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Ocean current

About: Ocean current is a research topic. Over the lifetime, 9266 publications have been published within this topic receiving 409710 citations. The topic is also known as: oceanic current & sea current.


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Journal ArticleDOI
TL;DR: A number of marine water and fresh water samples were examined for the relative O18O16 ratio, and the variation of this ratio was determined to a precision of ± 1% as mentioned in this paper.

3,113 citations

Journal ArticleDOI
01 May 1995
TL;DR: In this article, large-scale features of the Antarctic Circumpolar Current (ACC) were described using all historical hydrographic data available from the Southern Ocean, and the geopotential anomaly of the sea surface relative to 1000 db reveals the highly-sheared eastward flow of the ACC and the strong steering of the current by the ridge system around Antarctica.
Abstract: Large-scale features of the Antarctic Circumpolar Current (ACC) are described using all historical hydrographic data available from the Southern Ocean. The geopotential anomaly of the sea surface relative to 1000 db reveals the highly-sheared eastward flow of the ACC and the strong steering of the current by the ridge system around Antarctica. The near-surface property distributions differentiate the ACC waters from the warmer and saltier waters of the subtropical regimes. The Subtropical Front (STF), interrupted only by South America, marks the northern most extent of subantarctic waters. Distributions of properties on isopycnal surfaces show an abrupt end to the characteristic signal of the Upper Circumpolar Deep Water (UCDW), as this water mass shoals southward and is entrained into the surface mixed layer. This sharp water mass boundary nearly coincides with the southernmost circumpolar streamline passing through Drake Passage. To its south are the weakly-sheared circulations of the subpolar regime. Inspection of many hydrographic crossings of this transition reveals that the poleward edge of the UCD W signal is a reasonable definition of the southern boundary of the ACC. At Drake Passage, three deep-reaching fronts account for most of the ACC transport. Well-established indicators of the Subantarctic Front and Polar Front are traced unbroken around Antarctica. The third deep-reaching front observed to the south of the Polar Front at Drake Passage also continues with similar characteristics as a circumpolar feature. It is called here the southern ACC front. Stations from multiple synoptic transects of these circumpolar fronts are used to describe the average property structure within each ACC zone. Between the STF and the southern boundary of the ACC, the shear transport of the circumpolar current above 3000 m is at all longitudes about 100 Sv (1 Sv = 106 m3 s−) eastward.

2,513 citations

Journal ArticleDOI
TL;DR: A decade-long change in the atmospheric circula- tion throughout the troposphere revealed a deeper and eastward shifted Aleutian low pressure system in the winter half year which advected warmer and moister air along the west coast of North America and into Alaska and colder air over the north Pacific.
Abstract: Considerable evidence has emerged of a sub- stantial decade-long change in the north Pacific atmo- sphere and ocean lasting from about 1976 to 1988. Ob- served significant changes in the atmospheric circula- tion throughout the troposphere revealed a deeper and eastward shifted Aleutian low pressure system in the winter half year which advected warmer and moister air along the west coast of North America and into Alaska and colder air over the north Pacific. Conse- quently, there were increases in temperatures and sea surface temperatures (SSTs) along the west coast of North America and Alaska but decreases in SSTs over the central north Pacific, as well as changes in coastal rainfall and streamflow, and decreases in sea ice in the Bering Sea. Associated changes occurred in the surface wind stress, and, by inference, in the Sverdrup trans- port in the north Pacific Ocean. Changes in the month- ly mean flow were accompanied by a southward shift in the storm tracks and associated synoptic eddy activi- ty and in the surface ocean sensible and latent heat fluxes. In addition to the changes in the physical envi- ronment, the deeper Aleutian low increased the nu- trient supply as seen through increases in total chloro- phyll in the water column, phytoplankton and zoo- plankton. These changes, along with the altered ocean currents and temperatures, changed the migration pat- terns and increased the stock of many fish species. A north Pacific (NP) index is defined to measure the de- cadal variations, and the temporal variability of the in- dex is explored on daily, annual, interannual and de- cadal time scales. The dominant atmosphere-ocean re- lation in the north Pacific is one where atmospheric changes lead SSTs by one to two months. However, strong ties are revealed with events in the tropical Pa- cific, with changes in tropical Pacific SSTs leading SSTs in the north Pacific by three months. Changes in the storm tracks in the north Pacific help to reinforce and maintain the anomalous circulation in the upper tro-

2,282 citations

Journal ArticleDOI
TL;DR: Using the Levitus climatology, the authors showed that 2.1 TW (terawatts) is required to maintain the global abyssal density distribution against 30 Sverdrups of deep water formation.

1,958 citations

Journal ArticleDOI
22 Apr 2004-Nature
TL;DR: It is found that the meridional overturning was nearly, or completely, eliminated during the coldest deglacial interval in the North Atlantic region, beginning with the catastrophic iceberg discharge Heinrich event H1, 17,500’yr ago, and declined sharply but briefly into the Younger Dryas cold event, about 12,700 yr ago.
Abstract: The Atlantic meridional overturning circulation is widely believed to affect climate. Changes in ocean circulation have been inferred from records of the deep water chemical composition derived from sedimentary nutrient proxies1, but their impact on climate is difficult to assess because such reconstructions provide insufficient constraints on the rate of overturning2. Here we report measurements of 231Pa/230Th, a kinematic proxy for the meridional overturning circulation, in a sediment core from the subtropical North Atlantic Ocean. We find that the meridional overturning was nearly, or completely, eliminated during the coldest deglacial interval in the North Atlantic region, beginning with the catastrophic iceberg discharge Heinrich event H1, 17,500 yr ago, and declined sharply but briefly into the Younger Dryas cold event, about 12,700 yr ago. Following these cold events, the 231Pa/230Th record indicates that rapid accelerations of the meridional overturning circulation were concurrent with the two strongest regional warming events during deglaciation. These results confirm the significance of variations in the rate of the Atlantic meridional overturning circulation for abrupt climate changes.

1,875 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023205
2022284
2021300
2020293
2019310
2018308