Ice shelf-ocean interactions in a general circulation model : melt-rate modulation due to mean flow and tidal currents

This paper describes the near-surface transport properties and Lagrangian statistics in the Adriatic semi-enclosed basin using synthetic drifters. Lagrangian transport models were used to simulate synthetic trajectories from the mean flow fields obtained by the Massachusetts Institute of Technology general circulation model (MITgcm), implemented in the Adriatic from October 2006 until December 2008. In particular, the surface circulation properties in two contrasting years (2007 had a mild winter and cold fall, while 2008 had a normal winter and hot summer) are compared here. In addition, the Lagrangian statistics for the entire Adriatic Basin after removing the Eulerian mean circulation for numerical particles were calculated. The results indicate that the numerical particles were slower in this simulation when compared with the real drifters. This is because of the reduced energetic flow field generated by the MIT general circulation model during the selected years. The numerical results showed that the balanced effects of the wind-driven recirculation in the northernmost area(which would be a sea response to the Bora wind field) and the Po River discharge cause the residence times to be similar during the two selected years (182 and 185 days in 2007 and 2008, respectively). Furthermore, the mean angular momentum, diffusivity, and Lagrangian velocity covariance values are smaller than in the real drifter observations, while the maximum Lagrangian integral time scale is the same.

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Wave–Mean Flow Interactions in a General Circulation Model of the Troposphere and Stratosphere

Journal of the Atmospheric Sciences ◽

10.1175/1520-0469(1986)043<1711:wfiiag>2.0.co;2 ◽

1986 ◽

Vol 43 (16) ◽

pp. 1711-1725 ◽

Cited By ~ 33

Author(s):

Byron A. Boville

Keyword(s):

General Circulation Model ◽

General Circulation ◽

Circulation Model ◽

Mean Flow ◽

Flow Interactions

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Prognostic Residual Mean Flow in an Ocean General Circulation Model and its Relation to Prognostic Eulerian Mean Flow

Journal of Physical Oceanography ◽

10.1175/jpo-d-15-0024.1 ◽

2015 ◽

Vol 45 (9) ◽

pp. 2247-2260 ◽

Cited By ~ 5

Author(s):

Juan A. Saenz ◽

Qingshan Chen ◽

Todd Ringler

Keyword(s):

General Circulation Model ◽

Ocean Circulation ◽

General Circulation ◽

Mesoscale Eddy ◽

Circulation Model ◽

Ocean General Circulation Model ◽

Mean Flow ◽

Starting Point ◽

Horizontal Momentum ◽

Ocean General Circulation

AbstractRecent work has shown that taking the thickness-weighted average (TWA) of the Boussinesq equations in buoyancy coordinates results in exact equations governing the prognostic residual mean flow where eddy–mean flow interactions appear in the horizontal momentum equations as the divergence of the Eliassen–Palm flux tensor (EPFT). It has been proposed that, given the mathematical tractability of the TWA equations, the physical interpretation of the EPFT, and its relation to potential vorticity fluxes, the TWA is an appropriate framework for modeling ocean circulation with parameterized eddies. The authors test the feasibility of this proposition and investigate the connections between the TWA framework and the conventional framework used in models, where Eulerian mean flow prognostic variables are solved for. Using the TWA framework as a starting point, this study explores the well-known connections between vertical transfer of horizontal momentum by eddy form drag and eddy overturning by the bolus velocity, used by Greatbatch and Lamb and Gent and McWilliams to parameterize eddies. After implementing the TWA framework in an ocean general circulation model, the analysis is verified by comparing the flows in an idealized Southern Ocean configuration simulated using the TWA and conventional frameworks with the same mesoscale eddy parameterization.

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Effects of the Mean Flow on Martian Transient Eddy Activity: Studies with an Idealized General Circulation Model

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-18-0247.1 ◽

2019 ◽

Vol 76 (8) ◽

pp. 2375-2397

Author(s):

Todd A. Mooring ◽

Isaac M. Held ◽

R. John Wilson

Keyword(s):

General Circulation Model ◽

Spatial Patterns ◽

General Circulation ◽

Circulation Model ◽

Transient Eddy ◽

Mean Flow ◽

Eddy Activity ◽

Idealized Model ◽

Zonal Wavenumber ◽

The Mean

Abstract The extent to which the eddy statistics of the Martian atmosphere can be inferred from the mean state and highly simplified assumptions about diabatic and frictional processes is investigated using an idealized general circulation model (GCM) with Newtonian relaxation thermal forcing. An iterative technique, adapted from previous terrestrial studies, is used to generate radiative equilibrium temperatures such that the three-dimensional time-mean temperature fields of the idealized model match means computed from the Mars Analysis Correction Data Assimilation (MACDA). Focusing on a period of strong Northern Hemisphere eddy activity prior to winter solstice, it is found that the idealized model reproduces some key features of the spatial patterns of the MACDA eddy temperature variance and kinetic energy fields. The idealized model can also simulate aspects of MACDA’s seasonal cycle of spatial patterns of low-level eddy meridional wind and temperature variances. The most notable weakness of the model is its eddy amplitudes—both their absolute values and seasonal variations are quite unrealistic, for reasons unclear. The idealized model was also run with a mean flow based on output from the Geophysical Fluid Dynamics Laboratory (GFDL) full-physics Mars GCM. The idealized model captures the difference in mean flows between MACDA and the GFDL Mars GCM and reproduces a bias in the more complex model’s eddy zonal wavenumber distribution. This implies that the mean flow is an important influence on transient eddy wavenumbers and that improving the GFDL Mars GCM’s mean flow would make its eddy scales more realistic.

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