The generation of waves by wind

1952 ◽  
Vol 215 (1122) ◽  
pp. 299-328 ◽  
Keyword(s):  
Ocean Waves ◽  
Irish Sea ◽  
North Coast ◽  
Empirical Relationships ◽  
The North ◽  
Component Wave ◽  
Wave Trains ◽  
The Irish Sea ◽  
The Waves ◽  
Group Velocities

This paper describes an investigation of the height and length of ocean waves and swell in relation to the strength, extent and duration of the wind in the generating area, and the subsequent travel of the swell through calm and disturbed water. The investigation is based on records of waves made on the north coast of Cornwall, in the Irish Sea and in Lough Neagh. It is a practical continuation of the work of Barber & Ursell (1948), who showed that the waves leaving the generating area behave as a continuous spectrum of component wave trains which travel independently with the group velocities appropriate to their periods. The spectral distribution of energy in the storm area is considered, and the relative amplitudes of the different components are deduced empirically under various wind conditions. The results indicate that the wave characteristics become practically independent of fetch after 200 to 300 miles, and that in the equilibrium condition the steepness of the highest waves is inversely proportional to the square root of the wind speed. Some theoretical foundation can be found for the form of the empirical relationships if it is assumed that the wind acts on each wave component independently, and that the sheltering coefficient used by Jeffreys is proportional to the wave steepness. The results provide a basis for making reasonably accurate predictions of waves and swell from meteorological charts and forecasts.

The Spread of Elminius Modestus Darwin In North-West Europe

1958 ◽  
Vol 37 (2) ◽  
pp. 483-520 ◽  
Author(s):  
D. J. Crisp
Keyword(s):  
East Coast ◽  
Irish Sea ◽  
North Coast ◽  
Long Distance ◽  
North West ◽  
The North ◽  
Competition For Space ◽  
South East England ◽  
The Irish Sea ◽  
Balanus Balanoides

Material collected prior to 1940 indicates that Elminius modestus was not present on British coasts at that time.Elminius increased in abundance in south-east England from 1946 to 1950 and extended its range as far as the Humber, where it halted.Its advance westwards along the south coast was similarly halted at Portland, but by 1948 independent colonies had been established in several of the river systems of Devon and Cornwall, in Milford Haven, and in the Bristol Channel.The first populations in the Irish Sea were in Morecambe Bay. From there Elminius spread rapidly south and west along the north coast of Wales, and more slowly north and west towards Galloway, eventually bridging the sea to the Isle of Man.Detailed observations showed that Elminius advanced along the uniformly favourable north coast of Wales as a definite front moving at a rate of approximately 20–30 km per year. Around Anglesey where tidal currents were stronger it appeared simultaneously in many scattered centres.A distinction is drawn between marginal dispersal taking place under the influence of normal agencies at the boundary of an existing population, and remote dispersal due to an artificial or freak transport over a long distance. In the case of Elminius the maximum distance that is likely to be bridged by marginal dispersal in the absence of strong residual drifts is about 30 miles.Elminius probably first appeared near Southampton, and was introduced into the Thames estuary area probably by remote dispersal. Thence it spread along the east coast and was transported to Holland. Its extension into south Devon, the Bristol Channel, the Irish Sea, and to the French coast must also be attributed to remote dispersal.The main ecological effects of Elminius result from competition for space with Balanus balanoides. Since Elminius breeds in summer, its dominance has a profound effect on the composition of the summer plankton, greatly increasing the number of barnacle nauplii, presumably at the expense of other larvae.

scholarly journals NOTES ON THE GENERATION AND GROWTH OF OCEAN WAVES UNDER WIND ACTION

2000 ◽  
Vol 1 (3) ◽  
pp. 7
Author(s):  
Gerhard Neumann
Keyword(s):  
Energy Dissipation ◽  
Energy Supply ◽  
Basic Problem ◽  
Ocean Waves ◽  
Wind Action ◽  
Wave Development ◽  
Component Wave ◽  
Wave Trains ◽  
Physical Laws ◽  
The Waves

The basic problem of forecasting wind-generated waves is the development of equations which express the energy budget between wind and waves, and the derivation of physical laws governing the growth of the component wave trains. The waves can grow only in the case where the supply of energy by wind exceeds the loss of energy by friction and turbulence. Thus any attempt to calculate the growth of ocean waves under wind action requires a knowledge of the energy supply and the energy dissipation in every phase of wave development.

The medieval cultures of the Irish sea and the North Sea: Manannan and his neighbors [Book Review]

2019 ◽  
Vol 15 ◽  
pp. 142-144
Author(s):  
John Kennedy
Keyword(s):  
North Sea ◽  
Irish Sea ◽  
The North ◽  
The North Sea ◽  
The Irish Sea

Review(s) of: The medieval cultures of the Irish sea and the North Sea: Manannan and his neighbors, by MacQuarrie, Charles W., and Nagy, Joseph Falaky Nagy (eds), (Amsterdam: Amsterdam University Press, 2019) hardcover, 212 pages, 1 map, 4 figures, RRP euro99; ISBN 9789462989399.

A detailed comparison of measured and modeled wind-driven currents in the North Channel of the Irish Sea

2001 ◽  
Vol 106 (C9) ◽  
pp. 19683-19713 ◽  
Author(s):  
Alan M. Davies ◽  
Philip Hall ◽  
M. John Howarth ◽  
Philip Knight ◽  
Rose Player
Keyword(s):  
Detailed Comparison ◽  
Irish Sea ◽  
The North ◽  
The Irish Sea ◽  
Wind Driven Currents

III.—On Drift

1874 ◽  
Vol 1 (11) ◽  
pp. 496-510 ◽  
Author(s):  
J. G. Goodchild
Keyword(s):  
Ice Sheet ◽  
Irish Sea ◽  
Glacial Deposits ◽  
The North ◽  
The Irish Sea

In a letter to Nature for 14th May, 1874, Mr. Belt has expressed his belief that the presence of shells in glacial deposits, at whatever elevation they may be found, does not necessarily constitute a proof that the land has been depressed to that extent relatively to the level of the sea; but that in such cases as those of the drifts of the basin of the Irish Sea the shells occur in their present positions because they were thrust thither out of the bed of the sea by the ice-sheet which was advancing from the North.

XI.—The Glaciation of Holyhead Mountain

1904 ◽  
Vol 1 (10) ◽  
pp. 504-505
Author(s):  
Edward Greenly
Keyword(s):  
Irish Sea ◽  
General Level ◽  
The South ◽  
The West ◽  
Scottish Highlands ◽  
The North ◽  
The Irish Sea ◽  
North And South ◽  
Sea Cliffs

The bare and rocky hill known as Holyhead Mountain is of considerable interest in connection with recent geological events, standing as it does some thirty miles out from the highlands of Carnarvonshire into the Irish Sea Basin; and in such remarkable isolation, for it is much the highest of the five hills which rise above the general level of the platform of Anglesey.Its height is only 721 feet, but so strongly featured is it, especially towards the west, that one feels the term ‘mountain’ to be no misnomer, and can hardly believe it to be really lower than many of our smooth wolds and downs of Oolite and Chalk. Being composed, moreover, of white quartzite (or more properly of quartzite-schist), and being so bare of vegetation, it recalls much more vividly certain types of scenery in the Scottish Highlands than anything in those Welsh mountains that one sees from its sides. Towards the east it slopes at a moderate angle, but a little west of the summit it is traversed by a very strong feature, due to a fault, running nearly north and south, along which is a line of great crags, facing west, and prolonged northwards into the still greater sea cliffs towards the North Stack. Beyond this the land still remains high, but is smoother in outline, a somewhat softer series of rocks extending from the fault to the South Stack, where the high moors end off in great cliffs above the sea.

scholarly journals A Note on the Water Movements in the English Channel and Neighbouring Seas, considered on the Basis of Salinity Distribution.

1925 ◽  
Vol 13 (3) ◽  
pp. 670-672 ◽  
Author(s):  
J. R. Lumby
Keyword(s):  
Sea Water ◽  
Water Movement ◽  
Atlantic Water ◽  
Irish Sea ◽  
English Channel ◽  
Southern Bight ◽  
The North ◽  
The North Sea ◽  
Normal Water ◽  
The Irish Sea

Comparison of the conceptions which have hitherto been held in regard to the hydrography of the English Channel with those which are offered as a result of the recent activities of the Atlantic Slope Committee, shows that a difference exists which, in the writer's opinion, lies in the interpretation of the material, rather than in the fundamental differences in the material itself. For example, it is stated that the physical character of the water in the English Channel is conditioned, especially in the summer months, by that of the North Sea water rather than by that of the Atlantic water. “En plein été, en août, les eaux chaudes de la mer du Nord affluent dans la Manche.” A similar regimen is suggested for the waters of the Irish Sea, which are said to be derived from the northward. Carruthers shows that the normal water movement in the eastern part of the English Channel is through Dover Straits into the Southern Bight, this movement appearing to be more persistent along the bottom than on the surface. Furthermore, one of the two months in which reversal of this direction appears least likely to occur is August.

scholarly journals Age composition, growth, movements, meristics and parasites of the whiting, Merlangius merlangus, in the Severn Estuary and Bristol Channel

1988 ◽  
Vol 68 (2) ◽  
pp. 295-313 ◽  
Author(s):  
I. C. Potter ◽  
D. C. Gardner ◽  
P. N. Claridge
Keyword(s):  
Irish Sea ◽  
Age Composition ◽  
Severn Estuary ◽  
Main Site ◽  
The North ◽  
The North Sea ◽  
Inshore Waters ◽  
Merlangius Merlangus ◽  
The Irish Sea ◽  
Copepod Parasites

Samples collected from power station intake screens between 1972 and 1977 have been used to study aspects of the biology of the whiting in the Severn Estuary and Bristol Channel. 0+ whiting generally started appearing in the inner estuary in July, at which time their standard length was at least 38 mm. Their numbers peaked in October and subsequently declined particularly rapidly during the wet winter of 1976/7 when salinities were frequently below 10‰. The size of 0+ whiting in the late autumn and early winter was generally less in the shallows of the Inner Severn Estuary than in neighbouring deeper waters and in the Inner Bristol Channel. Growth rates of 0 + whiting fell within the range of those recorded for the North Sea, but below those generally found in inshore waters and sea lochs on the west coast of Scotland. Following their immigration into inshore waters in the Bristol Channel and Inner Severn Estuary, young whiting became infected with the copepod parasites Lernaeocera branchialis and Clavella adunca and the metacercariae of the heterophyid digenean Cryptocotyle lingua. Prevalence of infection was less in 0+ than older fish and infection by L. branchialis caused a significant decline in condition. As whiting became larger, the main site of attachment of Clavella adunca changed gradually from the wall of the branchial chamber to the primary rakers of the first gill arch. Vertebral counts suggest that the whiting which enter the Inner Bristol Channel and Severn Estuary are not representatives of the populations found in the Irish Sea.

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