scholarly journals Interannual variability of winter precipitation in the European Alps: relations with the North Atlantic Oscillation.

2009 ◽  
Vol 13 (1) ◽  
pp. 17-25 ◽  
Author(s):  
E. Bartolini ◽  
P. Claps ◽  
P. D'Odorico
Keyword(s):  
Water Resources ◽  
North Atlantic Oscillation ◽  
Interannual Variability ◽  
North Atlantic ◽  
Large Scale ◽  
Mechanistic Explanation ◽  
Winter Precipitation ◽  
The Arctic ◽  
European Alps ◽  
The Alps

Abstract. The European Alps rely on winter precipitation for various needs in terms of hydropower and other water uses. Major European rivers originate from the Alps and depend on winter precipitation and the consequent spring snow melt for their summer base flows. Understanding the fluctuations in winter rainfall in this region is crucially important to the study of changes in hydrologic regime in river basins, as well as to the management of their water resources. Despite the recognized relevance of winter precipitation to the water resources of the Alps and surrounding regions, the magnitude and mechanistic explanation of interannual precipitation variability in the Alpine region remains unclear and poorly investigated. Here we use gridded precipitation data from the CRU TS 1.2 to study the interannual variability of winter alpine precipitation. We found that the Alps are the region with the highest interannual variability in winter precipitation in Europe. This variability cannot be explained by large scale climate patterns such as the Arctic Oscillation (AO), North Atlantic Oscillation (NAO) or the East Atlantic/West Russia (EA/WR), even though regions below and above the Alps demonstrate connections with these patterns. Significant trends were detected only in small regions located in the Eastern part of the Alps.

scholarly journals Interannual variability of winter precipitation in the European Alps: relations with the North Atlantic Oscillation

2008 ◽  
Vol 5 (4) ◽  
pp. 2045-2065 ◽  
Author(s):  
E. Bartolini ◽  
P. Claps ◽  
P. D'Odorico
Keyword(s):  
Water Resources ◽  
Interannual Variability ◽  
Large Scale ◽  
Mechanistic Explanation ◽  
Winter Precipitation ◽  
European Alps ◽  
Small Areas ◽  
The North ◽  
The Alps ◽  
The North Atlantic Oscillation

Abstract. The European Alps rely on winter precipitation for various needs in terms of hydropower and other water uses. Major European rivers originate from the Alps and rely on winter precipitation and the consequent spring snow melt for their summer base flows. Understanding the fluctuations in winter rainfall in this region is crucially important to the study of changes in hydrologic regime in streams and rivers, as well as to the management of their water resources. Despite the recognized relevance of winter precipitation to the water resources of the Alps and surrounding regions, the magnitude and mechanistic explanation of interannual precipitation variability in the Alpine region remain unclear and poorly investigated. Here we use gridded precipitation data from the CRU TS 1.2 to study the interannual variability of winter alpine precipitation. We found that the Alps are the region with the highest interannual variability in winter precipitation in Europe. This variability cannot be completely explained by large scale climate patterns such as the AO, NAO or the EA-WR, even though regions below and above the Alps demonstrate connections with these patterns. Significant trends were detected only in small areas within this region, and were of opposite sign between the eastern and western part of the Alps.

scholarly journals Spatial patterns of North Atlantic Oscillation influence on mass balance variability of European Glaciers

2012 ◽  
Vol 6 (1) ◽  
pp. 1-35 ◽  
Author(s):  
B. Marzeion ◽  
A. Nesje
Keyword(s):  
North Atlantic Oscillation ◽  
Mass Balance ◽  
North Atlantic ◽  
Winter Season ◽  
Winter Precipitation ◽  
Glacier Mass Balance ◽  
European Alps ◽  
Mass Balances ◽  
Minimal Models ◽  
Temperature Anomalies

Abstract. We present and validate a set of minimal models of glacier mass balance variability. The most skillful model is then applied to reconstruct 7735 individual time series of mass balance variability for all glaciers in the European Alps and Scandinavia. Subsequently, we investigate the influence of atmospheric variability associated with the North Atlantic Oscillation (NAO) on the glaciers' mass balances. We find a spatial coherence in the glaciers' sensitivity to NAO forcing which is caused by regionally similar mechanisms relating the NAO forcing to the mass balance: In Southwestern Scandinavia, winter precipitation causes a correlation of mass balances with the NAO. In Northern Scandinavia, temperature anomalies outside the core winter season cause an anti-correlation between NAO and mass balances. In the Western Alps, both temperature and winter precipitation anomalies lead to a weak anti-correlation of mass balances with the NAO, while in the Eastern Alps, the influences of winter precipitation and temperature anomalies tend to cancel each other, and only on the southern side a slight anti-correlation of mass balances with the NAO prevails.

scholarly journals Spatial patterns of North Atlantic Oscillation influence on mass balance variability of European glaciers

2012 ◽  
Vol 6 (3) ◽  
pp. 661-673 ◽  
Author(s):  
B. Marzeion ◽  
A. Nesje
Keyword(s):  
North Atlantic Oscillation ◽  
Mass Balance ◽  
North Atlantic ◽  
Winter Season ◽  
Winter Precipitation ◽  
Glacier Mass Balance ◽  
European Alps ◽  
Mass Balances ◽  
Minimal Models ◽  
Temperature Anomalies

Abstract. We present and validate a set of minimal models of glacier mass balance variability. The most skillful model is then applied to reconstruct 7735 individual time series of mass balance variability for all glaciers in the European Alps and Scandinavia. Subsequently, we investigate the influence of atmospheric variability associated with the North Atlantic Oscillation (NAO) on the glaciers' mass balances. We find a spatial coherence in the glaciers' sensitivity to NAO forcing which is caused by regionally similar mechanisms relating the NAO forcing to the mass balance: in southwestern Scandinavia, winter precipitation causes a correlation of mass balances with the NAO. In northern Scandinavia, temperature anomalies outside the core winter season cause an anti-correlation between NAO and mass balances. In the western Alps, both temperature and winter precipitation anomalies lead to a weak anti-correlation of mass balances with the NAO, while in the eastern Alps, the influences of winter precipitation and temperature anomalies tend to cancel each other, and only on the southern side a slight anti-correlation of mass balances with the NAO prevails.

scholarly journals The Arctic Winter Sea Ice Quadrupole Revisited

2017 ◽  
Vol 30 (9) ◽  
pp. 3157-3167 ◽  
Author(s):  
S. Close ◽  
M.-N. Houssais ◽  
C. Herbaut
Keyword(s):  
Sea Ice ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Large Scale ◽  
Dominant Mode ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

The dominant mode of Arctic sea ice variability in winter is often maintained to be represented by a quadrupole structure, comprising poles of one sign in the Okhotsk, Greenland, and Barents Seas and of opposing sign in the Labrador and Bering Seas, forced by the North Atlantic Oscillation. This study revisits this large-scale winter mode of sea ice variability using microwave satellite and reanalysis data. It is found that the quadrupole structure does not describe a significant covariance relationship among all four component poles. The first empirical orthogonal mode, explaining covariability in the sea ice of the Barents, Greenland, and Okhotsk Seas, is linked to the Siberian high, while the North Atlantic Oscillation only exhibits a significant relationship with the Labrador Sea ice, which varies independently as the second mode. The principal components are characterized by a strong low-frequency signal; because the satellite record is still short, these results suggest that statistical analyses should be applied cautiously.

North Atlantic Oscillation; a Climatic Indicator to Predict Hydropower Availability in Scandinavia

2002 ◽  
Vol 33 (5) ◽  
pp. 415-424 ◽  
Author(s):  
Cintia B. Uvo ◽  
Ronny Berndtsson
Keyword(s):  
Climate Change ◽  
Spatial Distribution ◽  
Climate Variability ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Winter Precipitation ◽  
Model Driven ◽  
The World ◽  
Hydropower Production ◽  
Precipitation And Temperature

Climate variability and climate change are of great concern to economists and energy producers as well as environmentalists as both affect the precipitation and temperature in many regions of the world. Among those affected by climate variability is the Scandinavian Peninsula. Particularly, its winter precipitation and temperature are affected by the variations of the so-called North Atlantic Oscillation (NAO). The objective of this paper is to analyze the spatial distribution of the influence of NAO over Scandinavia. This analysis is a first step to establishing a predictive model, driven by a climatic indicator such as NAO, for the available water resources of different regions in Scandinavia. Such a tool would be valuable for predicting potential of hydropower production one or more seasons in advance.

scholarly journals The Evolutionary History, Diversity, and Ecology of Willows (Salix L.) in the European Alps

Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 146
Author(s):  
Natascha D. Wagner ◽  
Li He ◽  
Elvira Hörandl
Keyword(s):  
Habitat Preferences ◽  
Introgressive Hybridization ◽  
Ecological Factors ◽  
The Arctic ◽  
Secondary Contact ◽  
European Alps ◽  
Climatic Fluctuations ◽  
History Of ◽  
European Mountain ◽  
The Alps

The genus Salix (willows), with 33 species, represents the most diverse genus of woody plants in the European Alps. Many species dominate subalpine and alpine types of vegetation. Despite a long history of research on willows, the evolutionary and ecological factors for this species richness are poorly known. Here we will review recent progress in research on phylogenetic relationships, evolution, ecology, and speciation in alpine willows. Phylogenomic reconstructions suggest multiple colonization of the Alps, probably from the late Miocene onward, and reject hypotheses of a single radiation. Relatives occur in the Arctic and in temperate Eurasia. Most species are widespread in the European mountain systems or in the European lowlands. Within the Alps, species differ ecologically according to different elevational zones and habitat preferences. Homoploid hybridization is a frequent process in willows and happens mostly after climatic fluctuations and secondary contact. Breakdown of the ecological crossing barriers of species is followed by introgressive hybridization. Polyploidy is an important speciation mechanism, as 40% of species are polyploid, including the four endemic species of the Alps. Phylogenomic data suggest an allopolyploid origin for all taxa analyzed so far. Further studies are needed to specifically analyze biogeographical history, character evolution, and genome evolution of polyploids.

scholarly journals The Interannual Variability of the Haines Index over North America

2013 ◽  
Vol 52 (11) ◽  
pp. 2396-2409 ◽  
Author(s):  
Lejiang Yu ◽  
Shiyuan Zhong ◽  
Xindi Bian ◽  
Warren E. Heilman ◽  
Joseph J. Charney
Keyword(s):  
United States ◽  
Pacific Ocean ◽  
North America ◽  
Interannual Variability ◽  
Large Scale ◽  
Southern Oscillation ◽  
Southeastern United States ◽  
Lower Atmosphere ◽  
The Arctic ◽  
Fire Weather Index

AbstractThe Haines index (HI) is a fire-weather index that is widely used as an indicator of the potential for dry, low-static-stability air in the lower atmosphere to contribute to erratic fire behavior or large fire growth. This study examines the interannual variability of HI over North America and its relationship to indicators of large-scale circulation anomalies. The results show that the first three HI empirical orthogonal function modes are related respectively to El Niño–Southern Oscillation (ENSO), the Arctic Oscillation (AO), and the interdecadal sea surface temperature variation over the tropical Pacific Ocean. During the negative ENSO phase, an anomalous ridge (trough) is evident over the western (eastern) United States, with warm/dry weather and more days with high HI values in the western and southeastern United States. During the negative phase of the AO, an anomalous trough is found over the western United States, with wet/cool weather and fewer days with high HI, while an anomalous ridge occurs over the southern United States–northern Mexico, with an increase in the number of days with high HI. After the early 1990s, the subtropical high over the eastern Pacific Ocean and the Bermuda high were strengthened by a wave train that was excited over the tropical western Pacific Ocean and resulted in warm/dry conditions over the southwestern United States and western Mexico and wet weather in the southeastern United States. The above conditions are reversed during the positive phase of ENSO and AO and before the early 1990s.

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