Atmosphere–Ocean Coupling in the Northern Gulf of St. Lawrence: Frequency-Dependent Wind-Forced Variations in Nearshore Sea Temperatures and Currents

1988 ◽  
Vol 45 (7) ◽  
pp. 1222-1233 ◽  
Author(s):  
G. A. Rose ◽  
W. C. Leggett
Keyword(s):  
Time Domain ◽  
Domain Model ◽  
Fish Migration ◽  
Biological Processes ◽  
Frequency Dependent ◽  
Sea Temperature ◽  
Temperature Changes ◽  
North Shore ◽  
The North ◽  
Ocean Coupling

We found nearshore sea temperatures and currents on the north shore of the Gulf of St. Lawrence to be linked to wind-forced upwellings and downwellings. Multiple coherence of alongshore and cross-shore wind stresses with sea temperature (f > 1/d removed) was significant at periods > 3 d (maximum K2 = 0.90) and at 1.8 d. Partial coherences were frequency dependent. At periods > 3 d, which contained most of the variance alongshore forces dominated. Cross-shore winds were significant only at 1.8 d. A time domain model using lagged wind stress and cumulative air temperature as predictors explained 95% of the variance in post-stratification nearshore temperature. Temperature changes were virtually synchronous along 150 km of coastline. Alongshore currents were coherent with alongshore winds at periods > 2 d. Cross-shore currents were coherent with cross-shore winds at periods of 1–2 d. These results are compared with Csanady's models of wind-forced coastal thermocline oscillation. We conclude that alongshore winds force major upwellings and downwellings in this region. Cross-shore forces are important at f > 0.5/d. These dynamics regulate local primary biological processes and the transport of energy through their influence on fish migration.

Atmosphere–Ocean Coupling and Atlantic Cod Migrations: Effect of Wind-Forced Variations in Sea Temperatures and Currents or Nearshore Distributions and Catch Rates of Gadus morhua

1988 ◽  
Vol 45 (7) ◽  
pp. 1234-1243 ◽  
Author(s):  
G. A. Rose ◽  
W. C. Leggett
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Analysis Model ◽  
Sea Temperature ◽  
The North ◽  
Dual Beam ◽  
Ocean Coupling ◽  
Catch Rates ◽  
Alongshore Wind

Coastal upwellings and downwellings forced by alongshore winds on the north shore of the Gulf of St. Lawrence were associated with variability in onshore movements and inshore daily catches of Atlantic cod (Gadus morhua). Mean cod densities in the zone offshore from the trap sites, determined by hydroacoustic integration scaled by an in situ dual beam determined mean backscatter, ranged from 2.6 to 82.7 fish/105 m3. Cod were located where sea temperatures ranged from −0.5 to 8.5 °C. Catches were nil where temperatures were outside this range. Cod were located at depths which correlated with the strength of alongshore currents (r = −0.55). A path analysis model with predictors alongshore wind stress and current, sea temperature, and cod density accounted for 76% of the variance in catch. Cod abundance in the offshore zone accounted for the most variance independent of other factors (27%). Sea temperature and currents accounted for 15 and 13%, respectively. Peaks in catch (to 1500 kg/d) coincided with maximum rates of decline in sea temperatures and with NE upwelling currents. Low catches coincided with maximum rates of increase in temperatures and with SW currents. In a regression model, four lags of alongshore wind accounted for 83% of the variance in catch.

Efficient Time-Domain Model for Frequency-Dependent Added Mass and Damping

2004 ◽  
Author(s):  
Karl Erik Kaasen ◽  
Knut Mo
Keyword(s):  
Differential Equation ◽  
Time Domain ◽  
Mass Function ◽  
Added Mass ◽  
Domain Model ◽  
Frequency Dependent ◽  
Induced Motion ◽  
Linear Differential ◽  
Wave Induced ◽  
Velocity History

In simulation of 1st-order wave-induced motion of vessels it is sometimes necessary to express frequency-dependent added mass and damping in time-domain formulation. One way to do this is to transform the frequency dependence into retardation functions. During simulation these are convolved with the velocity history, which is time-consuming and impractical. To get a more efficient model a method for expressing the retardation function as a linear differential equation has been developed. The method calculates the coefficients of the differential equation from the damping function only, avoiding the uncertain added mass function.

The distribution of benthic hydrographic indicator species in Svalbard waters, 1978–1981

1984 ◽  
Vol 64 (3) ◽  
pp. 667-677 ◽  
Author(s):  
M. F. Dyer ◽  
G. J. Cranmer ◽  
P. D. Fry ◽  
W. G. Fry
Keyword(s):  
Considerable Change ◽  
Turn Of The Century ◽  
The Arctic ◽  
Past Century ◽  
Sea Temperature ◽  
Temperature Changes ◽  
The North ◽  
Arctic Regions ◽  
Temperature Ranges ◽  
The Mean

Fourteen species of benthic invertebrates, found to be indicators of hydrographic conditions by Blacker (1957), were recorded during research cruises between Finmark and north Spitsbergen during the summers of 1978, 1979, 1980 and 1981. The distributions were compared with those found during surveys carried out between 1949 and 1959.Both Atlantic and Arctic species were found to the north of Bear Island and along the west coast of Spitsbergen, and the temperature ranges at which they were found were greater than those found by Blacker (1957).IntroductionDuring the past century the annual mean temperature of the Arctic regions has undergone a considerable change. The warming of the regions began about 1885 (Willett, 1950) and peaked around 1938, when the mean air temperature of Spitsbergen was nearly 6 °C warmer than at the turn of the century (Hoel, 1953). The warming of the seas in the region seems to have started later - Jensen (1939) suggests 1917 - and sea temperature changes were detected north of Spitsbergen in 1921 (Schokalsky, 1936). This warming resulted in the reappearance of cod in great quantities on the Bear Island Bank, after the absence of any sustained quantities for about 40 years (Blacker, 1957).The marine benthos of Svalbardf was surveyed during the latter part of the last century and the first half of this century (1878–1914,1923–31) when the benthos was recorded during several cruises in the region (see Blacker (1957) for review). The benthos was again recorded between 1949 and 1955 (Blacker, 1957) and 1955 and 1959 (Blacker, 1965); see Fig. lA.

On Riccia marginata and related species (Ricciaceae, Marchantiophyta)

2012 ◽  
Vol 46 ◽  
pp. 298-305 ◽  
Author(s):  
A. D. Potemkin ◽  
T. Ahti
Keyword(s):  
Related Species ◽  
Lake Ladoga ◽  
Leningrad Region ◽  
Sem Images ◽  
North Shore ◽  
The North ◽  
Molecular Studies ◽  
The Future ◽  
The Town

Riccia marginata Lindb. was described by S. O. Lindberg (1877) from the outskirts of the town of Sortavala near the north shore of Lake Ladoga, Republic of Karelia, Russia. The species has been forgotten in most recent liverwort accounts of Europe, including Russia. Lectotypification of R. marginata is provided. R. marginata shares most characters with R. beyrichiana Hampe ex Lehm. It differs from “typical” plants of R. beyrichiana in having smaller spores, with ± distinctly finely areolate to roughly papillose proximal surfaces and a narrower and shorter thallus, as well as in scarcity or absence of marginal hairs. It may represent continental populations of the suboceanic-submediterranean R. beyrichiana, known in Russia from the Leningrad Region and Karelia only. The variability of spore surfaces in R. beyrichiana is discussed and illustrated by SEM images. A comparison with the spores of R. bifurca Hoffm. is provided. The question how distinct R. marginata is from R. beyrichiana needs to be clarified by molecular studies in the future, when adequate material is available. R. marginata is for the time being, provisionally, included in R. beyrichiana.

Conflict, Population Movement, and Microscale Social Networks in Northern Iroquoian Archaeology

2021 ◽  
Vol 86 (2) ◽  
pp. 350-367
Author(s):  
Jennifer Birch ◽  
John P. Hart
Keyword(s):  
Social Networks ◽  
Sixteenth Century ◽  
Lake Ontario ◽  
Population Movement ◽  
Network Ties ◽  
The West ◽  
Local Networks ◽  
North Shore ◽  
The North ◽  
Specific Sequences

We employ social network analysis of collar decoration on Iroquoian vessels to conduct a multiscalar analysis of signaling practices among ancestral Huron-Wendat communities on the north shore of Lake Ontario. Our analysis focuses on the microscale of the West Duffins Creek community relocation sequence as well as the mesoscale, incorporating several populations to the west. The data demonstrate that network ties were stronger among populations in adjacent drainages as opposed to within drainage-specific sequences, providing evidence for west-to-east population movement, especially as conflict between Wendat and Haudenosaunee populations escalated in the sixteenth century. These results suggest that although coalescence may have initially involved the incorporation of peoples from microscale (local) networks, populations originating among wider mesoscale (subregional) networks contributed to later coalescent communities. These findings challenge previous models of village relocation and settlement aggregation that oversimplified these processes.

Sign in / Sign up

Export Citation Format

Share Document