scholarly journals The Impact of North Atlantic–Arctic Multidecadal Variability on Northern Hemisphere Surface Air Temperature

2010 ◽  
Vol 23 (21) ◽  
pp. 5668-5677 ◽  
Author(s):  
Vladimir A. Semenov ◽  
Mojib Latif ◽  
Dietmar Dommenget ◽  
Noel S. Keenlyside ◽  
Alexander Strehz ◽  
...  
Keyword(s):  
Climate Variability ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
The Arctic ◽  
Decadal Climate Variability ◽  
Multidecadal Variability ◽  
The North ◽  
Hemisphere Surface ◽  
The North Atlantic ◽  
Decadal Climate

Abstract The twentieth-century Northern Hemisphere surface climate exhibits a long-term warming trend largely caused by anthropogenic forcing, with natural decadal climate variability superimposed on it. This study addresses the possible origin and strength of internal decadal climate variability in the Northern Hemisphere during the recent decades. The authors present results from a set of climate model simulations that suggest natural internal multidecadal climate variability in the North Atlantic–Arctic sector could have considerably contributed to the Northern Hemisphere surface warming since 1980. Although covering only a few percent of the earth’s surface, the Arctic may have provided the largest share in this. It is hypothesized that a stronger meridional overturning circulation in the Atlantic and the associated increase in northward heat transport enhanced the heat loss from the ocean to the atmosphere in the North Atlantic region and especially in the North Atlantic portion of the Arctic because of anomalously strong sea ice melt. The model results stress the potential importance of natural internal multidecadal variability originating in the North Atlantic–Arctic sector in generating interdecadal climate changes, not only on a regional scale, but also possibly on a hemispheric and even a global scale.

scholarly journals Multiple Equilibria as a Possible Mechanism for Decadal Variability in the North Atlantic Ocean

2015 ◽  
Vol 28 (22) ◽  
pp. 8907-8922 ◽  
Author(s):  
Andreas Born ◽  
Juliette Mignot ◽  
Thomas F. Stocker
Keyword(s):  
Climate Variability ◽  
Conceptual Model ◽  
North Atlantic ◽  
Multiple Equilibria ◽  
Decadal Variability ◽  
Heat Content ◽  
Decadal Climate Variability ◽  
The North ◽  
The North Atlantic ◽  
Decadal Climate

Abstract Decadal climate variability in the North Atlantic has received increased attention in recent years, because modeling results suggest predictability of heat content and circulation indices several years ahead. However, determining the applicability of these results in the real world is challenging because of an incomplete understanding of the underlying mechanisms. Here, the authors show that recent attempts to reconstruct the decadal variations in one of the dominant circulation systems of the region, the subpolar gyre (SPG), are not always consistent. A coherent picture is partly recovered by a simple conceptual model solely forced by reanalyzed surface air temperatures. This confirms that surface heat flux indeed plays a leading role for this type of variability, as has been suggested in previous studies. The results further suggest that large variations in the SPG correspond to the crossing of a bifurcation point that is predicted from idealized experiments and an analytical solution of the model used herein. Performance of this conceptual model is tested against a statistical stochastic model. Hysteresis and the existence of two stable modes of the SPG circulation shape its response to forcing by atmospheric temperatures. The identification of the essential dynamics and the reduction to a minimal model of SPG variability provide a quantifiable basis and a framework for future studies on decadal climate variability and predictability.

scholarly journals The impacts of oceanic deep temperature perturbations in the North Atlantic on decadal climate variability and predictability

2017 ◽  
Vol 51 (5-6) ◽  
pp. 2341-2357 ◽  
Author(s):  
Agathe Germe ◽  
Florian Sévellec ◽  
Juliette Mignot ◽  
Alexey Fedorov ◽  
Sébastien Nguyen ◽  
...  
Keyword(s):  
Climate Variability ◽  
North Atlantic ◽  
Decadal Climate Variability ◽  
The North ◽  
The North Atlantic ◽  
Deep Temperature ◽  
Decadal Climate

scholarly journals Multidisciplinary investigations of the Northern Atlantic and Arctic in 71th cruise of R/V «Akademik Mstislav Keldysh»

2019 ◽  
Vol 59 (3) ◽  
pp. 510-512
Author(s):  
A. N. Novigatsky ◽  
S. V. Gladyshev ◽  
A. A. Klyuvitkin ◽  
N. V. Kozina ◽  
V. A. Artemyev ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
North Atlantic ◽  
The Arctic ◽  
International Program ◽  
The North ◽  
Unique Material ◽  
Sedimentary System ◽  
Northern Atlantic ◽  
The North Atlantic

The article briefly shows the results of the expedition, expanding Russia’s contribution to the international program CLIVAR (Climate Variability and Predictability), aimed at studying and predicting climate change. The geological part of the expedition is aimed at studying the sedimentary system of the North Atlantic and the Arctic. During the voyage, a unique material was received, requiring additional analysis and further publication.

scholarly journals Sea ice-air interactions amplify multidecadal variability in the North Atlantic and Arctic region

2020 ◽  
Author(s):  
Aiguo Dai ◽  
Jiechun Deng
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Arctic Sea Ice ◽  
Surface Fluxes ◽  
Meridional Overturning Circulation ◽  
The Arctic ◽  
Multidecadal Variability ◽  
The North ◽  
Arctic Sea ◽  
The North Atlantic

Abstract Winter surface air temperature (Tas) over the Barents-Kara Seas (BKS) and other Arctic regions has experienced rapid warming since the late 1990 that has been linked to the concurring cooling over Eurasia1-3. However, the cause of this accelerated BKS warming is not well understood, and whether and how internal variability may have contributed to this warming is unclear. Through analyses of observations and model simulations, we show that two-way interactions between sea ice and air amplify multidecadal variability in Arctic sea-ice cover (SIC) and sea surface temperatures (SST) from the North Atlantic to BKS, and produce large multidecadal variations in Tas over the BKS, Greenland-Norwegian Seas and Baffin Bay. Advection of SST anomalies from the North Atlantic to the Arctic causes SIC to change, which produces large anomalies in surface energy fluxes and Tas. However, the sea ice-air interactions also amplify the variations in SIC and SST, and the Atlantic Meridional Overturning Circulation (AMOC) mainly through local surface fluxes. When sea ice is fixed or melts away under increasing CO2, not only Arctic Tas multidecadal variations disappear, but also the SIC, SST and AMOC variations are greatly reduced. The results suggest that sea ice-air interactions are vital for multidecadal climate variability not only in the Arctic but also in the North Atlantic, similar to air-sea interactions for tropical climate. As Arctic sea ice is projected to melt away4,5, these interactions and thus multidecadal variability from the North Atlantic to the Arctic will likely weaken in the coming decades.

Understanding cyclone variability in the Barents Sea

2020 ◽  
Author(s):  
Erica Madonna ◽  
Gabriel Hes ◽  
Clio Michel ◽  
Camille Li ◽  
Peter Yu Feng Siew
Keyword(s):  
Climate Variability ◽  
Sea Ice ◽  
North Atlantic ◽  
Barents Sea ◽  
The Arctic ◽  
High Latitudes ◽  
The North ◽  
The Barents Sea ◽  
The North Atlantic ◽  
Cyclone Frequency

<p>Extratropical cyclones are a key player for the global energy budget as they transport a large amount of moisture and heat from mid- to high-latitudes. One of the main corridors for cyclones entering the Arctic from the North Atlantic is the Barents Sea, a region that has experienced the largest decrease in winter sea ice during the past decades. On the one hand, some studies showed that moisture transported by cyclones to the Arctic can lead to drastic temperature increases and sea ice melt. On the other hand, it has been suggested that the location of the sea ice edge can influence the tracks of cyclones. Therefore, it is crucial to understand what controls cyclone tracks through the Barents Sea into the Arctic to explain and potentially predict climate variability at high latitudes.</p><p>To address this question, we track cyclones from 1979 to 2018 in the ERA-Interim data set, characterizing and quantifying them depending on their genesis location and path. The focus is on cyclones entering the Barents Sea from the North Atlantic as they carry the most moisture into the Arctic. Despite a clear declining trend in sea ice in the Barents Sea, our results show neither significant changes in cyclone frequency nor in their tracks. However, we find that the large-scale flow and in particular the presence or absence of blocking in the Barents Sea influence the cyclone frequency in this region, providing a potential mechanism that controls high latitude climate variability.</p>

Multidecadal Variability of North Atlantic Temperature and Salinity during the Twentieth Century

2005 ◽  
Vol 18 (21) ◽  
pp. 4562-4581 ◽  
Author(s):  
I. V. Polyakov ◽  
U. S. Bhatt ◽  
H. L. Simmons ◽  
D. Walsh ◽  
J. E. Walsh ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
The Arctic ◽  
Multidecadal Variability ◽  
The North ◽  
Basin Scale ◽  
Dominant Feature ◽  
The North Atlantic

Abstract Substantial changes occurred in the North Atlantic during the twentieth century. Here the authors demonstrate, through the analysis of a vast collection of observational data, that multidecadal fluctuations on time scales of 50–80 yr are prevalent in the upper 3000 m of the North Atlantic Ocean. Spatially averaged temperature and salinity from the 0–300- and 1000–3000-m layers vary in opposition: prolonged periods of cooling and freshening (warming and salinification) in one layer are generally associated with opposite tendencies in the other layer, consistent with the notion of thermohaline overturning circulation. In the 1990s, widespread cooling and freshening was a dominant feature in the 1000–3000-m layer, whereas warming and salinification generally dominated in the upper 300 m, except for the subpolar North Atlantic where complex exchanges with the Arctic Ocean occur. The single-signed basin-scale pattern of multidecadal variability is evident from decadal 1000–3000-m temperature and salinity fields, whereas upper-ocean temperature and salinity distributions have a more complicated spatial pattern. Results suggest a general warming trend of 0.012° ± 0.009°C decade−1 in the upper-3000-m North Atlantic over the last 55 yr of the twentieth century, although during this time there are periods in which short-term trends are strongly amplified by multidecadal variability. Since warming (cooling) is generally associated with salinification (freshening) for these large-scale fluctuations, qualitatively tracking the mean temperature–salinity relationship, vertical displacement of isotherms appears to play an important role in this warming and in other observed fluctuations. Finally, since the North Atlantic Ocean plays a crucial role in establishing and regulating global thermohaline circulation, the multidecadal fluctuations of the heat and freshwater balance discussed here should be considered when assessing long-term climate change and variability, both in the North Atlantic and at global scales.

scholarly journals Climate variability in subarctic area for the last two millennia

2017 ◽  
Author(s):  
Marie Nicolle ◽  
Maxime Debret ◽  
Nicolas Massei ◽  
Christophe Colin ◽  
Anne deVernal ◽  
...  
Keyword(s):  
Climate Variability ◽  
North Atlantic ◽  
The Arctic ◽  
Proxy Data ◽  
Climatic Trend ◽  
The North ◽  
Recent Warming ◽  
Recent Climate ◽  
The North Atlantic ◽  
The Last Two Millennia

Abstract. To put in perspective the recent climate change, it is necessary to extend the instrumental climate records with proxy data from palaeoclimate archives. Arctic climate variability for the last two millennia has been investigated using statistical and signal analyses from three regionally averaged records from the North Atlantic, Siberia and Alaska based on many sort of proxy data archived in the Arctic 2k database. In the North Atlantic and Alaska areas, the major climatic trend is characterized by long-term cooling interrupted by the recent warming that started at the beginning of the 19th century. This cooling trend is not clearly visible in the Siberian region. The Little Ice Age (LIA) was identified from the individual series and is characterized by an important spatial and temporal expression of climate variability. It started at the earliest by around 1200 AD and ended at the latest in the middle of the 20th century. The large spread temporal coverage of LIA did not show regional consistency or particular spatial distribution and did not show relationship with archive/proxy type either. A focus on the last two centuries shows a recent warming characterized by a well-marked warming trend paralleling with increasing greenhouse gas emissions. It also shows a multi-decadal variability likely due to natural processes acting on the internal climate system variability at regional scale. A 16–30 years cycle is found in Alaska and seems to be linked to the Pacific Decadal Oscillation (PDO) whereas ~ 20–30 and ~ 50–90 years periodicities characterize the North Atlantic climate regime, likely in relation with the Atlantic Multidecadal Oscillation (AMO). These regional features are apparently linked to the sea-ice cover fluctuations through ice-temperature positive feedback.

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