggest that more needs to be said about the role of affect in the creation of obligations. We also argue that positive emotions such as gratitude evolved to encourage individuals to fulfill cooperative obligations without the negative quality that Tomasello proposes is inherent in obligations.

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