Several experiments have been carried out in order to determine speed and direction of surface drift in relation to the wind speed and direction. Some of the best observations of drift of oil patches was obtained after the Torrey Canyon accident in 1967. A special study of these observations in open sea are described. The geostrophic wind speed and direction at sea level corresponding to the drift observations has been computed from carefully analysed sea level pressure maps. The 'geostrophic wind factor' (drift speed/geostrophic wind speed) computed by least squares method gave as result the value 1.8 percent. Assuming that the actual wind speed in the mean is 2/3 of the geostrophic wind speed (due to friction), the actual wind factor amounts to 2.7 percent. The direction of drift appears to be close to the direction of the geostrophic wind in the mean for all cases. This indicates a drift angle to the right of the actual wind direction approximately equal to the mean deviation of the actual wind direction from the geostrophic. 15 degrees to the right of the wind seems a reasonable value. This value is well confirmed by separate studies of groups of the data corresponding to winds in the southwest sector (stable air, large frictional effect) and in the northwest sector (unstable air, small frictional effect). The drift vector is composed by two components, one which is a direct effect of the drag of the wind upon the oil surface (directed along the wind direction), and secondly one which is due to the surface current generated by the wind. Assuming a 45 degrees deviation of the surface current, one arrives at a wind factor for the direct effect of the wind upon the oil of 2 percent.

  • Supplemental Notes:
    • Abstract of paper delivered at the First International Conference on "Port and Ocean Engineering under Arctic Conditions" held at Trondheim, Norway, August 23-30, 1971
  • Corporate Authors:

    POAC Conference

  • Authors:
    • Haug, O
  • Publication Date: 1971

Subject/Index Terms

Filing Info

  • Accession Number: 00025705
  • Record Type: Publication
  • Source Agency: Arctic Institute of North America
  • Files: TRIS
  • Created Date: Mar 28 1973 12:00AM