scholarly journals Temporal Variability in the Expression of the Arctic Oscillation in the North Pacific

2009 ◽  
Vol 22 (11) ◽  
pp. 3110-3126 ◽  
Author(s):  
Hongxu Zhao ◽  
G. W. K. Moore
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Arctic Oscillation ◽  
Low Frequency ◽  
Dominant Mode ◽  
Ice Age ◽  
The Arctic ◽  
The North ◽  
The Arctic Oscillation ◽  
The North Pacific

Abstract Although the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) have been identified as important modes of climate variability during the Northern Hemisphere (NH) winter, whether the AO or the NAO is more fundamental to the description of this variability, especially in the North Pacific, is still an open question. An important contributor to this uncertainty is the lack of knowledge of the low-frequency linkages between the North Atlantic and North Pacific Oceans. This paper explores the linkage between the two oceanic basins on interdecadal time scales using the sea level pressure (SLP) field during the twentieth century. In particular, it is shown that the winter mean SLP in the North Pacific was positively correlated with the sign of the NAO during the periods of 1925–50 and 1980–98, which resulted in the classical AO pattern being the dominant mode in the NH. In contrast, during the period of 1951–79, the winter mean SLP in the two basins was decoupled, resulting in a dominant mode that more closely resembled the NAO. Using paleoclimate reconstructions, it is also shown that this interdecadal variability in the North Pacific climate began around 1850, which is nominally considered to be the end of the Little Ice Age.

scholarly journals The Nature of the Arctic Oscillation and Diversity of the Extreme Surface Weather Anomalies It Generates

2017 ◽  
Vol 30 (14) ◽  
pp. 5563-5584 ◽  
Author(s):  
Panxi Dai ◽  
Benkui Tan
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Arctic Oscillation ◽  
Weather Prediction ◽  
The Arctic ◽  
The North ◽  
Surface Weather ◽  
The North Atlantic ◽  
The Arctic Oscillation ◽  
The North Pacific

Through a cluster analysis of daily NCEP–NCAR reanalysis data, this study demonstrates that the Arctic Oscillation (AO), defined as the leading empirical orthogonal function (EOF) of 250-hPa geopotential height anomalies, is not a unique pattern but a continuum that can be well approximated by five discrete, representative AO-like patterns. These AO-like patterns grow simultaneously from disturbances in the North Pacific, the North Atlantic, and the Arctic, and both the feedback from the high-frequency eddies in the North Pacific and North Atlantic and propagation of the low-frequency wave trains from the North Pacific across North America into the North Atlantic play important roles in the pattern formation. Furthermore, it is shown that the structures and frequencies of occurrence of the five AO-like patterns are significantly modulated by El Niño–Southern Oscillation (ENSO). Warm (cold) ENSO enhances the negative (positive) AO phase, compared with ENSO neutral winters. Finally, the surface weather effects of these AO-like patterns and their implications for the AO-related weather prediction and the AO-North Atlantic Oscillation (NAO) relationship are discussed.

scholarly journals Heat transport pathways into the Arctic and their connections to surface air temperatures

2019 ◽  
Vol 19 (6) ◽  
pp. 3927-3937 ◽  
Author(s):  
Daniel Mewes ◽  
Christoph Jacobi
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Large Scale ◽  
The Arctic ◽  
Positive Temperature ◽  
Transport Pathways ◽  
Temperature Anomalies ◽  
The North ◽  
The North Atlantic ◽  
The North Pacific

Abstract. Arctic amplification causes the meridional temperature gradient between middle and high latitudes to decrease. Through this decrease the large-scale circulation in the midlatitudes may change and therefore the meridional transport of heat and moisture increases. This in turn may increase Arctic warming even further. To investigate patterns of Arctic temperature, horizontal transports and their changes in time, we analysed ERA-Interim daily winter data of vertically integrated horizontal moist static energy transport using self-organizing maps (SOMs). Three general transport pathways have been identified: the North Atlantic pathway with transport mainly over the northern Atlantic, the North Pacific pathway with transport from the Pacific region, and the Siberian pathway with transport towards the Arctic over the eastern Siberian region. Transports that originate from the North Pacific are connected to negative temperature anomalies over the central Arctic. These North Pacific pathways have been becoming less frequent during the last decades. Patterns with origin of transport in Siberia are found to have no trend and show cold temperature anomalies north of Svalbard. It was found that transport patterns that favour transport through the North Atlantic into the central Arctic are connected to positive temperature anomalies over large regions of the Arctic. These temperature anomalies resemble the warm Arctic–cold continents pattern. Further, it could be shown that transport through the North Atlantic has been becoming more frequent during the last decades.

The North Atlantic Oscillation and the Arctic Oscillation favour harmful algal blooms in SW Europe

Harmful Algae ◽  
2014 ◽  
Vol 39 ◽  
pp. 121-126 ◽  
Author(s):  
José C. Báez ◽  
Raimundo Real ◽  
Victoria López-Rodas ◽  
Eduardo Costas ◽  
A. Enrique Salvo ◽  
...  
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Arctic Oscillation ◽  
The Arctic ◽  
The North ◽  
The North Atlantic ◽  
The Arctic Oscillation ◽  
The North Atlantic Oscillation

Bathyal benthic polychaetes from the N.E. Atlantic Ocean, S.W. of the British Isles

1983 ◽  
Vol 63 (3) ◽  
pp. 593-608 ◽  
Author(s):  
Jørgen B. Kirkegaard
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
New Genus ◽  
New Combination ◽  
The Arctic ◽  
British Isles ◽  
The North ◽  
Two New Species ◽  
The North Atlantic ◽  
The North Pacific

From bathyal depths in the Bay of Biscay, southwest of the British Isles, 89 species of polychaetes are described, among which are two new species, one new genus, and one new Combination, i.e. Pholoe fauveli sp. nov., Paracapitella southwardi n.gen., n. sp., and Galathowenia oculata, new combination. Of the species taken, 52 % are also known from abyssal depths. The bathyal polychaete fauna of the North Atlantic seems to be common with that of the Arctic and the North Pacific.

scholarly journals Genetic diversity and biogeography in Chaetomorpha melagonium (Ulvophyceae, Cladophorales) based on internal transcribed spacer (ITS rDNA) sequences

2017 ◽  
Vol 60 (3) ◽  
Author(s):  
Christian Boedeker ◽  
Frederik Leliaert ◽  
Giuseppe C. Zuccarello
Keyword(s):  
Genetic Diversity ◽  
North Atlantic ◽  
North Pacific ◽  
Internal Transcribed Spacer ◽  
Distinct Species ◽  
The Arctic ◽  
The North ◽  
Rdna Sequences ◽  
The North Atlantic ◽  
The North Pacific

Abstractis a morphologically distinct species of green algae that occurs throughout the North Atlantic, the North Pacific and the Arctic Ocean. In this study, we analyzed the intraspecific genetic diversity among 14 samples of

scholarly journals Dynamics of the Northern Annular Mode at Weekly Time Scales

2015 ◽  
Vol 72 (12) ◽  
pp. 4569-4590 ◽  
Author(s):  
Gwendal Rivière ◽  
Marie Drouard
Keyword(s):  
Wave Propagation ◽  
North America ◽  
North Atlantic ◽  
North Pacific ◽  
Low Frequency ◽  
Northern Annular Mode ◽  
The North ◽  
Momentum Fluxes ◽  
The North Atlantic ◽  
The North Pacific

Abstract Rapid onsets of positive and negative tropospheric northern annular mode (NAM) events during boreal winters are studied using ERA-Interim datasets. The NAM anomalies first appear in the North Pacific from low-frequency Rossby wave propagation initiated by anomalous convection in the western tropical Pacific around 2 weeks before the peak of the events. For negative NAM, the enhanced convection leads to a zonal acceleration of the Pacific jet, while for positive NAM, the reduced convection leads to a poleward-deviated jet in its exit region. The North Atlantic anomalies, which correspond to North Atlantic Oscillation (NAO) anomalies, are formed in close connection with the North Pacific anomalies via downstream propagation of low-frequency planetary-scale and high-frequency synoptic waves, the latter playing a major role during the last onset week. Prior to positive NAM, the generation of synoptic waves in the North Pacific and their downstream propagation is strong. The poleward-deviated Pacific jet favors a southeastward propagation of the waves across North America and anticyclonic breaking in the North Atlantic. The associated strong poleward eddy momentum fluxes push the Atlantic jet poleward and form the positive NAO phase. Conversely, prior to negative NAM, synoptic wave propagation across North America is significantly reduced and more zonal because of the more zonally oriented Pacific jet. This, together with a strong eddy generation in the North Atlantic, leads to equatorward eddy momentum fluxes, cyclonic wave breaking, and the formation of the negative NAO phase. Even though the stratosphere may play a role in some individual cases, it is not the main driver of the composited tropospheric NAM events.

scholarly journals The influence of Arctic air masses on climatic conditions of the snow accumulation period in the center of the European territory of Russia

2021 ◽  
pp. 16-25
Author(s):  
Julia Nikolaevna Chizhova
Keyword(s):  
North Atlantic ◽  
Arctic Oscillation ◽  
Winter Precipitation ◽  
Climatic Conditions ◽  
The Arctic ◽  
Air Masses ◽  
The North ◽  
The Arctic Oscillation ◽  
The North Atlantic Oscillation ◽  
The Relationship

The subject of this article is exmination of the influence of the Arctic air flow on the climatic conditions of the winter period in the center of the European territory of Russia (Moscow). In recent years, the question of the relationship between regional climatic conditions and such global circulation patterns as the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AK) has become increasingly important. Based on the data of long-term observations of temperature and precipitation, the relationship with the AK and NAO was considered. For the winter months of the period 2014-2018, the back trajectories of the movement of air masses were computed for each date of precipitation to identify the sources of precipitation. The amount of winter precipitation that forms the snow cover of Moscow has no connection with either the North Atlantic Oscillation or the Arctic Oscillation. The Moscow region is located at the intersection of the zones of influence of positive and negative phases of both cyclonic patterns (AK and NAO), which determine the weather in the Northern Hemisphere. For the winter months, a correlation between the surface air temperature and NAO (r = 0.72) and AK (r = 0.66) was established. Winter precipitation in the center of the European territory of Russiais mainly associated with the unloading of Atlantic air masses. Arctic air masses relatively rarely invade Moscow region and bring little precipitation (their contribution does not exceed 12% of the total winter precipitation).

scholarly journals Multidecadal Fluctuation of the Wintertime Arctic Oscillation Pattern and Its Implication

2018 ◽  
Vol 31 (14) ◽  
pp. 5595-5608 ◽  
Author(s):  
Hainan Gong ◽  
Lin Wang ◽  
Wen Chen ◽  
Debashis Nath
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Arctic Oscillation ◽  
Surface Air Temperature ◽  
Western North America ◽  
Oscillation Pattern ◽  
The North ◽  
The Pacific ◽  
The North Atlantic ◽  
The North Pacific

The multidecadal fluctuations in the patterns and teleconnections of the winter mean Arctic Oscillation (AO) are investigated based on observational and reanalysis datasets. Results show that the Atlantic center of the AO pattern remains unchanged throughout the period 1920–2010, whereas the Pacific center of the AO is strong during 1920–59 and 1986–2010 and weak during 1960–85. Consequently, the link between the AO and the surface air temperature over western North America is strong during 1920–59 and 1986–2010 and weak during 1960–85. The time-varying Pacific center of the AO motivates a revisit to the nature of the AO from the perspective of decadal change. It reveals that the North Pacific mode (NPM) and North Atlantic Oscillation (NAO) are the inherent regional atmospheric modes over the North Pacific and North Atlantic, respectively. Their patterns over the North Pacific and North Atlantic remain stable and change little with time during 1920–2010. The Atlantic center of the AO always resembles the NAO over the North Atlantic, but the Pacific center of the AO only resembles the NPM over the North Pacific when the NPM–NAO coupling is strong. These results suggest that the AO seems to be fundamentally rooted in the variability over the North Atlantic and that the annular structure of the AO very likely arises from the coupling of the atmospheric modes between the North Pacific and North Atlantic.

scholarly journals The North Pacific Diatom Species Neodenticula seminae in the Modern and Holocene Sediments of the North Atlantic and Arctic

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 173
Author(s):  
Alexander Matul ◽  
Galina Kh. Kazarina
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Diatom Species ◽  
Pacific Water ◽  
The North ◽  
Holocene Sediments ◽  
The North Atlantic ◽  
The North Pacific

The paper presents micropaleontological information and observations of the North Pacific diatom species Neodenticula (N.) seminae (Simonsen and Kanaya) Akiba and Yanagisawa in the surface and Holocene sediments from the North Atlantic, Nordic, and Arctic Seas. The compilation of previously published data and new findings of this study on N. seminae in the surface sediments shows its broad occurrence as a usual element of the modern diatom microflora in the Nordic, Labrador, and Irminger Seas. The recent migration of N. seminae from its native area, the Subarctic Pacific, reflects the oceanographic shift in the late 1990s as greater transport of the warmer surface Pacific water to the Arctic causes Arctic sea-ice reduction. Micropaleontological studies of the Holocene sediments document the multiple events of N. seminae appearance in the Arctic during the latest Pleistocene and Holocene warming intervals. These observations can suggest the events of the increased influence of the North Pacific water on the Arctic environments in the past, not just during the recent warm climate amplification.

scholarly journals Diversity of the Wintertime Arctic Oscillation Pattern among CMIP5 Models: Role of the Stratospheric Polar Vortex

2019 ◽  
Vol 32 (16) ◽  
pp. 5235-5250 ◽  
Author(s):  
Hainan Gong ◽  
Lin Wang ◽  
Wen Chen ◽  
Renguang Wu ◽  
Wen Zhou ◽  
...  
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Arctic Oscillation ◽  
Climate Models ◽  
Polar Vortex ◽  
Cmip5 Models ◽  
Stratospheric Polar Vortex ◽  
The North ◽  
The North Atlantic ◽  
The North Pacific

AbstractThe wintertime Arctic Oscillation (AO) pattern in phase 5 of the Coupled Model Intercomparison Project (CMIP5) climate models displays notable differences from the reanalysis. The North Pacific center of the AO pattern is larger in the ensemble mean of 27 models than in the reanalysis, and the magnitude of the North Pacific center of the AO pattern varies largely among the models. This study investigates the plausible sources of the diversity of the AO pattern in the models. Analysis indicates that the amplitude of the North Pacific center is associated with the coupling between the North Pacific and North Atlantic, which in turn is primarily modulated by the strength of the stratospheric polar vortex. A comparative analysis is conducted for the strong polar vortex (SPV) and weak polar vortex (WPV) models. It reveals that a stronger stratospheric polar vortex induces more planetary waves to reflect from the North Pacific to the North Atlantic and more wave activity fluxes to propagate from the North Pacific to the North Atlantic in the SPV models than in the WPV models. Thus, the coupling of atmospheric circulation between the North Pacific and North Atlantic is stronger in the SPV models, which facilitates more North Pacific variability to be involved in the AO variability and induces a stronger North Pacific center in the AO pattern. The increase in vertical resolution may improve the simulation of the stratospheric polar vortex and thereby reduces the model biases in the North Pacific–North Atlantic coupling and thereby the amplitude of the North Pacific center of the AO pattern in models.

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