Undulations in Lakes and Inland Seas Due to Wind and Atmospheric Pressure

Abstract

IT is generally known that considerable variation takes place in the level of the surface of the water in lakes and inland seas owing to the effect of the wind in gales and during stormy weather. The minor undulations which occur at more regular intervals have not attracted the same observation, and the cause of these is still a matter of some uncertainty. In the large lakes in America, fishermen and boatmen have learnt to regard these undulations as storm warnings; and on the coasts of Europe, the rollers which break on the shore in calm weather are looked upon as indicative of a coming storm. Thus, in the Bay of Biscay frequently during the autumn and winter in calm weather a heavy sea gets up and rolls in on to the coast four-and-twenty hours before the gale which causes it arrives, and of which it is the prelude. In this case the wave action, generated on the other side of the Atlantic by the wind, travels at much greater rate than that of wind, and thus gives timely warning of the coming storm. So also on the opposite side of the Atlantic, on the coast between North Carolina and Cape Hatteras, the currents, which are there largely governed by the wind, begin to run strongly several hours in advance of the wind which causes them. In summer a change of the current from north-east to south-west is always taken as a true indication of an approaching north-east wind.