scholarly journals AMS 14C Study of Transient Events and of the Ventilation Rate of the Pacific Intermediate Water During the Last Deglaciation

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 493-502 ◽  
Author(s):  
Jean-Claude Duplessy ◽  
Maurice Arnold ◽  
Edouard Bard ◽  
Anne Juillet-Leclerc ◽  
Nejib Kallel ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Benthic Foraminifera ◽  
North Pacific Ocean ◽  
Ice Age ◽  
Intermediate Water ◽  
Last Deglaciation ◽  
Cold Event ◽  
Deep Sea Sediment ◽  
The North ◽  
The Pacific

14C analysis of monospecific samples of planktonic and benthic foraminifera were performed in deep-sea sediment cores from the Atlantic and Pacific Oceans by Accelerator Mass Spectrometry (AMS). These measurements demonstrate that the Younger Dryas cold event, first described in the north Atlantic, is also present at the same time in the north Pacific Ocean. The comparison of the 14C ages of planktonic and benthic foraminifera from the same sediment level in two Pacific cores shows that the ventilation time of the Pacific Ocean was greater than today during the last ice age, but significantly less than today during the deglaciation.

scholarly journals Wind- versus Eddy-Forced Regional Sea Level Trends and Variability in the North Pacific Ocean

2015 ◽  
Vol 28 (4) ◽  
pp. 1561-1577 ◽  
Author(s):  
Bo Qiu ◽  
Shuiming Chen ◽  
Lixin Wu ◽  
Shinichiro Kida
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Momentum Flux ◽  
North Pacific Ocean ◽  
Kuroshio Extension ◽  
The Past ◽  
The North ◽  
The Pacific ◽  
Regional Sea Level ◽  
Sea Level Trend

Abstract Regional sea level trend and variability in the Pacific Ocean have often been considered to be induced by low-frequency surface wind changes. This study demonstrates that significant sea level trend and variability can also be generated by eddy momentum flux forcing due to time-varying instability of the background oceanic circulation. Compared to the broad gyre-scale wind-forced variability, the eddy-forced sea level changes tend to have subgyre scales and, in the North Pacific Ocean, they are largely confined to the Kuroshio Extension region (30°–40°N, 140°–175°E) and the Subtropical Countercurrent (STCC) region (18°–28°N, 130°–175°E). Using a two-layer primitive equation model driven by the ECMWF wind stress data and the eddy momentum fluxes specified by the AVISO sea surface height anomaly data, the relative importance of the wind- and eddy-forced regional sea level trends in the past two decades is quantified. It is found that the increasing (decreasing) trend south (north) of the Kuroshio Extension is due to strengthening of the regional eddy forcing over the past two decades. On the other hand, the decreasing (increasing) sea level trend south (north) of the STCC is caused by the decadal weakening of the regional eddy momentum flux forcing. These decadal eddy momentum flux changes are caused by the background Kuroshio Extension and STCC changes in connection with the Pacific decadal oscillation (PDO) wind pattern shifting from a positive to a negative phase over the past two decades.

A modelling perspective of North Pacific Intermediate water in the future

2020 ◽  
Author(s):  
Xun Gong ◽  
Lars Ackermann ◽  
Gerrit Lohmann
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
Carbon Sink ◽  
North Pacific Ocean ◽  
Intermediate Water ◽  
North Pacific Intermediate Water ◽  
The North ◽  
The Future ◽  
Near Future ◽  
The North Pacific

<p>North Pacific Intermediate water (NPIW) is a dominant water mass controlling ~400-1200m depth North Pacific Ocean, characterized by its low salinities and relatively lower temperatures. In the modern climate, the interplay between NPIW-related physical and biogeochemical processes among seasons determines annual-mean budget and efficiency of carbon sink into the North Pacific Ocean. Thus, to understand the NPIW physics is key to project roles of the North Pacific Ocean in changing Earth climate and carbon systems in the future. In this study, we provide a modelling view of the NPIW history since Yr 1850 (historical experiment) and its projection to near future (IPCC-defined RCP 4.2 and 8.5 experiments until Yr 2100), using new-generation Alfred Wegener Institute Earth System Model (AWI-ESM). Our results suggest an important role of regional hydroclimate feedback over the NW Pacific and Sea of Okhotsk in determining the NPIW from recent past to near future.</p>

Biology of the Pacific Pomfret (Brama japonica) in the North Pacific Ocean

1993 ◽  
Vol 50 (12) ◽  
pp. 2608-2625 ◽  
Author(s):  
William G. Pearcy ◽  
Joseph P. Fisher ◽  
Mary M. Yoklavich
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Gulf Of Alaska ◽  
Small Fish ◽  
Large Fish ◽  
The North ◽  
The Pacific ◽  
Subarctic Current ◽  
The North Pacific

Abundances of Pacific pomfret (Brama japonica), an epipelagic fish of the North Pacific Ocean, were estimated from gillnet catches during the summers of 1978–1989. Two size modes were common: small pomfret <1 yr old, and large fish ages 1–6. Large and small fish moved northward as temperatures increased, but large fish migrated farther north, often into the cool, low-salinity waters of the Central Subarctic Pacific. Lengths of small fish were positively correlated with latitude and negatively correlated with summer surface temperature. Interannual variations in the latitude of catches correlated with surface temperatures. Large catches were made in the eastern Gulf of Alaska (51–55°N) but modes of small pomfret were absent here, and large fish were rare at these latitudes farther to the west. Pomfret grow rapidly during their first two years of life. They are pectoral fin swimmers that swim continuously. They prey largely on gonatid squids in the region of the Subarctic Current in the Gulf of Alaska during summer. No evidence was found for aggregations on a scale ≤1 km. Differences in the incidence of tapeworm, spawning seasons, and size distributions suggest the possibility of discrete populations in the North Pacific Ocean.

scholarly journals Pulses of enhanced North Pacific Intermediate Water ventilation from the Okhotsk Sea and Bering Sea during the last deglaciation

2013 ◽  
Vol 9 (6) ◽  
pp. 6221-6253 ◽  
Author(s):  
L. Max ◽  
L. Lembke-Jene ◽  
J.-R. Riethdorf ◽  
R. Tiedemann ◽  
D. Nürnberg ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Deep Water ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Northwest Pacific ◽  
Intermediate Water ◽  
Okhotsk Sea ◽  
Last Deglaciation ◽  
North Pacific Intermediate Water ◽  
The Last Deglaciation

Abstract. Under modern conditions only North Pacific Intermediate Water is formed in the Northwest Pacific Ocean. This situation might have changed in the past. Recent studies with General Circulation Models indicate a switch to deep-water formation in the Northwest Pacific during Heinrich Stadial 1 (17.5–15.0 kyr) of the last glacial termination. Reconstructions of past ventilation changes based on paleoceanographic proxy records are still insufficient to test whether a deglacial mode of deep-water formation in the North Pacific Ocean existed. Here we present deglacial ventilation records based on radiocarbon-derived ventilation ages in combination with epibenthic stable carbon isotopes from the Northwest Pacific including the Okhotsk Sea and Bering Sea, the two potential source regions for past North Pacific ventilation changes. Evidence for most rigorous ventilation of the mid-depth North Pacific occurred during Heinrich Stadial 1 and the Younger Dryas, simultaneous to significant reductions in Atlantic Meridional Overturning Circulation. Concurrent changes in δ13C and ventilation ages point to the Okhotsk Sea as driver of millennial-scale changes in North Pacific Intermediate Water ventilation during the last deglaciation. Our records additionally indicate that changes in the δ13C intermediate water (700–1750 m water depth) signature and radiocarbon-derived ventilation ages are in antiphase to those of the deep North Pacific Ocean (>2100 m water depth) during the last glacial termination. Thus, intermediate and deep-water masses of the Northwest Pacific have a differing ventilation history during the last deglaciation.

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