scholarly journals The recruitment of Atlantic salmon in Europe

2009 ◽  
Vol 66 (2) ◽  
pp. 289-304 ◽  
Author(s):  
Kevin D. Friedland ◽  
Julian C. MacLean ◽  
Lars P. Hansen ◽  
Arnaud J. Peyronnet ◽  
Lars Karlsson ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
North Atlantic ◽  
Atlantic Multidecadal Oscillation ◽  
Climate Forcing ◽  
Biological Interactions ◽  
Physical Forcing ◽  
The North ◽  
Decadal Scale ◽  
The North Atlantic Oscillation ◽  
Growth Analyses

Abstract Friedland, K. D., MacLean, J. C., Hansen, L. P., Peyronnet, A. J., Karlsson, L., Reddin, D. G., Ó Maoiléidigh, N., and McCarthy, J. L. 2009. The recruitment of Atlantic salmon in Europe. – ICES Journal of Marine Science, 66: 289–304. The stock complex of Atlantic salmon, Salmo salar, in Europe has experienced a multidecadal decline in recruitment, resulting in the lowest stock abundances observed since 1970. Here, physical forcing, biological interactions, and the resultant growth response of post-smolt salmon are examined with a view to understanding the mechanism controlling recruitment. Sea surface temperature (SST) has increased in the Northeast Atlantic, with the pattern and seasonal change in SST negatively correlated with post-smolt survival during summer and in a region that spatially matches the post-smolt nursery. Constituents of the pelagic foodweb, including potential post-smolt food and plankton that may affect post-smolt forage, have changed on a decadal scale and correlate with salmon survival. Retrospective growth analyses of eight stock/sea age components show that post-smolt growth during summer is positively correlated with salmon survival and recruitment. The Atlantic Multidecadal Oscillation appears to be a more closely aligned climate forcing index than the North Atlantic Oscillation with respect to salmon recruitment. European Atlantic salmon recruitment appears to be governed by factors that affect the growth of post-smolts during their first summer at sea, including SST and forage abundances; growth appears to mediate survival by the functional relationship between post-smolts and their predators.

scholarly journals The Central Role of Ocean Dynamics in Connecting the North Atlantic Oscillation to the Extratropical Component of the Atlantic Multidecadal Oscillation

2017 ◽  
Vol 30 (10) ◽  
pp. 3789-3805 ◽  
Author(s):  
Thomas L. Delworth ◽  
Fanrong Zeng ◽  
Liping Zhang ◽  
Rong Zhang ◽  
Gabriel A. Vecchi ◽  
...  
Keyword(s):  
Heat Flux ◽  
North Atlantic ◽  
Atlantic Multidecadal Oscillation ◽  
Ocean Dynamics ◽  
The North ◽  
Decadal Scale ◽  
The North Atlantic ◽  
Slab Ocean ◽  
The North Atlantic Oscillation ◽  
Sst Anomalies

Abstract The relationship between the North Atlantic Oscillation (NAO) and Atlantic sea surface temperature (SST) variability is investigated using models and observations. Coupled climate models are used in which the ocean component is either a fully dynamic ocean or a slab ocean with no resolved ocean heat transport. On time scales less than 10 yr, NAO variations drive a tripole pattern of SST anomalies in both observations and models. This SST pattern is a direct response of the ocean mixed layer to turbulent surface heat flux anomalies associated with the NAO. On time scales longer than 10 yr, a similar relationship exists between the NAO and the tripole pattern of SST anomalies in models with a slab ocean. A different relationship exists both for the observations and for models with a dynamic ocean. In these models, a positive (negative) NAO anomaly leads, after a decadal-scale lag, to a monopole pattern of warming (cooling) that resembles the Atlantic multidecadal oscillation (AMO), although with smaller-than-observed amplitudes of tropical SST anomalies. Ocean dynamics are critical to this decadal-scale response in the models. The simulated Atlantic meridional overturning circulation (AMOC) strengthens (weakens) in response to a prolonged positive (negative) phase of the NAO, thereby enhancing (decreasing) poleward heat transport, leading to broad-scale warming (cooling). Additional simulations are used in which heat flux anomalies derived from observed NAO variations from 1901 to 2014 are applied to the ocean component of coupled models. It is shown that ocean dynamics allow models to reproduce important aspects of the observed AMO, mainly in the Subpolar Gyre.

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.

scholarly journals Revisiting the marine migration of US Atlantic salmon using historical Carlin tag data

2012 ◽  
Vol 69 (9) ◽  
pp. 1609-1615 ◽  
Author(s):  
Alicia S. Miller ◽  
Timothy F. Sheehan ◽  
Mark D. Renkawitz ◽  
Alfred L. Meister ◽  
Timothy J. Miller
Keyword(s):  
Atlantic Salmon ◽  
New England ◽  
Additive Model ◽  
Atlantic Multidecadal Oscillation ◽  
The United States ◽  
West Greenland ◽  
The North ◽  
Marine Migration ◽  
Penobscot River ◽  
The North Atlantic Oscillation

Abstract Miller, A. S., Sheehan, T. F., Renkawitz, M. D., Meister, A. L., and Miller, T. J. 2012. Revisiting the marine migration of US Atlantic salmon using historical Carlin tag data. – ICES Journal of Marine Science, 69: 1609–1615. The development of a fishery for Atlantic salmon (Salmo salar) in the sea at West Greenland in the early 1960s prompted the start of a US tagging programme in 1962. Between 1962 and 1996, more than 1.5 million salmon from New England rivers, primarily hatchery-reared smolts, were tagged and released. Overall, the rate of tag recovery was 0.55%, with 23.2% of the tags recovered from Canada, 26.0% from Greenland, and 50.8% from the United States. A generalized additive model was used to analyse marine survival based on returns of tagged salmon to the Penobscot River. The month and year of release, sea age, smolt age, and environmental variables, such as the North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO) indices and local sea surface temperatures (SSTs), were assessed to explain the variability in the return rate. The AMO and NAO indices, SST, sea age, and time across years all affected survival assessed in terms of returns to the Penobscot River. The results provide information to support the management of Atlantic salmon stocks on a spatial and temporal scale in US rivers and the fishery at West Greenland.

scholarly journals Modelling annual mass balances of eight Scandinavian glaciers using statistical models

2015 ◽  
Vol 9 (1) ◽  
pp. 383-415 ◽  
Author(s):  
M. Trachsel ◽  
A. Nesje
Keyword(s):  
North Atlantic ◽  
Statistical Models ◽  
Atlantic Multidecadal Oscillation ◽  
Relative Importance ◽  
Mass Balances ◽  
Average Mass ◽  
The North ◽  
Nao Index ◽  
Time Period ◽  
The North Atlantic Oscillation

Abstract. Glacier mass balances are mainly influenced by accumulation-season precipitation and ablation-season temperature. We use a suite of statistical models to determine the influence of accumulation-season precipitation and ablation-season temperature on annual mass balances of eight Scandinavian glaciers, ranging from near coastal, maritime glaciers to inland, continental glaciers. Accumulation-season precipitation is more important for maritime glaciers, whereas ablation-season temperature is more important for annual balances of continental glaciers. However, the importances are not stable in time. For instance, accumulation-season precipitation is more important than ablation-season temperature for all glaciers in the 30 year period 1968–1997. In this time period the Atlantic Multidecadal Oscillation (AMO) index was consistently negative and the North Atlantic Oscillation (NAO) Index was consistently positive between 1987 and 1995, both being favourable for glacier growth. Hence, the relative importance of precipitation and temperature for mass balances is possibly influenced by the AMO and the NAO. Climate sensitivities estimated by statistical models are similar to climate sensitivities based on degree-day models, but are lower than climate sensitivities of energy balance models. Hence, future projections of mass balances found with our models seem rather optimistic. Still, all average mass balances found for the years 2050 and 2100 are negative.

scholarly journals The North Atlantic Oscillations: Cycle Times for the NAO, the AMO and the AMOC

Climate ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 43 ◽  
Author(s):  
Knut Lehre Seip ◽  
Øyvind Grøn ◽  
Hui Wang
Keyword(s):  
Time Series ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Atlantic Multidecadal Oscillation ◽  
Meridional Overturning Circulation ◽  
Cycle Times ◽  
The North ◽  
In Series ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

We show that oceanic cycle lengths persist across oceanic cyclic time-series by comparing cycles in series that come from “sister” measurements in the North Atlantic Ocean. These are the North Atlantic oscillation (NAO), the Atlantic multidecadal oscillation (AMO) and the Atlantic meridional overturning circulation (AMOC). The raw NAO series, which is an extremely noisy series in its raw format, showed cycles at 7, 13, 20, 26 and 34 years that were common with, or overlapped, the other two series, and across increasing degrees of smoothing of the NAO series. At the 1960 midpoint of the hiatus period 1943–1975, NAO was leading time-series to AMOC and AMO and AMO was a leading time-series to AMOC, but in 1975, at the end of the hiatus period, the leading relations were reversed.

scholarly journals Influence of North Atlantic climate variability on glacier mass balance in Norway, Sweden and Svalbard

2019 ◽  
Vol 65 (252) ◽  
pp. 580-594 ◽  
Author(s):  
DAVID BROOKING BONAN ◽  
JOHN ERICH CHRISTIAN ◽  
KNUT CHRISTIANSON
Keyword(s):  
Climate Variability ◽  
Mass Balance ◽  
North Atlantic ◽  
Temporal Structure ◽  
Atlantic Multidecadal Oscillation ◽  
The Arctic ◽  
Glacier Mass Balance ◽  
The North ◽  
The North Atlantic Oscillation ◽  
The Impact

ABSTRACTClimate variability can complicate efforts to interpret any long-term glacier mass-balance trends due to anthropogenic warming. Here we examine the impact of climate variability on the seasonal mass-balance records of 14 glaciers throughout Norway, Sweden and Svalbard using dynamical adjustment, a statistical method that removes orthogonal patterns of variability shared between each mass-balance record and sea-level pressure or sea-surface temperature predictor fields. For each glacier, the two leading predictor patterns explain 27–81% of the winter mass-balance variability and 24–69% of the summer mass-balance variability. The spatial and temporal structure of these patterns indicates that accumulation variability for all of the glaciers is strongly related to the North Atlantic Oscillation (NAO), with the Atlantic Multidecadal Oscillation (AMO) also modulating accumulation variability for the northernmost glaciers. Given this result, predicting glacier change in the region may depend on NAO and AMO predictability. In the raw mass-balance records, the glaciers throughout southern Norway have significantly negative summer trends, whereas the glaciers located closer to the Arctic have negative winter trends. Removing the effects of climate variability suggests it can bias trends in mass-balance records that span a few decades, but its effects on most of the longer-term mass-balance trends are minimal.

The Atlantic Multidecadal Oscillation controls the impact of the North Atlantic Oscillation on North European climate

2021 ◽  
Author(s):  
Florian Börgel ◽  
Claudia Frauen ◽  
Thomas Neumann ◽  
H. E. Markus Meier
Keyword(s):  
North America ◽  
Spatial Structure ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Atlantic Multidecadal Oscillation ◽  
The North ◽  
European Climate ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
The Impact

<p>European climate is heavily influenced by the North Atlantic Oscillation (NAO). However, the spatial structure of the NAO is varying with time, affecting its regional importance. By analyzing an 850-year global climate model simulation of the last millennium it is shown that the variations in the spatial structure of the NAO can be linked to the Atlantic Multidecadal Oscillation (AMO). The AMO changes the zonal position of the NAO centers of action, moving them closer to Europe or North America. During AMO+ states, the Icelandic Low moves further towards North America while the Azores High moves further towards Europe and vice versa for AMO- states. The results of a regional downscaling for the East Atlantic/European domain show that AMO-induced changes in the spatial structure of the NAO reduce or enhance its influence on regional climate variables of the Baltic Sea such as sea surface temperature, ice extent, or river runoff.</p>

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