Recent Bottom Water Warming in the Pacific Ocean*

2007 ◽  
Vol 20 (21) ◽  
pp. 5365-5375 ◽  
Author(s):  
Gregory C. Johnson ◽  
Sabine Mecking ◽  
Bernadette M. Sloyan ◽  
Susan E. Wijffels
Keyword(s):  
Pacific Ocean ◽  
Bottom Water ◽  
World Ocean ◽  
Heat Content ◽  
Temperature Changes ◽  
The North ◽  
Time Period ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Pacific

Abstract Decadal changes of abyssal temperature in the Pacific Ocean are analyzed using high-quality, full-depth hydrographic sections, each occupied at least twice between 1984 and 2006. The deep warming found over this time period agrees with previous analyses. The analysis presented here suggests it may have occurred after 1991, at least in the North Pacific. Mean temperature changes for the three zonal and three meridional hydrographic sections analyzed here exhibit abyssal warming often significantly different from zero at 95% confidence limits for this time period. Warming rates are generally larger to the south, and smaller to the north. This pattern is consistent with changes being attenuated with distance from the source of bottom water for the Pacific Ocean, which enters the main deep basins of this ocean southeast of New Zealand. Rough estimates of the change in ocean heat content suggest that the abyssal warming may amount to a significant fraction of upper World Ocean heat gain over the past few decades.

Numerical modeling of the consequences of "marine heatwaves" in the North Pacific for the Arctic Ocean

2021 ◽  
Author(s):  
Elena Golubeva ◽  
Gennady Platov ◽  
Marina Kraineva
Keyword(s):  
Pacific Ocean ◽  
Chukchi Sea ◽  
Heat Content ◽  
The Arctic ◽  
Bering Strait ◽  
The North ◽  
Pacific Waters ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Pacific

<p>As a result of the analysis of the NOAA surface temperature observational data (Huang et al., 2020), the periods corresponding to "marine heatwaves" in the northeastern Pacific Ocean (2013-2019) were identified. Marine heatwaves were defined as exceeding the 90th percentile threshold. The same analysis of the temperature in the Bering Strait's immediate vicinity showed anomalously warm waters in the same years. Analysis of the pressure field, which forms the atmosphere's dynamic state and affects the water circulation system of the Bering Sea, allowed us to assume the inflow of anomalously warm Pacific waters into the Chukchi Sea. To analyze the North Pacific heatwaves' consequences for the Arctic Ocean, we carried out two numerical experiments using the regional ocean and sea ice model SibCIOM (Golubeva et al., 2018) and NCEP/NCAR atmospheric reanalysis data (Kalnay et al., 1996). The first numerical experiment was carried out to calculate hydrodynamic and ice fields from January 2000 to November 2020 (Experiment 1). On the Arctic and the Pacific Ocean boundary in the Bering Strait, we used the monthly average climatic values ​​of the transport, temperature, and salinity of waters coming from the Pacific Ocean. Experiment 2 was carried out from 2014 to November 2020. The calculated values ​​of hydrological and ice characteristics obtained in Experiment 1 were used as the initial state for this experiment. In contrast to Experiment 1,  a heat flux exceeding the average climatic values ​​was set at the Bering Strait in Experiment 2. Its assignment was provided by using temperature values ​​from observational data in the Bering Strait vicinity (Huang et al., 2020). Comparison of monthly average hydrological and ice fields obtained in two numerical experiments and analysis of numerical results showed that an increase in the temperature of the Pacific waters entering the Arctic shelf through the Bering Strait leads to an increase in the heat content of the Chukchi Sea waters, heat transfer by currents in the surface and subsurface layers, a gradual increase in the heat content of the Beaufort Sea, and the reduction of Arctic ice cover. The increase in heat content in Experiment 2 for the Beaufort Sea was obtained in both the upper 50-meter and 250-meter layers.</p><p>The research is supported by the Russian Science Foundation, grant №. 19-17-00154.</p>

scholarly journals WOCE AMS Radiocarbon I: Pacific Ocean Results (P6, P16 and P17)

Radiocarbon ◽  
1996 ◽  
Vol 38 (3) ◽  
pp. 425-518 ◽  
Author(s):  
Robert M. Key ◽  
Paul D. Quay ◽  
Glenn A. Jones ◽  
A. P. McNichol ◽  
K. F. Von Reden ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
World Ocean ◽  
Depth Range ◽  
Near Surface ◽  
The North ◽  
The Pacific ◽  
World Ocean Circulation Experiment ◽  
The Pacific Ocean ◽  
Similar Density

AMS radiocarbon results from the World Ocean Circulation Experiment in the Pacific Ocean show dramatic changes in the inventory and distribution of bomb-produced 14C since the time of the GEOSECS survey (8/73–6/74). Near-surface Δ14C values for the eastern portion of both the northern and southern subtropical gyres decreased by 25–50‰, with the change being greater in the north. Equatorial near-surface values have increased by ca. 25‰. Changes in the 250–750-m depth range are dramatically different between the northern and southern basins. The intermediate and mode waters of the southern basin have increased by as much as 75‰ since GEOSECS. Waters of similar density in the northern hemisphere are not exposed to the Southern Ocean circulation regime and are significantly less ventilated, showing maximum changes of ca. 50‰.

scholarly journals Decadal Changes in Bomb-Produced Radiocarbon in the Pacific Ocean from the 1990s to 2000s

Radiocarbon ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 1641-1650 ◽  
Author(s):  
Yuichiro Kumamoto ◽  
Akihiko Murata ◽  
Takeshi Kawano ◽  
Shuichi Watanabe ◽  
Masao Fukasawa
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
Dissolved Inorganic Carbon ◽  
World Ocean ◽  
Temporal Changes ◽  
Turnover Time ◽  
Subtropical Region ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean

In the 2000s, radiocarbon in dissolved inorganic carbon was measured during 7 revisit cruises along the lines of the World Ocean Circulation Experiment in the Pacific Ocean. Comparison of 14C data along these lines from the 1990s and 2000s revealed decadal changes of 14C concentration in the thermocline, most of which were due to temporal changes in the bomb-produced 14C. Vertical profiles and vertical-integrated inventories of the bomb 14C in the subarctic and equatorial regions did not change appreciably. In the southern subtropical region, 14C decreased in the upper thermocline from the surface to ∼500 m depth. In contrast, 14C increased in the lower thermocline below ∼500 m depth. The opposing directions in 14C change resulted in small temporal changes in the total inventory of bomb 14C. On the other hand, the water-column inventory significantly decreased in the northwestern subtropical region due to the 14C decrease in the upper thermocline. These decadal changes in bomb 14C indicate that the turnover time of thermocline circulation in the northwestern subtropical region is faster than that in the southern subtropical region, and imply an interbasin transport of bomb 14C from the North Pacific to other basins.

Oceanographic Regions and Assessment of Temperature Structure in the Seasonal Zone of the North Pacific Ocean

1964 ◽  
Vol 21 (5) ◽  
pp. 941-970 ◽  
Author(s):  
John P. Tully
Keyword(s):  
Pacific Ocean ◽  
North Pacific Ocean ◽  
The Arctic ◽  
Temperature Structure ◽  
Universal System ◽  
Climatic Regions ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Pacific

There are eight climatic regions from the Equator to the Arctic in the Pacific Ocean. In each region the distinct oceanographic temperature structures and their seasonal sequences are described and related to surface weather processes and transport. Procedures for observation and interpretation of data must be adapted to suit the regional models of structure and behaviour. However, a rational universal system of information presentation is feasible and is demonstrated. The concepts may be extended to other oceans.

The possible formation mechanism of the Subtropical Countercurrent in the Pacific Ocean

2020 ◽  
Author(s):  
Zhichun Zhang ◽  
huijie Xue
Keyword(s):  
Pacific Ocean ◽  
Model Simulation ◽  
North Pacific Ocean ◽  
Luzon Strait ◽  
The West ◽  
The North ◽  
Subtropical Countercurrent ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Pacific

<p>            Based on a nonlinear reduced gravity model simulation, formation cause of Subtropical Countercurrent(STCC) in the Pacific Ocean are investigated. The model reproduces well the characteristics of circulation of thermocline in the North pacific Ocean. The results suggest that the variation of the west boundary topography, especially the witdh of the luzon strait, play a key role on the formationg of STCC as well as the wind sress meridional gradient. When the witdh of the luzon strait gradually decrease, the STCC increase . the model results also reveal that the wind stress dipole curl of west ot the hawaii islands is key to the HLCC formation.</p>

scholarly journals The influence of decadal oscillations on the oxygen and nutrient trends in the Pacific Ocean

2019 ◽  
Author(s):  
Lothar Stramma ◽  
Sunke Schmidtko ◽  
Steven J. Bograd ◽  
Tsuneo Ono ◽  
Tetjana Ross ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
Tropical Pacific ◽  
Ocean Warming ◽  
The North ◽  
The Pacific ◽  
Major Mode ◽  
The Pacific Ocean ◽  
The North Pacific ◽  
The Tropical Pacific

Abstract. A strong oxygen deficient layer is located in the upper layer of the tropical Pacific Ocean and at deeper depths in the North Pacific. Processes related to climate change (upper ocean warming, reduced ventilation) are expected to change ocean oxygen and nutrient inventories. In most ocean basins, a decrease in oxygen (‘deoxygenation’) and an increase of nutrients has been observed in subsurface layers. Deoxygenation trends are not linear and there could be other influences on oxygen and nutrient trends and variability. Here oxygen and nutrient time series since 1950 in the Pacific Ocean were investigated at 50 to 300 m depth, as this layer provides critical pelagic habitat for biological communities. In addition to trends related to ocean warming the oxygen and nutrient trends show a strong influence of the Pacific Decadal Oscillation (PDO) in the tropical and the eastern Pacific, and the North Pacific Gyre Oscillation (NPGO) especially in the North Pacific. In the Oyashio Region the PDO, the NPGO, the North Pacific Index (NPI) and a 18.6 year nodal tidal cycle overlay the long-term trend. In most regions oxygen increases and nutrients decrease in the 50 to 300 m layer during the negative PDO phase, with opposite trends during the positive PDO phase. The PDO index encapsulates the major mode of surface temperature variability in the Pacific and oxygen and nutrients trends throughout the basin can be described in the context of the PDO phases. An influence of the subtropical-tropical cell in the tropical Pacific cannot be proven with the available data. El Niño and La Niña years often influence the oxygen and nutrient distribution during the event in the eastern tropical Pacific, but do not have a multi-year influence on the trends.

scholarly journals International Dimension in Colonization of the North-West of America and California at the End of the 17-18 th Centuries

2020 ◽  
Vol 13 (5) ◽  
pp. 7-30
Author(s):  
A. Y. Petrov ◽  
V. N. Kostornichenko ◽  
M. M. Koskina
Keyword(s):  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Local Population ◽  
Northwest Pacific ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
First Time ◽  
The North Pacific

The article reviews the initial period of European colonization of the North Pacific Ocean and California within the context of diplomatic relations between Russia and Spain during the late 17th and early 18th centuries. It tries to understand the policies of European powers in the American Northwest and the reasons for pursuing their colonial interests there. It analyses the history of exploration of these territories, expeditions to the northern part of the Pacific Ocean, and historical maps of this region. For the first time in Russian historiography the authors touch upon the exploration of California in the 18th century.The exploration of the North Pacific Ocean, the northwestern American coast, including certain areas of California, Alaska and the Aleutian Islands has long attracted the attention of European powers. It was a process in which government authorities and private merchant companies took part. The expansion of the Spanish Empire into California was made possible in part because of the concerns of the Madrid court about the strengthening of the Russian and British empires in the North Pacific Ocean. The Spanish documents from the archives of Madrid, Seville and Simancas – the article introduces them into research communication the first time - show the validity of the fears of the Madrid court regarding the inevitable development of Russian colonization in the region. The advance of Russia to the shores of America has economic reasons: Cossacks and merchants reached the Pacific Ocean pursuing the desire to profit from the fur trade. As the economic influence expanded, the state interests of annexing territories and bringing the local population into citizenship followed behind. The territorial advance of the Russians to the Pacific Ocean was facilitated by the ambitious, but at the same time balanced diplomacy of Peter I, which managed to ensure the expansion of the borders of the Russian Empire.Spanish consolidation in certain territories in California was aimed at a possible containment of the Russian advance. Russian-Spanish relations in the Northwest Pacific at the end of the 17th – 18th centuries contributed to the nature of the subsequent development of territories in the North Pacific Ocean.

scholarly journals Biogeochemistry of the North Atlantic during oceanic anoxic event 2: role of changes in ocean circulation and phosphorus input

2014 ◽  
Vol 11 (4) ◽  
pp. 977-993 ◽  
Author(s):  
I. Ruvalcaba Baroni ◽  
R. P. M. Topper ◽  
N. A. G. M. van Helmond ◽  
H. Brinkhuis ◽  
C. P. Slomp
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Primary Productivity ◽  
Low Oxygen ◽  
Deep Basin ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Atlantic

Abstract. The geological record provides evidence for the periodic occurrence of water column anoxia and formation of organic-rich deposits in the North Atlantic Ocean during the mid-Cretaceous (hereafter called the proto-North Atlantic). Both changes in primary productivity and oceanic circulation likely played a role in the development of the low-oxygen conditions. Several studies suggest that an increased input of phosphorus from land initiated oceanic anoxic events (OAEs). Other proposed mechanisms invoke a vigorous upwelling system and an ocean circulation pattern that acted as a trap for nutrients from the Pacific Ocean. Here, we use a detailed biogeochemical box model for the proto-North Atlantic to analyse under what conditions anoxia could have developed during OAE2 (94 Ma). The model explicitly describes the coupled water, carbon, oxygen and phosphorus cycles for the deep basin and continental shelves. In our simulations, we assume the vigorous water circulation from a recent regional ocean model study. Our model results for pre-OAE2 and OAE2 conditions are compared to sediment records of organic carbon and proxies for photic zone euxinia and bottom water redox conditions (e.g. isorenieratane, carbon/phosphorus ratios). Our results show that a strongly elevated input of phosphorus from rivers and the Pacific Ocean relative to pre-OAE2 conditions is a requirement for the widespread development of low oxygen in the proto-North Atlantic during OAE2. Moreover, anoxia in the proto-North Atlantic is shown to be greatly influenced by the oxygen concentration of Pacific bottom waters. In our model, primary productivity increased significantly upon the transition from pre-OAE2 to OAE2 conditions. Our model captures the regional trends in anoxia as deduced from observations, with euxinia spreading to the northern and eastern shelves but with the most intense euxinia occurring along the southern coast. However, anoxia in the central deep basin is difficult to achieve in the model. This suggests that the ocean circulation used in the model may be too vigorous and/or that anoxia in the proto-North Atlantic was less widespread than previously thought.

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