Preliminary report on long-period variations in the transport of the Gulf Stream system

Abstract

In 1937 the Woods Hole Oceanographic Institution and the Bermuda Biological Station for Research agreed to cooperate on a five year program of observations. This was designed to throw light on the general problem of long-period fluctuations in the transport of the Gulf Stream, and their possible significance for fisheries research and for meteorology. The investigation originated at the suggestion of the Bermuda Oceanographic Committee of the Royal Society of London, which also arranged for a generous grant of money to enable the Bermuda laboratory to undertake part of the field work. A summary of the ideas on which the original program was based has already been published (Iselin, 1938a) and more recently two short papers (Iselin, 1938b, 1939) have emphasized certain aspects of the theoretical considerations on which it rests. Although the primary objective has been a study of long-period trends in the strength of the Gulf Stream and only two and a half years have elapsed since the work at sea began, nevertheless it now seems desirable to set forth some of the preliminary results and to discuss further the underlying assumptions. It is hoped that in this way we can gain the benefits of criticism and thus be more wisely guided during the remainder of the five years for which continued field work is now planned. In preparing this report I have had the assistance and advice of the staff of the Woods Hole Oceanographic Institution. I am especially indebted to Dr. Sidney C. T. Hsiao who prepared the final drawing of the diagrams and carried through the necessary computations. In addition, I have worked in close cooperation with Dr. E. F. Thompson of the Bermuda Bio.logical Station and Mr. H. B. Hachey of the Atlantic Biological Station. It is most gratifying to have taken part in an investigation with so many willing and helpful participants.