scholarly journals Glider observations of the North Equatorial Current in the western tropical Pacific

2015 ◽  
Vol 120 (5) ◽  
pp. 3586-3605 ◽  
Author(s):  
Martha C. Schönau ◽  
Daniel L. Rudnick
Keyword(s):  
Tropical Pacific ◽  
North Equatorial Current ◽  
Western Tropical Pacific ◽  
The North ◽  
Equatorial Current

Intraseasonal Variability of the Surface Zonal Currents in the Western Tropical Pacific Ocean: Characteristics and Mechanisms

2016 ◽  
Vol 46 (12) ◽  
pp. 3639-3660 ◽  
Author(s):  
Fan Wang ◽  
Yuanlong Li ◽  
Jianing Wang
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
General Circulation ◽  
Intraseasonal Variability ◽  
Circulation Model ◽  
Tropical Pacific ◽  
North Equatorial Current ◽  
Tropical Pacific Ocean ◽  
Western Tropical Pacific ◽  
Equatorial Current

AbstractThe surface circulation of the tropical Pacific Ocean is characterized by alternating zonal currents, such as the North Equatorial Current (NEC), North Equatorial Countercurrent (NECC), South Equatorial Current (SEC), and South Equatorial Countercurrent (SECC). In situ measurements of subsurface moorings and satellite observations reveal pronounced intraseasonal variability (ISV; 20–90 days) of these zonal currents in the western tropical Pacific Ocean (WTPO). The amplitude of ISV is the largest within the equatorial band exceeding 20 cm s−1 and decreases to ~10 cm s−1 in the NECC band and further to 4–8 cm s−1 in the NEC and SECC. The ISV power generally increases from high frequencies to low frequencies and exhibits a peak at 50–60 days in the NECC, SEC, and SECC. These variations are faithfully reproduced by an ocean general circulation model (OGCM) forced by satellite winds, and parallel model experiments are performed to gain insights into the underlying mechanisms. It is found that large-scale ISV (>500 km) is primarily caused by atmospheric intraseasonal oscillations (ISOs), such as the Madden–Julian oscillation (MJO), through wind stress forcing. These signals are confined within 10°S–8°N, mainly as baroclinic ocean wave responses to ISO winds. For scales shorter than 200 km, ISV is dominated by ocean internal variabilities with mesoscale structures. They arise from the baroclinic and barotropic instabilities associated with the vertical and horizontal shears of the upper-ocean circulation. The ISV exhibits evident seasonal variation, with larger (smaller) amplitude in boreal winter (summer) in the SEC and SECC.

Seasonal variability of the bifurcation of the North Equatorial Current

2013 ◽  
Vol 25 (4) ◽  
pp. 550-555 ◽  
Author(s):  
Qiang-chang Ju ◽  
Song Jiang ◽  
Ji-wei Tian ◽  
Ling-hai Kong ◽  
Guo-xi Ni
Keyword(s):  
Seasonal Variability ◽  
North Equatorial Current ◽  
The North ◽  
Equatorial Current

scholarly journals Shallow-Water Foraminifera and Other Microscopic Biota of Clipperton Island, Tropical Eastern Pacific

2019 ◽  
Author(s):  
Mary L McGann ◽  
Robert W. Schmieder ◽  
Louis-Philippe Loncke
Keyword(s):  
Shallow Water ◽  
Geographic Location ◽  
Oceanic Islands ◽  
Tropical Pacific ◽  
Eastern Pacific ◽  
North Equatorial Current ◽  
Tropical Eastern Pacific ◽  
Foraminiferal Assemblage ◽  
Island Endemic ◽  
The North

<p></p><p>The recent foraminiferal fauna and associated microbiota of Clipperton Island (10.2833°N, 109.2167°W) were investigated at 20 sites collected in the intertidal zone around the perimeter of the island and from the edge of the inner brackish-water lagoon. Due to the island’s geographic location in a low productivity zone, a lack of variable habitats on and surrounding the island, and heavy surf that pounds the exposed land, a depauperate fauna was recovered although mixed biogeographic affinities are represented. The shallow-water foraminiferal assemblage has no endemics but primarily tropical Indo-Pacific and eastern Pacific (Panamic) affinities, as well as one species of Caribbean affinity. The most abundant taxa are <i>Sorites</i> spp. and <i>Quinqueloculina</i> spp. Noticeably absent are any species of <i>Amphistegina, </i>despite the fact that they are considered ubiquitous in the tropical Pacific. The molluscan fauna has Clipperton Island endemics, a tropical Pacific/Inter-Island endemic, and tropical eastern Pacific oceanic islands/Panamic Molluscan affinities. The ostracods included endemics found restricted to Clipperton Island lagoon, as well as Indo-Pacific and Panamic Province species. The foraminifera, mollusks, and ostracods are thought to disperse to Clipperton Island by way of the North Equatorial Countercurrent and North Equatorial Current, suggesting that the island is indeed a stepping stone for migration both east and west across the Eastern Pacific Barrier.</p><br><p></p>

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
East Asia ◽  
Early Life History ◽  
Kuroshio Current ◽  
Japanese Eel ◽  
North Equatorial Current ◽  
Mariana Islands ◽  
The North ◽  
Management Plans ◽  
Equatorial Current ◽  
Glass Eels

Abstract.—The Japanese eel, Anguilla japonica, is an important food fish in East Asia, and catches of glass eels and of eels in freshwater appear to have declined dramatically in recent decades, causing increasing concern for the health of wild stocks. During that time, research efforts to understand its biology have progressed considerably. The spawning area was successfully outlined to the west of the Mariana Islands in 1991, and other research suggests that their recruitment success may be related to El Niño events, which appear to affect the transfer of leptocephali from the north equatorial current into the Kuroshio Current. Otolith microstructure and microchemistry studies have revealed various aspects of their early life history that relate to their oceanic larval migration. The discovery of sea eels that live in marine habitats without entering freshwater may change the common understanding of freshwater eel ecology and affect management plans. Most genetic studies suggest that the Japanese eel is composed of a single panmictic population throughout East Asia. Therefore, international management is needed among the countries of China, Taiwan, Korea, and Japan, where glass eels recruit from a common stock and are used extensively for aquaculture.

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