Results of research on surface waves of the western North Atlantic. I. Investigation of bottom pressure fluctuations and surface waves. II. Results of sea surface roughness determinations in the vicinity of Woods Hole, Mass., and Bermuda
Seiwell, Harry Richard
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Part I: It is to be expected that in the future, measurements of pressure fluctuations beneath the ocean surface will provide basic data for solution of many practical problems on the state of the sea. As a result of the wartime impetus, several types of underwater pressure recorders (of similar instrumentation principles) were developed both in this country and abroad. Essentially, the instrument consists of an underwater unit which electrically transmits pressure impulses near the sea bottom to a clockwork recorder installed on the shore. The underwater pressure unit is adjusted for pressure fluctuations resulting from surface waves within the spectrum band of periods set up by winds acting on the sea surface. The resulting records may be scaled for height and period of the pressure fluctuations over known time intervals. An accessory wave analyzer has been constructed for rapid periodogram analysis of the pressure records. This investigation is concerned with a comparative study of observed sea surface waves and recorded sea bottom pressure fluctuations. It was undertaken for the purpose of evaluating sea surface wave heights from sea bottom pressure recordings in the vicnity of Woods Hole and Bermuda. Part II: The results presented here comprise data on the state of the sea surface in the vicinity of Woods Hole (off Cuttyhunk Island, Massachusetts) July 1946 to May 1947, and off Bermuda, British West Indies, February 1947 to May 1947, obtained from analyses of automatic wave recordings. At both locations measuring elements of the wave recording instruments were located on the sea bottom (approximate depth 75 feet at Cuttyhunk and 120 feet at Bermuda) and electrically connected to shore recorders several miles away. The instrument operational schedules were continuous twenty minute recordings every two hours at Bermuda and every six hours at Cuttyhunk.