scholarly journals On the Structure and Teleconnections of North Atlantic Decadal Variability

2011 ◽  
Vol 24 (9) ◽  
pp. 2209-2223 ◽  
Author(s):  
Francisco J. Álvarez-García ◽  
María J. OrtizBevia ◽  
William D. CabosNarvaez
Keyword(s):  
North Atlantic ◽  
Time Scale ◽  
Decadal Variability ◽  
The North ◽  
The Pacific ◽  
Tropical North Atlantic ◽  
Decadal Variations ◽  
The Pacific Ocean ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract Decadal variability in the North Atlantic has been associated in the literature with a tripolar pattern of sea surface temperature (SST) anomalies that show one sign in the western midlatitudinal North Atlantic and the opposite in the subpolar and tropical North Atlantic. The present analysis of observed SST from 1870 to 2009 leads to the dissection of the SST tripole into two components, each with a different time scale in the decadal band and different teleconnections in the Atlantic basin; while the subpolar and tropical poles present quasi-decadal variations with a period of about 9 years, essentially uncorrelated with other parts of the basin, the center of action in the western midlatitudes is characterized by a longer time scale of about 14 years and significant correlations with the tropical South Atlantic and the Norwegian and North Sea(s). The 9-yr period variations are associated with an atmospheric configuration resembling the east Atlantic pattern, whereas the 14-yr period fluctuations seem to be related to the North Atlantic Oscillation pattern. Each component also bears a different relationship with the decadal variability in the 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.

On the Role of Atmospheric Teleconnections in Climate

2008 ◽  
Vol 21 (12) ◽  
pp. 2990-3001 ◽  
Author(s):  
Anastasios A. Tsonis ◽  
Kyle L. Swanson ◽  
Geli Wang
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Recent Application ◽  
The North ◽  
The Pacific ◽  
Atmospheric Teleconnections ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
The Tropics

Abstract In a recent application of networks to 500-hPa data, it was found that supernodes in the network correspond to major teleconnection. More specifically, in the Northern Hemisphere a set of supernodes coincides with the North Atlantic Oscillation (NAO) and another set is located in the area where the Pacific–North American (PNA) and the tropical Northern Hemisphere (TNH) patterns are found. It was subsequently suggested that the presence of atmospheric teleconnections make climate more stable and more efficient in transferring information. Here this hypothesis is tested by examining the topology of the complete network as well as of the networks without teleconnections. It is found that indeed without teleconnections the network becomes less stable and less efficient in transferring information. It was also found that the pattern chiefly responsible for this mechanism in the extratropics is the NAO. The other patterns are simply a linear response of the activity in the tropics and their role in this mechanism is inconsequential.

scholarly journals Is the decadal variability in the tropical Atlantic a precursor to the NAO?

2008 ◽  
Vol 26 (12) ◽  
pp. 4075-4080 ◽  
Author(s):  
I. Wainer ◽  
J. Servain ◽  
G. Clauzet
Keyword(s):  
North Atlantic ◽  
Decadal Variability ◽  
Periodic Oscillation ◽  
Tropical Atlantic ◽  
The Past ◽  
The North ◽  
Decadal Scale ◽  
Decadal Variations ◽  
The North Atlantic Oscillation ◽  
The Tropics

Abstract. In the past two decades climate research in the tropical Atlantic with respect to the inter-hemispheric gradient of sea surface temperature (SST) emphasized the predominance of decadal-scale variability. Our results show that this mode of variability is prevalent only for part of the last 130-years record (the 1880s, the 1920s and, especially, the 1970s). There is a lag of a few months between the decadal variations of the inter-hemispheric gradient of SST and the decadal variability of the North Atlantic Oscillation (NAO). This seems to indicate that the 10-year variability first develops in the tropics and then propagates polewards. The inter-hemispheric gradient of SST mode should be thought as episodic and not as a periodic oscillation.

Amblyopsoides ohlinii (W.M. Tattersall, 1951) (Peracarida, Mysida, Mysidae) in western Mexico

Zootaxa ◽  
2020 ◽  
Vol 4878 (1) ◽  
pp. 169-181
Author(s):  
JOSÉ CARLOS HERNÁNDEZ-PAYÁN ◽  
MICHEL E. HENDRICKX
Keyword(s):  
North Atlantic ◽  
First Record ◽  
Sem Images ◽  
Western Mexico ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Atlantic ◽  
First Time ◽  
The North Pacific

The rare pelagic mysid Amblyopsoides ohlinii (W.M. Tattersall, 1951) is reported for the first time off western Mexico and represents the first record in the Pacific Ocean south of Japan and the Kurile-Kamchatka Trench. So far, this species only has been recorded from seven localities in the North Atlantic and in the North Pacific. A complete description of the only specimen available (a male), including illustrations of all appendages and SEM images of the mandibles, is provided.

scholarly journals Will Global Warming Suppress North Atlantic Tripole Decadal Variability?

2012 ◽  
Vol 25 (6) ◽  
pp. 2040-2055 ◽  
Author(s):  
Yun Yang ◽  
Lixin Wu ◽  
Changfang Fang
Keyword(s):  
Global Warming ◽  
North Atlantic ◽  
Time Scale ◽  
Decadal Variability ◽  
Buoyancy Frequency ◽  
The North ◽  
Ocean Atmosphere ◽  
The North Atlantic ◽  
Partial Blocking ◽  
Partial Coupling

Abstract In this paper, the modulations of the North Atlantic tripole (NAT) decadal variability from global warming are studied by conducting a series of coupled ocean–atmosphere experiments using the Fast Ocean Atmosphere Model (FOAM). The model reasonably captures the observed NAT decadal variability with a preferred time scale of about 11 years. With the aid of partial-blocking and partial-coupling experiments, it is found that the NAT decadal cycle can be attributed to oceanic planetary wave adjustment in the subtropical basin and ocean–atmosphere coupling over the North Atlantic. In a doubled CO2 experiment, the spatial pattern of the NAT is preserved; however, the decadal cycle is significantly suppressed. This suppression appears to be associated with the acceleration of oceanic planetary waves due to an increase of buoyancy frequency in global warming. This shortens the time from a decadal to an interannual time scale for the first-mode baroclinic Rossby waves to cross the subtropical North Atlantic basin, the primary memory for the NAT decadal variability in the model. The modeling study also found that the global warming does not modulate the North Atlantic air–sea coupling significantly, but it may be model dependent.

scholarly journals Sea State Decadal Variability in the North Atlantic: A Review

Climate ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 173
Author(s):  
Antoine Hochet ◽  
Guillaume Dodet ◽  
Fabrice Ardhuin ◽  
Mark Hemer ◽  
Ian Young
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Decadal Variability ◽  
Ocean Waves ◽  
Sea State ◽  
Ship Routing ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Long-term changes of wind-generated ocean waves have important consequences for marine engineering, coastal management, ship routing, and marine spatial planning. It is well-known that the multi-annual variability of wave parameters in the North Atlantic is tightly linked to natural fluctuations of the atmospheric circulation, such as the North Atlantic Oscillation. However, anthropogenic climate change is also expected to influence sea states over the long-term through the modification of atmospheric and ocean circulation and melting of sea ice. Due to the relatively short duration of historical sea state observations and the significant multi-decadal variability in the sea state signal, disentangling the anthropogenic signal from the natural variability is a challenging task. In this article, the literature on inter-annual to multi-decadal variability of sea states in the North Atlantic is reviewed using data from both observations and model reanalysis.

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