scholarly journals Introduction. Progress in Earth science and climate studies

2008 ◽  
Vol 366 (1885) ◽  
pp. 4503-4508 ◽  
Author(s):  
J. Michael T Thompson
Keyword(s):  
Boreal Forests ◽  
Climate Models ◽  
Earth Science ◽  
Iron Core ◽  
Plant Soil ◽  
Introductory Paper ◽  
Circumpolar Current ◽  
Earth’S Climate ◽  
The Antarctic

In this introductory paper, I review the ‘visions of the future’ articles prepared by top young scientists for the second of the two Christmas 2008 Triennial Issues of Phil. Trans. R. Soc. A , devoted respectively to astronomy and Earth science. Topics covered in the Earth science issue include: trace gases in the atmosphere; dynamics of the Antarctic circumpolar current; a study of the boundary between the Earth's rocky mantle and its iron core; and two studies of volcanoes and their plumes. A final section devoted to ecology and climate covers: the mathematical modelling of plant–soil interactions; the effects of the boreal forests on the Earth's climate; the role of the past palaeoclimate in testing and calibrating today's numerical climate models; and the evaluation of these models including the quantification of their uncertainties.

scholarly journals Ocean and Atmosphere Storm Tracks: The Role of Eddy Vorticity Forcing

2007 ◽  
Vol 37 (9) ◽  
pp. 2267-2289 ◽  
Author(s):  
Richard G. Williams ◽  
Chris Wilson ◽  
Chris W. Hughes
Keyword(s):  
Storm Track ◽  
Heat Fluxes ◽  
Storm Tracks ◽  
Mean Flow ◽  
Ocean Eddies ◽  
Boundary Currents ◽  
The Mean ◽  
Circumpolar Current ◽  
The Antarctic

Abstract Signatures of eddy variability and vorticity forcing are diagnosed in the atmosphere and ocean from weather center reanalysis and altimetric data broadly covering the same period, 1992–2002. In the atmosphere, there are localized regions of eddy variability referred to as storm tracks. At the entrance of the storm track the eddies grow, providing a downgradient heat flux and accelerating the mean flow eastward. At the exit and downstream of the storm track, the eddies decay and instead provide a westward acceleration. In the ocean, there are similar regions of enhanced eddy variability along the extension of midlatitude boundary currents and the Antarctic Circumpolar Current. Within these regions of high eddy kinetic energy, there are more localized signals of high Eady growth rate and downgradient eddy heat fluxes. As in the atmosphere, there are localized regions in the Southern Ocean where ocean eddies provide statistically significant vorticity forcing, which acts to accelerate the mean flow eastward, provide torques to shift the jet, or decelerate the mean flow. These regions of significant eddy vorticity forcing are often associated with gaps in the topography, suggesting that the ocean jets are being locally steered by topography. The eddy forcing may also act to assist in the separation of boundary currents, although the diagnostics of this study suggest that this contribution is relatively small when compared with the advection of planetary vorticity by the time-mean flow.

scholarly journals Representation of the Antarctic Circumpolar Current in the CMIP5 climate models and future changes under warming scenarios

2012 ◽  
Vol 117 (C12) ◽  
pp. n/a-n/a ◽  
Author(s):  
A. J. S. Meijers ◽  
E. Shuckburgh ◽  
N. Bruneau ◽  
J.-B. Sallee ◽  
T. J. Bracegirdle ◽  
...  
Keyword(s):  
Antarctic Circumpolar Current ◽  
Climate Models ◽  
Cmip5 Climate Models ◽  
Circumpolar Current ◽  
The Antarctic

Mean circulation and hydrography in the Ross Sea sector, Southern Ocean: representation in numerical models

2010 ◽  
Vol 22 (5) ◽  
pp. 533-558 ◽  
Author(s):  
Graham J. Rickard ◽  
Malcolm J. Roberts ◽  
Michael J.M. Williams ◽  
Alistair Dunn ◽  
Murray H. Smith
Keyword(s):  
Southern Ocean ◽  
Antarctic Circumpolar Current ◽  
Climate Models ◽  
Ross Sea ◽  
Numerical Models ◽  
Ocean Model ◽  
Shelf Circulation ◽  
Circumpolar Current ◽  
Mean Circulation ◽  
The Antarctic

AbstractThree models were used to look at the Southern Ocean Ross Sea sector circulation and hydrography. Two were climate models of low (1°) to intermediate resolution (1/3°), and one was an operational high resolution (1/10°) ocean model. Despite model differences (including physics and forcing), mean and monthly variability aspects of off-shelf circulation are consistently represented, and could imply bathymetric constraints. Western and eastern cyclonic gyral systems separated by shallow bathymetry around 180°E redistributing water between the wider Southern Ocean and the Ross Sea are found. Some model seasonal gyral transports increase as the Antarctic Circumpolar Current transport decreases. Model flows at 900 m at the gyral eastern end compare favourably with float data. On-shelf model depth-averaged west–east flow is relatively consistent with that reconstructed from longline fishing records. These flows have components associated with isopycnal gradients in both light and dense waters. The climate models reproduce characteristic isopycnal layer inflections (‘V’s) associated with the observed Antarctic Slope Front and on-shelf deep water formation, and these models transport some 4 Sv of this bottom water northwards across the outer 1000 m shelf isobath. Overall flow complexity suggests care is needed to force regional Ross Sea models.

scholarly journals On Cabbeling and Thermobaricity in the Surface Mixed Layer

2017 ◽  
Vol 47 (7) ◽  
pp. 1775-1787 ◽  
Author(s):  
K. D. Stewart ◽  
T. W. N. Haine ◽  
A. McC. Hogg ◽  
F. Roquet
Keyword(s):  
Equation Of State ◽  
Mixed Layer ◽  
Density Field ◽  
Surface Mixed Layer ◽  
Basin Scale ◽  
Ocean Models ◽  
Circumpolar Current ◽  
Earth’S Climate ◽  
Traditional Approaches ◽  
The Antarctic

AbstractThe surface mixed layer (ML) governs atmosphere–ocean fluxes, and thereby affects Earth’s climate. Accurate representation of ML processes in ocean models remains a challenge, however. The O(100) m deep ML exhibits substantial horizontal thermohaline gradients, despite being near-homogenous vertically, making it an ideal location for processes that result from the nonlinearity of the equation of state, such as cabbeling and thermobaricity. Traditional approaches to investigate these processes focus on their roles in interior water-mass transformation and are ill suited to examine their influence on the ML. However, given the climatic significance of the ML, quantifying the extent to which cabbeling and thermobaricity influence the ML density field offers insight into improving ML representations in ocean models. A recent simplified equation of state of seawater allows the local effects of cabbeling and thermobaric processes in the ML to be expressed analytically as functions of the local temperature gradient and ML depth. These simplified expressions are used to estimate the extent to which cabbeling and thermobaricity contribute to local ML density differences. These estimates compare well with values calculated directly using the complete nonlinear equation of state. Cabbeling and thermobaricity predominantly influence the ML density field poleward of 30°. Mixed layer thermobaricity is basin-scale and winter intensified, while ML cabbeling is perennial and localized to intense, zonally coherent regions associated with strong temperature fronts, such as the Antarctic Circumpolar Current and the Kuroshio and Gulf Stream Extensions. For latitudes between 40° and 50° in both hemispheres, the zonally averaged effects of ML cabbeling and ML thermobaricity can contribute on the order of 10% of the local ML density difference.

The atmospheric ocean: eddies and jets in the Antarctic Circumpolar Current

2008 ◽  
Vol 366 (1885) ◽  
pp. 4529-4541 ◽  
Author(s):  
Andrew F Thompson
Keyword(s):  
Antarctic Circumpolar Current ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Ocean Eddies ◽  
Oceanic Current ◽  
The Earth ◽  
Primary Means ◽  
Circumpolar Current ◽  
The Antarctic

Although the Antarctic Circumpolar Current (ACC) is the longest and the strongest oceanic current on the Earth and is the primary means of inter-basin exchange, it remains one of the most poorly represented components of global climate models. Accurately describing the circulation of the ACC is made difficult owing to the prominent role that mesoscale eddies and jets, oceanic equivalents of atmospheric storms and storm tracks, have in setting the density structure and transport properties of the current. The successes and limitations of different representations of eddy processes in models of the ACC are considered, with particular attention given to how the circulation responds to changes in wind forcing. The dynamics of energetic eddies and topographically steered jets may both temper and enhance the sensitivity of different aspects of the ACC's circulation to changes in climate.

scholarly journals Observations of the ophiuroids from the West Antarctic sector of the Southern Ocean

2012 ◽  
Vol 25 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Chester J. Sands ◽  
Huw J. Griffiths ◽  
Rachel V. Downey ◽  
David K.A. Barnes ◽  
Katrin Linse ◽  
...  
Keyword(s):  
Regional Differences ◽  
The West ◽  
Amundsen Sea ◽  
West Antarctic ◽  
Dominant Component ◽  
Antarctic Continental Shelf ◽  
Scotia Arc ◽  
Circumpolar Current ◽  
The Antarctic

AbstractOphiuroids are a conspicuous and often dominant component of the Antarctic continental shelf benthos. Here we report on the ophiuroids collected from the Burdwood Bank, off the Patagonian Shelf, through the shallow water areas of the Scotia Arc, down the west Antarctic Peninsula and as far south as Pine Island Bay in the eastern Amundsen Sea. This preliminary and primarily pattern based study identifies some regional differences in assemblages and highlights the role of the Antarctic Circumpolar Current as a barrier, as well as a facilitator, to dispersal. In order to effectively compare between studies we highlight the need for accurate, expert taxonomic identification of specimens.

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