- Industri: Education
- Number of terms: 34386
- Number of blossaries: 0
- Company Profile:
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 ...
A radioactive nuclide with a half-life of 53. 3 days produced by cosmic rays (i.e. electron capture decay to <sup>7</sup>Li) that can be used as a tracer of ventilation processes occurring on a seasonal timescale. It is deposited by rainfall on the ocean surface, and homogenized within the surface mixed layer, with a fraction found to penetrate into the upper thermocline. The extent of penetration before decay depends partly on the strength of vertical mixing and advective processes. The distribution below the mixed layer at any time depends largely on the depth history of the mixed layer, i.e. Beryllium-7 found in the thermocline can be remnant or previous mixed layers formed within several half-lives of the isotope (a seasonal timescale). Thus, if the depth history of the mixed layer is known, then the mixing and advection component affecting the Beryllium-7 distribution can be found. Conversely, given an understanding of these processes, it can be used to interpret mixed layer history on a seasonal timescale.
Industry:Earth science
A program run by the Ocean Physics Laboratory at ICESS. This mooring was deployed in June 1994 about 80 km southwest of Bermuda and has provided the oceanographic community with a deep-water platform for developing, testing, calibrating, and intercomparing instruments which can obtain long-term data sets.
Industry:Earth science
A program whose principle objective was to gain a deeper understanding of the structure and dynamic functioning of the Antarctic marine ecosystem as a basis for the future management of potential living resources. BIOMASS has two major field campaigns, the First (FIBEX) and Second (SIBEX) International BIOMASS Experiments.
The goal of FIBEX was to determine how much krill is in the Antarctic. It was composed of 16 research cruises carried out between November 1980 and April 1981, and produced a synoptic picture of the distribution of krill over a large area of the southern ocean. The goal of SIBEX was to improve the understanding of the dynamics of the krill-dominated part of the Antarctic marine ecosystem. It involved two field seasons, SIBEX-1 (8 cruises, Oct. 1983 to Apr. 1984) and SIBEX-2 (10 cruises, Nov. 1984 to Apr. 1985), and produced a temporal sequence of observations focused mainly on the Bransfield Strait and Prydz Bay regions.
Industry:Earth science
One of three geomorophologically distinct types of coral reefs, the other two being fringing reefs and atolls. Barrier reefs are separated from land by a lagoon usually formed by coastal subsidence.
Industry:Earth science
A post-LGM European climate regime. This refers to the period from about 7000-6000 BC when temperatures continued to rise, e.g. the colder seasons of the year gradually became milder (although probably with some dry and frosty winters) and the summers became generally warmer than today. It was preceded by the Pre-Boreal period and followed by the Atlantic period.
Industry:Earth science
A region where the Brazil Current meets the Malvinas Current at around 38°S. This collision of subtropical and subantarctic waters produces one of the most spectacular of the oceanic fronts and complex SST fields seen in the world ocean. At the BMC, subantarctic surface waters meet subtropical thermocline water in a front that can have a gradient as strong as 8°C per km. It is frequently marked by a ribbon of warm, low salinity water of Rio de la Plata origin that has folded over the northern tip of the cyclonic trough formed by the Malvinas Current and its return to the south. A warm, low salinity cap tens of meters thick often covers the western segments of the warm subtropical water. It is derived from the continental shelf north of the Rio de la Plata.
The specific configuration of the BMC at any given time is thought to depend on the relative strengths of the baroclinic and barotropic fields of the Malvinas and Brazil Currents. Its variability occurs over time scales ranging from the intra-annual to the inter-annual, with the spatial characteristics including changes in the latitudes of separation of the western boundary currents from the continental margin, and changes in the geometry of their extensions in the offshore region. On intra-annual time scales, the variability is dominated by the periodic production of transient, cold-core eddies from the Malvinas Current and warm-core eddies from the Brazil Current. These have associated SST anomalies that can be as large as 10°C on space and time scales of 1000 km and two months, respectively.
On annual time scales the variability of the western south Atlantic is dominated by the seasonal displacements of the BMC. It is found farther north during austral winter (July-September) than during the summer. Besides the annual cycle, thought to be driven by variations in the strengths of the Malvinas and Brazil Currents, there is a semi-annual component of variability with near zero amplitude at 30°S increasing to nearly half the magnitude of the annual signal at 50°S. This is probably a response to the semi-annual cycle in zonal winds over the Southern Ocean.
Industry:Earth science
A generalization of Stokes' theorem that enables the calculation of the circulation on a rotating Earth.
Industry:Earth science
A program to study bioluminescence and optical variability in the sea.
Industry:Earth science
A series of experiments carried out in Bass Strait, Australia during the period 1975-1985. The data sets gathered results in a clearer understanding of the relationships between wave state, wind stress, and surface layer turbulence.
Industry:Earth science
A strait located between the northern tip of the Antarctica Peninsula and the South Shetland Islands. It is about 120 km wide and extends 460 km from Clarence Island in the northeast to Low Island in the southwest. It consists of three separate basins isolated from the surrounding ocean by relatively shallow sills, with local deep water formation processes resulting in different water characteristics in each of the basins. The basins deepen to the northeast, having a maximum axial depth in the west basin of 1100 m near Low Island and a maximum depth of 2700 m in the east basin south of Elephant Island. Sills shallower than 500 m almost entirely circle the strait, with the east basin having the deepest access to outside water with sills deeper than 500 m. There are no passages deeper than 500 m into either the central or west basins, and the central basin is isolated from the adjacent basins by sills of 1000 and 1100 m at its western and eastern boundaries.
Industry:Earth science
