scholarly journals Population structure and spatial distribution of porbeagles (Lamna nasus) in Irish waters

2019 ◽  
Vol 76 (6) ◽  
pp. 1581-1590 ◽  
Author(s):  
Luke W J Cameron ◽  
William K Roche ◽  
Jonathan D R Houghton ◽  
Paul J Mensink
Keyword(s):  
Population Structure ◽  
Spatial Distribution ◽  
North Atlantic ◽  
Population Decline ◽  
The North ◽  
Aggregation Site ◽  
Show Evidence ◽  
Long Term Trends ◽  
Almost All

Abstract Porbeagles throughout the North Atlantic have experienced severe population decline through overfishing, with the northeastern population listed as critically endangered. Management of this population is constrained by the paucity of data on porbeagle population structure, distribution and behaviour in this region. Here we use a long-term (47 year) Irish capture-mark-recapture dataset to investigate the population structure, spatial distribution and seasonal movements of this species. From 1970–2017, a total of 268 sharks (9 recaptures) were ID tagged, with most individuals likely being juvenile based on length at maturity estimates (mean total length = 143.9 cm, SD = 35.4). Almost all captures were recorded at three distinct locations near angling hubs along the south, west and north coasts with catches peaking in August. Long-term trends in capture date indicated a shift towards earlier capture dates in the northern site (n = 153). Our findings suggest Irish waters may act as a persistent summer aggregation site for juveniles, which show evidence for seasonal site fidelity, returning to nearby locations between years. These findings demonstrate the utility of such programmes, which can be implemented, with minimal expense by engaging with the angling sector, to elucidate the population structure and distribution of wide-ranging fish species.

scholarly journals On the ability of statistical wind-wave models to capture the variability and long-term trends of the North Atlantic winter wave climate

2016 ◽  
Vol 103 ◽  
pp. 177-189 ◽  
Author(s):  
Adrián Martínez-Asensio ◽  
Marta Marcos ◽  
Michael N. Tsimplis ◽  
Gabriel Jordà ◽  
Xiangbo Feng ◽  
...  
Keyword(s):  
North Atlantic ◽  
Wind Wave ◽  
Wave Climate ◽  
The North ◽  
Long Term Trends ◽  
The North Atlantic ◽  
Wave Models

scholarly journals A twenty-year study on natural and manmade global interannual fluctuations of cirrus cloud cover

2007 ◽  
Vol 7 (1) ◽  
pp. 93-126 ◽  
Author(s):  
K. Eleftheratos ◽  
C. S. Zerefos ◽  
P. Zanis ◽  
D. S. Balis ◽  
G. Tselioudis ◽  
...  
Keyword(s):  
Relative Humidity ◽  
North Atlantic ◽  
Annual Cycle ◽  
Cloud Cover ◽  
Cirrus Cloud ◽  
The North ◽  
Long Term Trends ◽  
The North Atlantic ◽  
The Tropics

Abstract. The seasonal variability and the interannual variance explained by ENSO and NAO to cirrus cloud cover (CCC) are examined during the twenty-year period 1984–2004. CCC was found to be significantly correlated with vertical velocities and relative humidity from ECMWF/ERA40 in the tropics (correlations up to –0.7 and +0.7 at some locations, respectively) suggesting that variations in large-scale vertical winds and relative humidity fields can be the origin of up to half of the local variability in CCC over these regions. These correlations reflect mostly the seasonal cycle. Although the annual cycle is dominant in all latitudes and longitudes, peaking over the tropics and subtropics, its amplitude can be exceeded during strong El Nino/La Nina events. Over the eastern tropical Pacific Ocean the interannual variance of CCC which can be explained by ENSO is about 6.8% and it is ~2.3 times larger than the amplitude of the annual cycle. Natural long-term trends in the tropics are generally small (about –0.3% cloud cover per decade) and possible manmade trends in those regions are also small. The contributions of NAO and QBO to the variance of CCC in the tropics are also small. In the northern mid–latitudes, on the other hand, the effect of NAO is more significant and can be very important regionally. Over northern Europe and the eastern part of the North Atlantic Flight Corridor (NAFC) there is a small positive correlation between CCC and NAO index during the wintertime of about 0.3. In this region, the interannual variance of CCC explained by NAO is 2.6% and the amplitude of the annual cycle is 3.1%. Long-term trends over this region are about +1.6% cloud cover per decade and compare well with the observed manmade trends over congested air traffic regions in Europe and the North Atlantic as have been evidenced from earlier findings.

scholarly journals A study on natural and manmade global interannual fluctuations of cirrus cloud cover for the period 1984–2004

2007 ◽  
Vol 7 (10) ◽  
pp. 2631-2642 ◽  
Author(s):  
K. Eleftheratos ◽  
C. S. Zerefos ◽  
P. Zanis ◽  
D. S. Balis ◽  
G. Tselioudis ◽  
...  
Keyword(s):  
Relative Humidity ◽  
North Atlantic ◽  
Annual Cycle ◽  
Cloud Cover ◽  
Cirrus Cloud ◽  
The North ◽  
Long Term Trends ◽  
The North Atlantic ◽  
The Tropics

Abstract. The seasonal variability and the interannual variance explained by ENSO and NAO to cirrus cloud cover (CCC) are examined during the twenty-year period 1984–2004. CCC was found to be significantly correlated with vertical velocities and relative humidity from ECMWF/ERA40 in the tropics (correlations up to −0.7 and +0.7 at some locations, respectively) suggesting that variations in large-scale vertical winds and relative humidity fields can be the origin of up to half of the local variability in CCC over these regions. These correlations reflect mostly the seasonal cycle. Although the annual cycle is dominant in all latitudes and longitudes, peaking over the tropics and subtropics, its amplitude can be exceeded during strong El Nino/La Nina events. Over the eastern tropical Pacific Ocean the interannual variance of CCC which can be explained by ENSO is about 6.8% and it is ~2.3 times larger than the amplitude of the annual cycle. Natural long-term trends in the tropics are generally small (about −0.3% cloud cover per decade) and possible manmade trends in those regions are also small. The contributions of NAO and QBO to the variance of CCC in the tropics are also small. In the northern mid-latitudes, on the other hand, the effect of NAO is more significant and can be very important regionally. Over northern Europe and the eastern part of the North Atlantic Flight Corridor (NAFC) there is a small positive correlation between CCC and NAO index during the wintertime of about 0.3. In this region, the interannual variance of CCC explained by NAO is 2.6% and the amplitude of the annual cycle is 3.1%. Long-term trends over this region are about +1.6% cloud cover per decade and compare well with the observed manmade trends over congested air traffic regions in Europe and the North Atlantic as have been evidenced from earlier findings.

scholarly journals An Analysis of the 8.85- and 4.42-Year Cycles in the Gulf of Maine

2021 ◽  
Vol 9 (12) ◽  
pp. 1362
Author(s):  
Xiaolong Zong ◽  
Ruzhen Zhang ◽  
Shuwen Zhang ◽  
Fangjing Deng ◽  
Wei Zhou ◽  
...  
Keyword(s):  
North Atlantic ◽  
Gulf Of Maine ◽  
North Atlantic Ocean ◽  
Analysis Method ◽  
Tide Gauges ◽  
The North ◽  
Point Scheme ◽  
Harmonic Analysis Method ◽  
Long Term Trends

In the background of global warming and climate change, nuisance flooding is only caused by astronomical tides, which could be modulated by the nodal cycle. Therefore, much attention should be paid to the variation in the amplitude of the nodal cycle. In this paper, we utilize the enhanced harmonic analysis method and the independent point scheme to obtain the time-dependent amplitudes of the 8.85-year cycle of N2 tide and the 4.42-year cycle of 2N2 tide based on water level records of four tide gauges in the Gulf of Maine. Results indicate that the long-term trends of N2 and 2N2 tides vary spatially, which may be affected by the sea-level rise, coastal defenses, and other possible climate-related mechanisms. The comparison between Halifax and Eastport reveals that the topography greatly influences the amplitudes of those cycles. Moreover, a quasi 20-year oscillation is obvious in the 8.85-year cycle of N2 tide. This oscillation probably relates to a 20-year mode in the North Atlantic Ocean.

scholarly journals Mean Sea Level Variability and Influence of the North Atlantic Oscillation on Long-Term Trends in the German Bight

Water ◽  
2012 ◽  
Vol 4 (1) ◽  
pp. 170-195 ◽  
Author(s):  
Sönke Dangendorf ◽  
Thomas Wahl ◽  
Hartmut Hein ◽  
Jürgen Jensen ◽  
Stephan Mai ◽  
...  
Keyword(s):  
Sea Level ◽  
North Atlantic ◽  
German Bight ◽  
Mean Sea Level ◽  
The North ◽  
Long Term Trends ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
Mean Sea Level Variability

Images of the Adversary: NATO Assessments of the Soviet Union, 1953–1964

2009 ◽  
Vol 11 (2) ◽  
pp. 89-116
Author(s):  
Evanthis Hatzivassiliou
Keyword(s):  
Soviet Union ◽  
North Atlantic ◽  
Study Groups ◽  
Military Force ◽  
The North ◽  
Nikita Khrushchev ◽  
The Soviet Union ◽  
Long Term Trends ◽  
Set Up

The article presents the analysis of the study groups set up by the North Atlantic Treaty Organization (NATO) to assess the non-military aspects of Soviet power and potential during the era of Nikita Khrushchev. Following Stalin's death, the Western alliance tried to form a comprehensive view of the strengths and weaknesses of the USSR's economy and political system. This was part of NATO's effort to adjust to the realities of a long Cold War, the outcome of which would not be decided by military force alone. The NATO reports were largely successful in describing the long-term trends of the Soviet economy and the weaknesses of the Soviet system. However, they usually failed to anticipate specific, though significant and potentially dangerous, initiatives of the Soviet regime. On balance they were a crucial input for NATO ministers, and their importance in the shaping of Western policies needs to be evaluated carefully.

Long-term population size of the North Atlantic humpback whale within the context of worldwide population structure

2012 ◽  
Vol 14 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Kristen Ruegg ◽  
Howard C. Rosenbaum ◽  
Eric C. Anderson ◽  
Marcia Engel ◽  
Anna Rothschild ◽  
...  
Keyword(s):  
Population Structure ◽  
Population Size ◽  
North Atlantic ◽  
Humpback Whale ◽  
The North ◽  
Worldwide Population ◽  
The North Atlantic

scholarly journals An Objective Satellite-Based Tropical Cyclone Size Climatology

2014 ◽  
Vol 27 (1) ◽  
pp. 455-476 ◽  
Author(s):  
John A. Knaff ◽  
Scott P. Longmore ◽  
Debra A. Molenar
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Historical Record ◽  
Maximum Intensity ◽  
Low Level ◽  
The North ◽  
Tangential Wind ◽  
Long Term Trends ◽  
The Individual

Abstract Storm-centered infrared (IR) imagery of tropical cyclones (TCs) is related to the 850-hPa mean tangential wind at a radius of 500 km (V500) calculated from 6-hourly global numerical analyses for North Atlantic and eastern North Pacific TCs for 1995–2011. V500 estimates are scaled using the climatological vortex decay rate beyond 500 km to estimate the radius of 5 kt (1 kt = 0.514 m s−1) winds (R5) or TC size. A much larger historical record of TC-centered IR imagery (1978–2011) is then used to estimate TC sizes and form a global TC size climatology. The basin-specific distributions of TC size reveal that, among other things, the eastern North Pacific TC basins have the smallest while western North Pacific have the largest TC size distributions. The life cycle of TC sizes with respect to maximum intensity shows that TC growth characteristics are different among the individual TC basins, with the North Atlantic composites showing continued growth after maximum intensity. Small TCs are generally located at lower latitudes, westward steering, and preferred in seasons when environmental low-level vorticity is suppressed. Large TCs are generally located at higher latitudes, poleward steering, and preferred in enhanced low-level vorticity environments. Postmaximum intensity growth of TCs occurs in regions associated with enhanced baroclinicity and TC recurvature, while those that do not grow much are associated with west movement, erratic storm tracks, and landfall at or near the time of maximum intensity. With respect to climate change, no significant long-term trends are found in the dataset of TC size.

Long-Term Trends of Air Temperature Changes in Industrial and Economic Centres of North-Western and Central Federal Districts of Russia and Their Causes

2017 ◽  
Vol 21 (3) ◽  
pp. 56-63
Author(s):  
V.V. Drozdov ◽  
A.V. Kosenko
Keyword(s):  
Air Temperature ◽  
North Atlantic ◽  
Federal District ◽  
Winter Period ◽  
North West ◽  
The North ◽  
Federal Districts ◽  
Long Term Trends ◽  
The Impact

Carried out the review and analysis of long-term variability of mean annual and mean during winter temperature in 13 major administrative and industrial centers of the North-West and Central federal district – Murmansk, Arkhangelsk, Petrozavodsk, St. Petersburg, Pskov, Novgorod, Kaliningrad, Moscow, Smolensk, Tambov, Kostroma, Kursk and Voronezh. On the basis of the method of cluster analysis identified the major regional characteristics variability in air temperature. An assessment of the correlation between the dynamics of the 4 values of climatic indices of atmospheric circulation over the North Atlantic – NAO (North Atlantic Oscillation) and long-term changes in air temperature. Identified and analyzed interannual trends cooling trend over the winter period. Presented a preliminary assessment of the intensity of the impact of changes in temperature conditions on industry and the economy of the North-West and central federal districts in relation to a possible cooling.

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