way used to determine the vertical thermal 

 gradient to 400 m. to facilitate selection of sam- 

 pling depths for the subsequent Nansen cast. As 

 a result vertical thermal gradient sampling rather 

 than standard depth sampling was accomplished. 



A small shipboard fabricated marker buoy of 

 light construction, floated by 12 inner tubes 

 riding to 570 fathoms of nylon and dacron line 

 secured to a 10-foot length of chain and a 75- 

 pound danforth anchor was used in conjunction 

 with the Hytech ELBT for a preliminary and 

 cursory internal wave study. This buoy was lost 

 due to a loss of floatation. 



For iceberg drift studies a Geodyne Corp. 

 toroidal fiberglass buoy equipped with a tripod 

 mast, antenna array, and Motorola Co. radar 

 transponder, Model SST-133X, was moored with 

 a fixed bridle, swivel, ballast ball, 120 fathoms 

 of 1 inch braided nylon, one shot (15 fathoms) of 

 one-half inch anchor chain and a 75-pound dan- 

 forth anchor in a reference position. Evergreen's. 

 radar was used hourly to determine navigational 

 positions and the drift track of the berg with refer- 

 ence to the buoy. Horizontal control is estimated 

 to be valid within 200 to 300 yards. The buoy 

 was an unqualified success, operating at radar 

 ranges of up to 12 miles and up to 70 hours on a 

 single charge of the two serial 12 volt standard 

 truck type, lead acid cells. 



Twin drogues made of 28-foot cargo parachutes 

 suspended at 10 and 70 meters depth from a buoy 

 of truck type inner tubes and bamboo poles, and 

 equipped with a radar reflector and light were used 

 as an adjunct to the iceberg drift study for acquir- 

 ing subsurface current information. 



Personnel 



The oceanographic work of the first and second 

 cruises was under the direction of Lt. Comdr. 

 Richard M. Morse, USCG who was assisted by 

 Lt. Comdr. Ronald C. Kollmeyer, USCG; Mr. 

 Thomas C. Wolford, oceanographer, USCG; Mr. 

 Robert B. Elder, oceanographer, USCG; and 

 Ens. Melvin S. Swanson, USCGR. Lieutenant 

 Commander Kollmeyer directed the third cruise 

 assisted by Mr. Wolford and Ensign Swanson. 

 Technical assistants for the entire season were 

 David C. Lockhart, aerographer's mate first class 

 and Edward S. Olszewski, sonarman second class. 

 Dennis L. Noble, aerographer's mate first class; 

 John T. Nichols, sonarman second class; and 

 James D. Brower, aerographer's mate third class 

 assisted during the first and second cruises; and 



William H. Harrell, sonarman first class; William 

 E. Heller, aerographer's mate second class; and 

 David J. Wood, sonarman second class assisted 

 during the third cruise. 



DYNAMIC HEIGHT CHARTS 



General 



The dynamic height topographic charts of the 

 sea surface, for the Grand Banks region of 

 Newfoundland, are presented in figures 2A 

 through 5A. They were constructed from data 

 obtained on the first, check, second, and third 

 surveys conducted during Ice Patrol 1965. 



The first and third survey charts, figures 2A 

 and 5A, represent data obtained using the new 

 station array. They describe the surface currents, 

 their velocities and directions, as determined from 

 dynamic computations. The check survey, figure 

 3A, consisting of section U and a portion of the 

 the section immediately to the south was obtained 

 appro.ximately 1 week after the occupation of 

 these same stations on the first survey. The 

 purpose of this immediate reoccupation was to 

 examine short term changes that may occur in the 

 flow pattern of the Labrador Current not de- 

 tected in the past due to intervals of a month or 

 more between surveys. 



The second survey chart, figure 4A, is a sup- 

 plemental survey of the northern area, adjacent 

 to the main region of interest. It provided the 

 characteristic description of the easterly flow and 

 southward turning of the Labrador Current prior 

 to its entering the area of major interest. 



The third survey, figure 5A, describes the 

 circulation in the area of major interest during 

 the late spring. Flow patterns are quite different 

 than found in early spring as seen in figure 2A. 



The designated section U is noted on figures 

 2A, 3A, and 5A. This section includes the most 

 interesting flow patterns of the region. Starting 

 at the westernmost end of the section, the typical 

 high stand of Banks water is always observed 

 which grades into the main southward flowing 

 stream of the Labrador Current. Just to the 

 east of this current, a trough or low stand of 

 mixed water is found with the northward flowing 

 Atlantic Current fonning the eastern boundary of 

 the section. The circulation changes which oc- 

 curred in this section between the several surveys 

 will be discussed in detail in the following sections. 



