- Settore: 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 ...
(1879-1967) A Harvard-trained zoologist who first went to see on an expedition to the Maldive Islands with Alexander Agassiz in 1901. He later participated in the Eastern Tropical Pacific Expedition also organized by Agassiz. He first led an expedition in 1908 when he took to Grampus to Gulf Stream waters to collect various faunal samples. After four years of writing and publishing the results from these expeditions, the desk-bound Bigelow embarked on a groundbreaking series of research cruises in the Gulf of Maine in 1912. He spent the next 15 years, interrupted briefly by service as a navigation officer on an army transport, doing repeated studies of the Gulf of Maine in the manner pioneered by the ICES in Europe twenty years before. He studied the fish, plankton and hydrography of the Gulf, repeatedly taking many measurements over the years including temperatures, water samples, water color and transparency, currents (using an Ekman current meter), salinity (using the ICES method of titration and their Standard Water), quantitative and regular plankton hauls, and dredging and trawling. In later years he would release drift bottles to deduce the overall Lagrangian circulation pattern in the Gulf.
Bigelow was an American pioneer in that he was the first to apply the ICES methods of repeated measurements over many years to American waters. The results of the Gulf of Maine studies were published in separate monographs for the fish (1915), plankton (1926), and physical oceanography (Bigelow (1927)). Bigelow also published an autobiography (Bigelow (1964)) and an economic overview of oceanography (Bigelow (1931).
Industry:Earth science
That part or zone of a beach profile that extends landward from the sloping foreshore to a point of either vegetation development or a change of physiography, e.g. a sea cliff or a dune field.
Industry:Earth science
A NOAA ERL project undertaken to provide a quantitative understanding of the circulation over the Beaufort Sea Shelf and of its atmospheric and ocean forcing. Major emphasis was placed on providing extensive synoptic oceanographic and meteorological coverage of the Beaufort Sea during 1986-88.
Industry:Earth science
A western boundary current that forms the western limb of the subtropical gyre in the South Atlantic Ocean. This current is conspicuously weak as compared with other western boundary currents since only about 4 Sv of the water from the northern limb of the gyre, i.e. the South Equatorial Current (SEC), turns south, with the rest turning north to feed the North Brazil Current (NBC). The BC is not only comparatively weak but also much weaker than might be expected from observed wind fields, more about which later.
The portion of the SEC that feeds the BC turns south at about 10-15° S. The incipient BC is shallow and flows closely confined to the continental shelf, with direct current measurements at 23° S showing that nearly half of its transport of 11 Sv was inshore of the the 200 m isobath. There also seems to be a semi-permanent offshore meander near 22-23° S that may be related to local upwelling. South of 24° S the BC flow intensifies at a rate of about 5% per 100 km, with the intensification apparently linked to a recirculation cell south of about 30° S (although there is some evidence for an more extensive recirculation cell extending from 20 to 40° S).
Geostrophic transport estimates for the southern BC based on shallow or intermediate zero flow levels (1300-1600 m) have ranged from 18-22 Sv at 33-38° S. Evidence for much deeper flow (from the examination of water mass characteristics) has led to estimates ranging from 70-76 Sv at 37-38° S with a zero flow level at 3000 m. The latter estimates are at latitudes very close to where the BC separates from the coast and thus may be considered as estimates of the maximum BC flow.
The BC separates from the continental shelf between 33 and 38° S with the average being near 36° S. There is some evidence for a seasonal variation in the latitude of this point, with it being generally farther north in the (local) winter than in summer. After it separates from the boundary, it continues to flow in a general southward direction together with the return flow from the Falkland Current, with the southern limit to the warm water it bounds fluctuating between 38-46° S on time scales of about two months. After the flow reaches it maximal southern extent it turns back towards the north (as what is sometimes called the Brazil Current Front) and appears to close back on its source flow near 42° S. The north-south excursions of its southern limit result in eddies averaging about 150 km in diameter being shed at a rate of about one per week.
It was first proposed by Stommel that the reason the BC is weaker than expected from observed wind fields is because of an opposing effect of the thermohaline circulation. The formation of North Atlantic Deep Water requires a net transfer of thermocline water from the South Atlantic to the North as well as net northward fluxes of intermediate and bottom waters. This leads to the situation where the surface circulation of the South Atlantic subtropical gyre is not a closed system because the majority of the SEC flow turns north and crosses the equator due to the demands of the thermohaline circulation.
Industry:Earth science
The middle of three layers into which the bottom 1000 m of the ocean are sometimes divided, with the other two being the BNL and the BEL. The thickness of the BML typically ranges from 20-80 m, although values between 10-150 m have been observed. The particle concentration within the BML is usually homogeneously mixed, although occasional episodes of local resuspension by strong bottom flows can change this.
Industry:Earth science
The local name given to tropical cyclones in the Phillipines, especially those occurring from July to November.
Industry:Earth science
An instrumented and unmanned mooring designed to acoustically measure the size and abundance of marine life populations, collect the supporting data that characterizes the marine environment, and automatically transmit the data to shore stations for analysis. The BITS system was developed by Tracor and the University of Southern California. It employs a bi-frequency acoustic projector which operates at 165 kHz and 1. 1 MHz, with backscattered acoustic signals received by the sensors transmitted via VHF packet telemetry to shore stations.
Industry:Earth science
A marginal sea located off Antarctica from approximately 70 to 100° W northwards to the Antarctic Circle. It is located between Thurston Island to the west and the Antarctic Peninsula to the east and was named for the Russian admiral Baron Fabian Gottlieb von Bellingshausen who led an expedition to Antarctic waters at the behest of Alexander I in 1819. He is considered the first to have actually discovered the continent of Antarctic, those preceding him not having seen it because of ice and low visibility. The geographic features include Ronne and Marguerite Bay as well as Peter I, Charcot and Alexander I Islands.
Industry:Earth science
The lowest of three layers into which the bottom 1000 m of the ocean are sometimes divided, with the other two being the BNL and the BML. The height of the turbulent BEL depends on the near-bottom current speed and varies in time.
Industry:Earth science
A research project developed under the auspices of IASC for studying the impacts of global change in the Barents region, which includes the Barents Sea and the northernmost parts of Sweden, Finland, Norway and European Russia. The main emphasis is on the Barents Sea and fisheries, and on terrestrial ecosystems, forestry and reindeer herding.
Industry:Earth science
