scholarly journals The response of freshwater ecosystems to climate variability associated with the North Atlantic Oscillation

2003 ◽  
pp. 263-279 ◽  
Author(s):  
Dietmar Straile ◽  
David M. Livingstone ◽  
Gesa A. Weyhenmeyer ◽  
D. Glen George
Keyword(s):  
Climate Variability ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Freshwater Ecosystems ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

scholarly journals Bivariate Modelling of a Teleconnection Index and Extreme Rainfall in a Small North Atlantic Island

Climate ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 86
Author(s):  
Luis Angel Espinosa ◽  
Maria Manuela Portela ◽  
João Dehon Pontes Filho ◽  
Martina Zelenakova
Keyword(s):  
Climate Variability ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Extreme Rainfall ◽  
Small Island ◽  
Return Periods ◽  
Rainfall Events ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

This paper explores practical applications of bivariate modelling via copulas of two likely dependent random variables, i.e., of the North Atlantic Oscillation (NAO) coupled with extreme rainfall on the small island of Madeira, Portugal. Madeira, due to its small size (∼740 km2), very pronounced mountain landscape, and location in the North Atlantic, experiences a wide range of rainfall regimes, or microclimates, which hamper the analyses of extreme rainfall. Previous studies showed that the influence of the North Atlantic Oscillation (NAO) on extreme rainfall is at its largest in the North Atlantic sector, with the likelihood of increased rainfall events from December through February, particularly during negative NAO phases. Thus, a copula-based approach was adopted for teleconnection, aiming at assigning return periods of daily values of an NAO index (NAOI) coupled with extreme daily rainfalls—for the period from December 1967 to February 2017—at six representative rain gauges of the island. The results show that (i) bivariate copulas describing the dependence characteristics of the underlying joint distributions may provide useful analytical expressions of the return periods of the coupled previous NAOI and extreme rainfall and (ii) that recent years show signs of increasing climate variability with more anomalous daily negative NAOI along with higher extreme rainfall events. These findings highlight the importance of multivariate modelling for teleconnections of prominent patterns of climate variability, such as the NAO, to extreme rainfall in North Atlantic regions, especially in small islands that are highly vulnerable to the effects of abrupt climate variability.

scholarly journals Volcanic imprint in the North Atlantic climate variability as recorded by stable water isotopes of Greenland ice cores

2019 ◽  
Author(s):  
Hera Guðlaugsdóttir ◽  
Jesper Sjolte ◽  
Árný Erla Sveinbjörnsdóttir ◽  
Hans Christian Steen-Larsen
Keyword(s):  
Climate Variability ◽  
North Atlantic Oscillation ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
High Latitude ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract. Volcanic eruptions are important drivers of climate variability on both seasonal and multi-decadal time scales as a result of atmosphere-ocean coupling. While the direct response after equatorial eruptions emerges as the positive phase of the North Atlantic Oscillation in the first two years after an eruption, less is known about high latitude northern hemisphere eruptions. In this study we assess the difference between equatorial and high latitude volcanic eruptions through the reconstructed atmospheric circulation and stable water isotope records of Greenland ice cores for the last millennia (1241–1979 CE), where the coupling mechanism behind the long-term response is addressed. The atmospheric circulation is studied through the four main modes of climate variability in the North Atlantic, the Atlanti Ridge (AtR), Scandinavian Blocking (ScB) and the positive and negative phase of the North Atlantic Oscillation (NAO+/NAO−). We report a difference in the atmospheric circulation response after equatorial eruptions compared to the response after high latitude eruptions, where NAO+ and AtR seem to be more associated with equatorial eruptions while NAO- and ScB seems to follow high latitude eruptions. This response is present during the first five years and then again in years 8–12 after both equatorial and high latitude eruptions. Such a prolonged response is evidence of an ocean-atmosphere coupling that is initiated through different mechanisms, where we suspect sea ice to play a key role.

Volcanic imprint in the North Atlantic climate variability as recorded by stable water isotopes of Greenland ice cores

2020 ◽  
Author(s):  
Hera Guðlaugsdóttir ◽  
Jesper Sjolte ◽  
Árný Erla Sveinbjörnsdóttir ◽  
Hans Christian Steen-Larsen
Keyword(s):  
Climate Variability ◽  
North Atlantic Oscillation ◽  
Atmospheric Circulation ◽  
North Atlantic ◽  
High Latitude ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract Volcanic eruptions are important drivers of climate variability on both seasonal and multi-decadal time scales as a result of atmosphere-ocean coupling. While the direct response after equatorial eruptions emerges as the positive phase of the North Atlantic Oscillation in the first two years after an eruption, less is known about high latitude northern hemisphere eruptions. In this study we assess the difference between equatorial and high latitude volcanic eruptions through the reconstructed atmospheric circulation and stable water isotope records of Greenland ice cores for the last millennia (1241-1979 CE), where the coupling mechanism behind the long-term response is addressed. The atmospheric circulation is studied through the four main modes of climate variability in the North Atlantic, the Atlantic Ridge, Scandinavian Blocking and the positive and negative phase of the North Atlantic Oscillation. We report a difference in the atmospheric circulation response after high latitude eruptions compared to the response after equatorial eruptions, where the positive phase of the North Atlantic Oscillation and the Atlantic Ridge seem to be more associated with equatorial eruptions while the negative phase of the North Atlantic Oscillation seems to follow high latitude eruptions. This response is present during the first five years and then again in years 8-12 after both equatorial and high latitude eruptions. Such a prolonged response is evidence of an ocean-atmosphere coupling that is initiated through different mechanisms, where we suspect sea ice to play a key role.

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