observation of sea slicks from shore sites (Dietz and LaFond, 1950; 



Ewing, 1950). The degree to which investigations of near shore and 



deepwater internal wave phenomena are similar must await further 

 scientific study. 



II. RESEARCH OBJECTIVES AND PROCEDURE 



Aside from operational development of fixed platform environmental 

 research, an initial step in this study was to determine the existence 

 of internal temperature variations and subsequently to gain sufficient 

 knowledge to design an observation system. Minimal single- station 

 measurement at a single level in July 1959 provided the basis for 

 layout of the three-station system described in the following section. 

 This was specifically arranged for detecting the passage of "discrete" 

 internal temperature variations (or signatures) which retained sufficient 

 identity of form to be recognizable at all three stations. Through 

 observation over extended periods, continuity or regularity of 

 occurrence could be established and a comparison could be drawn 

 between fall and spring features of the internal phenomena. From the 

 analysis of data collected during a multiple ship survey made in 

 conjunction with observations at Texas Tower No. 4 during April 

 I960, it is intended in a future report to estimate the degree of horizontal 

 uniformity within a distance of 1 5 miles from the tower. 



III. FIELD MEASUREMENTS 



Field data considered in this report were collected during the fall 

 of 1959 and the spring of I960 in the vicinity of Texas Tower No. 4. 

 The tower (hereafter designated TT4) was located about 70 miles 

 southeast of New York Harbor on the north shoulder of the Hudson 

 Canyon in a water depth of 185 feet (Figure 1). 



The sensing system consisted of a taut-wire submerged buoy with 

 platinum resistance thermometers affixed at pre-selected levels (Figure 

 2). A spherical, 14-inch-diameter, Japanese, glass fishing float provided 

 vertical lift. The net woven around the float was attached to a 3/32-inch 

 steel cable which in turn was linked to a 100- to 150-pound gravity 

 anchor. The 3/8-inch electrical lead cable from each resistance 

 thermometer was taped or tied to the 3/32-inch cable and spliced near 

 the anchor to a common cable laid on the ocean bottom to the tower. 



