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Founded in 1876, Texas A&M University is a U.S. public and comprehensive university offering a wide variety of academic programs far beyond its original label of agricultural and mechanical trainings. It is one of the few institutions holding triple federal designations as a land-, sea- and ...
Descriptive of a hypothetical atmosphere or ocean in which surfaces of pressure (isobaric surfaces) and density (isentropic surfaces) coincide at all levels, as compared to baroclinic. In a state of barotropic stratification, no potential energy is available for conversion to kinetic energy.
Industry:Earth science
An ice sheet that extends over the sea and floats on the water. These range in thickness from a few hundred to over 1000 meters and are connected to land at coastal grounding lines and where they flow around islands. They calve icebergs at their seaward fronts and gain mass by flow from grounded ice sheets and glaciers and from new snow accumulation. Iceberg calving is the primary ablation process with melting providing a secondary mechanism. Ice shelves are key indicators of climate change since they respond much more rapidly than grounded ice sheets or glaciers to changes in climate. The continent of Antarctica is surrounded by ice shelves, with the largest being the Ross Ice Shelf, covering over 500,000 km<sup>2</sup>.
Industry:Earth science
A limiting form of a long Poincare wave that oscillations at the inertial frequency. In this limit the effects of gravity are negligible and the fluid particles are moving under their own inertia, whence the name.
Industry:Earth science
The third (from the top) of seven zones into which the benthos has been divided. This has also been called the inner sublittoral zone.
Industry:Earth science
Data associated with reference to measurements made at the actual location of the object or material measured, by contrast with remote sensing (i.e., from space).
Industry:Earth science
In physical oceanography, the active exchange of waters and/or water mass properties between basins. Evidence for this process is provided by the similarities in water masses in the three major oceans despite quite different water mass conversion processes in each. The three avenues for this in the world ocean are: the Bering Strait, which provides a conduit for North Pacific-North Atlantic exchange via the Arctic Ocean; passes in the Indonesian Archipelago, which connect the Indian and Pacific Oceans at low latitudes; and the Southern Ocean, in which the ACC flows through several broad passages between Antarctica and the other southern hemisphere continents. The conveyor belt paradigm was the first attempt to tie these together into a unified theory of interbasin circulation.
The most up-to-date scenario for these interbasin circulation processes starts with 14 Sv of upper and intermediate level water being converted to NADW in the North Atlantic and flowing southward across the equator to join the ACC. This loss from the Atlantic is compensated by 10 Sv of upper level entering via the Drake Passage and 4 Sv entering from the Indonesian throughflow through the Australasian Mediterranean and around Africa. The Indian Ocean receives 24 Sv of lower level cold water from the ACC, returning 14 Sv as cold water and transforming 10 Sv to upper level water. This latter 10 Sv flows south of Australia, across the South Pacific, and through the Drake Passage into the Benguela Current regime. This joins the afore mentioned Indonesian Throughflow, crosses the equator, and flow with the Gulf Stream into the North Atlantic to replace the lost NADW. The Pacific takes 20 Sv of cold water from the ACC and returns it as less cold water, with about half of it traversing the North Pacific.
This is a simplified two-layer version of a more complicated four-layer circulation scheme developed by Schmitz (1995) which includes intermediate and upper layer compensations flows as well as abyssal and deep interbasin thermohaline circulation layers. The greatest uncertainties remain in the Indian and Pacific Oceans, especially with the flows associated with vertical exchange, which in itself is perhaps the least well established feature of ocean circulation.
Industry:Earth science
A device, e.g. imaging radar, that uses two different paths for imaging and deduces information from the coherent interference between the two signals. Paths with spatial and temporal differences have been used to measure, respectively, terrain height and ocean currents.
Industry:Earth science
A class or group of equations that have been formulated in an attempt to extend the formal validity of the quasi-geostrophic equations while also avoiding the complications of the full primitive equations. The usual approaches attempt to extend the quasigeostrophic or planetary geostrophic equations. This is done by either proceeding to a higher order in an asymptotic expansion (or similar procedure) in the Rossby number (or some other small parameter) or by attempting to extend the validity of the equations at their lowest order. A disadvantage of the former approach is that it does not extend the regime of validity of the new equations beyond that of the lowest order system. The latter approach, usually less mathematically formal, attempts to include terms neglected or inaccurately approximated in the original equations which restrict their range of applicability. These include terms involving large variations in depth, Coriolis parameter, and the advection of relative vorticity. The ultimate goal is to develop a set of equations valid for both planetary and synoptic scales.
Industry:Earth science
Internal waves somehow excited at or near tidal periods. It is generally accepted that these are generated by energy scattered from surface to internal tides by bottom roughness.
Industry:Earth science
In dynamical systems theory, a system is said to be intransitive if different sets of initial conditions evolve to more than one alternative resultant state.
Industry:Earth science
