scholarly journals Detecting an external influence on recent changes in oceanic oxygen using an optimal fingerprinting method

2012 ◽  
Vol 9 (9) ◽  
pp. 12469-12504 ◽  
Author(s):  
O. D. Andrews ◽  
N. L. Bindoff ◽  
P. R. Halloran ◽  
T. Ilyina ◽  
C. Le Quéré
Keyword(s):  
Internal Variability ◽  
Global Ocean ◽  
External Forcing ◽  
Dissolved Oxygen Concentration ◽  
The Past ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Optimal Fingerprinting ◽  
Earth System Models ◽  
Ocean Deoxygenation

Abstract. Ocean deoxygenation has been observed in all major ocean basins over the past 50 yr. Although this signal is largely consistent with oxygen changes expected from anthropogenic climate change, the contribution of external forcing to recent deoxygenation trends relative to natural internal variability is yet to be established. Here we conduct a formal optimal fingerprinting analysis to investigate if external forcing has had a detectable influence on observed dissolved oxygen concentration ([O2]) changes between ~ 1970 and ~ 1992 using simulations from two Earth System Models (MPI-ESM-LR and HadGEM2-ES). We detect a response to external forcing at a 90% confidence level and find that observed [O2] changes are inconsistent with internal variability as simulated by models. This result is robust in the global ocean for depth-averaged (1-D) zonal mean patterns of [O2] change in both models. Further analysis with the MPI-ESM-LR model shows similar positive detection results for depth-resolved (2-D) zonal mean [O2] changes globally and for the Pacific Ocean individually. Observed oxygen changes in the Atlantic Ocean are indistinguishable from natural internal variability. Simulations from both models consistently underestimate the amplitude of historical [O2] changes in response to external forcing, suggesting that model projections for future ocean deoxygenation may also be underestimated.

scholarly journals Detecting an external influence on recent changes in oceanic oxygen using an optimal fingerprinting method

2013 ◽  
Vol 10 (3) ◽  
pp. 1799-1813 ◽  
Author(s):  
O. D. Andrews ◽  
N. L. Bindoff ◽  
P. R. Halloran ◽  
T. Ilyina ◽  
C. Le Quéré
Keyword(s):  
Internal Variability ◽  
Global Ocean ◽  
External Forcing ◽  
Dissolved Oxygen Concentration ◽  
The Past ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Optimal Fingerprinting ◽  
Earth System Models ◽  
Ocean Deoxygenation

Abstract. Ocean deoxygenation has been observed in all major ocean basins over the past 50 yr. Although this signal is largely consistent with oxygen changes expected from anthropogenic climate change, the contribution of external forcing to recent deoxygenation trends relative to natural internal variability is yet to be established. Here we conduct a formal optimal fingerprinting analysis to investigate if external forcing has had a detectable influence on observed dissolved oxygen concentration ([O2]) changes between ∼1970 and ∼1992 using simulations from two Earth System Models (MPI-ESM-LR and HadGEM2-ES). We detect a response to external forcing at a 90% confidence level and find that observed [O2] changes are inconsistent with internal variability as simulated by models. This result is robust in the global ocean for depth-averaged (1-D) zonal mean patterns of [O2] change in both models. Further analysis with the MPI-ESM-LR model shows similar positive detection results for depth-resolved (2-D) zonal mean [O2] changes globally and for the Pacific Ocean individually. Observed oxygen changes in the Atlantic Ocean are indistinguishable from natural internal variability. Simulations from both models consistently underestimate the amplitude of historical [O2] changes in response to external forcing, suggesting that model projections for future ocean deoxygenation may also be underestimated.

scholarly journals Persistence of deeply sourced iron in the Pacific Ocean

2015 ◽  
Vol 112 (5) ◽  
pp. 1292-1297 ◽  
Author(s):  
Tristan J. Horner ◽  
Helen M. Williams ◽  
James R. Hein ◽  
Mak A. Saito ◽  
Kevin W. Burton ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Carbon Fixation ◽  
Global Ocean ◽  
Oceanic Circulation ◽  
Multiple Sources ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
The Past ◽  
The Pacific ◽  
The Pacific Ocean

Biological carbon fixation is limited by the supply of Fe in vast regions of the global ocean. Dissolved Fe in seawater is primarily sourced from continental mineral dust, submarine hydrothermalism, and sediment dissolution along continental margins. However, the relative contributions of these three sources to the Fe budget of the open ocean remains contentious. By exploiting the Fe stable isotopic fingerprints of these sources, it is possible to trace distinct Fe pools through marine environments, and through time using sedimentary records. We present a reconstruction of deep-sea Fe isotopic compositions from a Pacific Fe−Mn crust spanning the past 76 My. We find that there have been large and systematic changes in the Fe isotopic composition of seawater over the Cenozoic that reflect the influence of several, distinct Fe sources to the central Pacific Ocean. Given that deeply sourced Fe from hydrothermalism and marginal sediment dissolution exhibit the largest Fe isotopic variations in modern oceanic settings, the record requires that these deep Fe sources have exerted a major control over the Fe inventory of the Pacific for the past 76 My. The persistence of deeply sourced Fe in the Pacific Ocean illustrates that multiple sources contribute to the total Fe budget of the ocean and highlights the importance of oceanic circulation in determining if deeply sourced Fe is ever ventilated at the surface.

scholarly journals A very likely weakening of Pacific Walker Circulation in constrained near-future projections

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mingna Wu ◽  
Tianjun Zhou ◽  
Chao Li ◽  
Hongmei Li ◽  
Xiaolong Chen ◽  
...  
Keyword(s):  
Climate Models ◽  
Quantitative Estimation ◽  
Walker Circulation ◽  
Internal Variability ◽  
External Forcing ◽  
Interdecadal Pacific Oscillation ◽  
Ensemble Simulations ◽  
The Pacific ◽  
Near Future ◽  
Earth System Models

AbstractThe observational records have shown a strengthening of the Pacific Walker circulation (PWC) since 1979. However, whether the observed change is forced by external forcing or internal variability remains inconclusive, a solid answer to more societal relevantly question of how the PWC will change in the near future is still a challenge. Here we perform a quantitative estimation on the contributions of external forcing and internal variability to the recent observed PWC strengthening using large ensemble simulations from six state-of-the-art Earth system models. We find the phase transition of the Interdecadal Pacific Oscillation (IPO), which is an internal variability mode related to the Pacific, accounts for approximately 63% (~51–72%) of the observed PWC strengthening. Models with sufficient ensemble members can reasonably capture the observed PWC and IPO changes. We further constrain the projection of PWC change by using climate models’ credit in reproducing the historical phase of IPO. The result shows a high probability of a weakened PWC in the near future.

MONARCHS, TRAVELLERS AND EMPIRE IN THE PACIFIC'S AGE OF REVOLUTIONS

2020 ◽  
Vol 30 ◽  
pp. 77-96
Author(s):  
Sujit Sivasundaram
Keyword(s):  
Pacific Islanders ◽  
Modern World ◽  
Global History ◽  
The Past ◽  
The Pacific ◽  
Cultural Terms ◽  
The Pacific Ocean ◽  
Definition Of ◽  
The Uk ◽  
A Site

AbstractThe Pacific has often been invisible in global histories written in the UK. Yet it has consistently been a site for contemplating the past and the future, even among Britons cast on its shores. In this lecture, I reconsider a critical moment of globalisation and empire, the ‘age of revolutions’ at the end of the eighteenth century and the start of the nineteenth century, by journeying with European voyagers to the Pacific Ocean. The lecture will point to what this age meant for Pacific islanders, in social, political and cultural terms. It works with a definition of the Pacific's age of revolutions as a surge of indigeneity met by a counter-revolutionary imperialism. What was involved in undertaking a European voyage changed in this era, even as one important expedition was interrupted by news from revolutionary Europe. Yet more fundamentally vocabularies and practices of monarchy were consolidated by islanders across the Pacific. This was followed by the outworkings of counter-revolutionary imperialism through agreements of alliance and alleged cessation. Such an argument allows me, for instance, to place the 1806 wreck of the Port-au-Prince within the Pacific's age of revolutions. This was an English ship used to raid French and Spanish targets in the Pacific, but which was stripped of its guns, iron, gunpowder and carronades by Tongans. To chart the trajectory from revolution and islander agency on to violence and empire is to appreciate the unsettled paths that gave rise to our modern world. This view foregrounds people who inhabited and travelled through the earth's oceanic frontiers. It is a global history from a specific place in the oceanic south, on the opposite side of the planet to Europe.

scholarly journals Unknown Tsunami Trigger Hides Along a Creeping Aleutian Fault

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
Cody Sullivan
Keyword(s):  
Pacific Ocean ◽  
Subduction Zone ◽  
The Past ◽  
The Pacific ◽  
The Pacific Ocean

A seismically quiet part of the Aleutian Subduction Zone may have caused tsunamis in the past—and may cause future tsunamis that could travel across the Pacific Ocean.

scholarly journals Pacific Sea Levels Rising Very Slowly and Not Accelerating

2019 ◽  
Vol 38 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Albert Parker ◽  
Clifford Ollier
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Relative Rate ◽  
Tide Gauges ◽  
Sea Levels ◽  
The Past ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Long Term Trend

AbstractOver the past decades, detailed surveys of the Pacific Ocean atoll islands show no sign of drowning because of accelerated sea-level rise. Data reveal that no atoll lost land area, 88.6% of islands were either stable or increased in area, and only 11.4% of islands contracted. The Pacific Atolls are not being inundated because the sea level is rising much less than was thought. The average relative rate of rise and acceleration of the 29 long-term-trend (LTT) tide gauges of Japan, Oceania and West Coast of North America, are both negative, −0.02139 mm yr−1and −0.00007 mm yr−2respectively. Since the start of the 1900s, the sea levels of the Pacific Ocean have been remarkably stable.

scholarly journals Особенности спектров ЯМР -=SUP=-63,65-=/SUP=-Cu в локальном поле образцов полупроводникового минерала CuFeS-=SUB=-2-=/SUB=- из сульфидных месторождений океана

2018 ◽  
Vol 52 (8) ◽  
pp. 836
Author(s):  
В.Л. Матухин ◽  
А.И. Погорельцев ◽  
А.Н. Гавриленко ◽  
С.О. Гарькавый ◽  
Е.В. Шмидт ◽  
...  
Keyword(s):  
Room Temperature ◽  
Global Ocean ◽  
Island Arcs ◽  
Nmr Spectrum ◽  
Nmr Method ◽  
The Pacific ◽  
Different Types ◽  
Asymmetric Shape ◽  
The Pacific Ocean ◽  
Polymetallic Sulfides

AbstractThe results of studying natural samples of CuFeS_2 chalcopyrite mineral from hydrothermal ore manifestations of island arcs of the Pacific Ocean by ^63Cu nuclear magnetic resonance (^63Cu NMR) in a local field at room temperature are presented. The asymmetric shape of the detected resonance lines in the ^63Cu NMR spectrum indicates the presence of at least two overlapping lines. The presence of two overlapping central components can be a consequence of the occurrence of regions with different types of structural distortion near the resonant nuclei. These results show that the pulsed ^63Cu NMR method can be an effective method for studying the physical properties of deep-sea polymetallic sulfides of the global ocean.

scholarly journals Genetic structure of the crown-of-thorns seastar in the Pacific Ocean, with focus on Guam

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1970 ◽  
Author(s):  
Sergio Tusso ◽  
Kerstin Morcinek ◽  
Catherine Vogler ◽  
Peter J. Schupp ◽  
Ciemon F. Caballes ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Pacific Ocean ◽  
Long Distance ◽  
The Past ◽  
The Pacific ◽  
Tropical Coral ◽  
Population Outbreaks ◽  
Geographical Regions ◽  
The Pacific Ocean ◽  
The Western Pacific

Population outbreaks of the corallivorous crown-of-thorns seastar (COTS),Acanthaster ‘planci’ L., are among the most important biological disturbances of tropical coral reefs. Over the past 50 years, several devastating outbreaks have been documented around Guam, an island in the western Pacific Ocean. Previous analyses have shown that in the Pacific Ocean, COTS larval dispersal may be geographically restricted to certain regions. Here, we assess the genetic structure of Pacific COTS populations and compared samples from around Guam with a number of distant localities in the Pacific Ocean, and focused on determining the degree of genetic structure among populations previously considered to be isolated. Using microsatellites, we document substantial genetic structure between 14 localities from different geographical regions in the Pacific Ocean. Populations from the 14 locations sampled were found to be structured in three significantly differentiated groups: (1) all locations immediately around Guam, as well as Kingman Reef and Swains Island; (2) Japan, Philippines, GBR and Vanuatu; and (3) Johnston Atoll, which was significantly different from all other localities. The lack of genetic differentiation between Guam and extremely distant populations from Kingman Reef and Swains Island suggests potential long-distance dispersal of COTS in the Pacific.

Historical ocean heat uptake in CMIP6 Earth System models: global and regional perspectives

2020 ◽  
Author(s):  
Till Kuhlbrodt ◽  
Aurore Voldoire ◽  
Matthew Palmer ◽  
Rachel Killick ◽  
Colin Jones
Keyword(s):  
Time Series ◽  
Climate Models ◽  
Global Climate ◽  
Heat Content ◽  
Global Ocean ◽  
Earth System ◽  
Ocean Heat Uptake ◽  
The Pacific ◽  
Heat Uptake ◽  
Earth System Models

<p>Ocean heat content is arguably one of the most relevant metrics for tracking global climate change and in particular the current global heating. Because of its enormous heat capacity, the global ocean stores about 93 percent of the excess heat in the Earth System. Time series of global ocean heat content (OHC) closely track Earth’s energy imbalance as observed as the net radiative balance at the top of the atmosphere. For these reasons simulated OHC time series are a cornerstone for assessing the scientific performance of Earth System models (ESM) and global climate models. Here we present a detailed analysis of the OHC change in simulations of the historical climate (20<sup>th</sup> century up to 2014) performed with four of the current, state-of-the art generation of ESMs and climate models. These four models are UKESM1, HadGEM3-GC3.1-LL, CNRM-ESM2-1 and CNRM-CM6-1. All four share the same ocean component, NEMO3.6 in the shaconemo eORCA1 configuration, and they all take part in CMIP6, the current Phase 6 of the Coupled Model Intercomparison Project. Analysing a small number of models gives us the opportunity to analyse OHC change for the global ocean as well as for individual ocean basins. In addition to the ensemble means, we focus on some individual ensemble members for a more detailed process understanding. For the global ocean, the two CNRM models reproduce the observed OHC change since the 1960s closely, especially in the top 700 m of the ocean. The two UK models (UKESM1 and HadGEM3-GC3.1-LL) do not simulate the observed global ocean warming in the 1970s and 1980s, and they warm too fast after 1991. We analyse how this varied performance across the models relates to the simulated radiative forcing of the atmosphere. All four models show a smaller ocean heat uptake since 1971, and a larger transient climate response (TCR), than the CMIP5 ensemble mean. Close analysis of a few individual ensemble members indicates a dominant role of heat uptake and deep-water formation processes in the Southern Ocean for variability and change in global OHC. Evaluating OHC change in individual ocean basins reveals that the lack of warming in the UK models stems from the Pacific and Indian basins, while in the Atlantic the OHC change 1971-2014 is close to the observed value. Resolving the ocean warming in depth and time shows that regional ocean heat uptake in the North Atlantic plays a substantial role in compensating small warming rates elsewhere. An opposite picture emerges from the CNRM models. Here the simulated OHC change is close to observations in the Pacific and Indian basins, while tending to be too small in the Atlantic, indicating a markedly different role for the Atlantic meridional overturning circulation (AMOC) and cross-equatorial heat transport in these models.</p>

The Variable Southern Ocean Carbon Sink

2019 ◽  
Vol 11 (1) ◽  
pp. 159-186 ◽  
Author(s):  
Nicolas Gruber ◽  
Peter Landschützer ◽  
Nicole S. Lovenduski
Keyword(s):  
Southern Ocean ◽  
Carbon Sink ◽  
Global Ocean ◽  
The Pacific ◽  
Southward Shift ◽  
Storage Rate ◽  
The Pacific Ocean ◽  
Ocean Models ◽  
Ocean Carbon ◽  
Decadal Predictions

The CO2uptake by the Southern Ocean (<35°S) varies substantially on all timescales and is a major determinant of the variations of the global ocean carbon sink. Particularly strong are the decadal changes characterized by a weakening period of the Southern Ocean carbon sink in the 1990s and a rebound after 2000. The weakening in the 1990s resulted primarily from a southward shift of the westerlies that enhanced the upwelling and outgassing of respired (i.e., natural) CO2. The concurrent reduction in the storage rate of anthropogenic CO2in the mode and intermediate waters south of 35°S suggests that this shift also decreased the uptake of anthropogenic CO2. The rebound and the subsequent strong, decade-long reinvigoration of the carbon sink appear to have been driven by cooling in the Pacific Ocean, enhanced stratification in the Atlantic and Indian Ocean sectors, and a reduced overturning. Current-generation ocean models generally do not reproduce these variations and are poorly skilled at making decadal predictions in this region.

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