Preliminary Report EAC #32 2 - 11 December 1967 EGS #18 3 - 10 December 1967 Support Ship: USS Tioga County (LST 1158) Cruise Itinerary: 2 December (0800) - depart San Diego 3 December (1135) - Enter Grid at Pt. Ash 10 December (0910) - depart Grid at Pt. Ash 11 December (0900) - Arrive San Diego. Personnel: R. L. DeLong (BIC) T.J. Lewis R.L. Brownell Methods: Diurnal observations were held from the bow, the forward gun mounts, and the lee wings of the bridge as weather conditions dictated. No nocturnal observations were conducted. The skiff was used for 2 hours on 7 December; one storm petrel was collected. No bathythermograph casts were made due to lack of equipment. Cruise track & conditions: The cruise track (Figure 1) was altered from the normal on two occasions due to heavy weather. The LST class ship is not a satisfactory observation platform in the survey area. The ship rolls severely while running in the trough; and pounds unceasingly while running into the sea. During this survey with prevailing seas from the west severe pounding was encountered on all westerly legs. As the ship pounded on a swell and entered a trough it "shuddered" with 60-90 vibrations per minute. The constant abnormal ship movement did not allow observers to use glasses for scanning, thus the numbers of birds observed were certainly fewer than normal. This bias may approach a 25 percent reduction in observability from the normal conditions. Weather during the survey was affected by a number of various sized, fast moving fronts. Moderate to heavy seas prevailed through all but two days of of the survey. Sea temperatures (recorded as sea water injection tempera- tures in the engine room) varied only two degrees in the survey area. These readings (if accurate) indicate a very flat temperature field throughout the Grid, resulting from seasonal cooling at the surface and consequent over- turning and mixing in the upper layers. The coding and mixing may have been accelerated this month because of the several cold fronts passing through the area. The N.E. Pacific has been averaging 3-5° F. warmer than normal during this past summer and early fall. Rapid cooling would tend to bring tempera- tures back toward seasonal normal.