Introduction 



Ocean station ECHO is located in the North 

 Atlantic Ocean at latitude 35° 00' N. and longi- 

 tude 48°00' W. Previous to September 1966, 

 this station was monitored by the USCGC 

 CASCO (WHEC 370) during the period 29 

 January-16 February 1963 in a joint effort 

 with the U.S. Naval Oceanographic Office. The 

 results of that study are presented in the U.S. 

 Coast Guard Oceanographic report no. CG- 

 373-2. 



Procedures 



During the period September 1966-October 

 1967, U.S. Coast Guard cutters conducted hy- 

 drographic casts on five patrols at ocean station 

 ECHO. Nansen casts were made daily at 14 

 prescribed levels to 1500 meters, weather and 

 operating conditions permitting, during the 

 three-week patrols. The cutters were also in- 

 structed to make a deep cast to near bottom at 

 least once during the patrol. On shallow casts 

 the prescribed sample depths were as follows: 

 0, 25, 50, 75, 100, 150, 200, 400, 500, 600, 800, 

 1000, 1250, and 1500 meters. The prescribed 

 depths for the deep casts were 2000, 2500, 3000, 

 and 150 and 50 meters off the bottom. 



Two deep-sea reversing thermometers were 

 attached to each Nansen bottle. Between the 

 depths of 200 and 1500 meters one unprotected 

 thermometer was used on 5 Nansen bottles to 

 determine thermometric depths. Depths which 

 were determined thermometrically are preceded 

 by a "T" in the station data. Tables I-V. Field 

 observations were returned to the U.S. Coast 

 Guard Oceanographic Unit (CG Oceanographic 

 Unit) for reduction to "in situ" temperature 

 and determination of sample depths. The pro- 

 cedures used in recording and processing of 

 thermometer data are similar to those in 

 U.S.N. HO Pub. No. 607 (1955) and LaFond 

 (1951). The CG Oceanographic Unit used a 

 Digital Equipment Corporation PDP-5 com- 

 puter to determine corrected temperatures for 

 the protected thermometers, and thermometric 

 depths of the unprotected thermometers. 



Water samples were drawn from each Nan- 

 sen bottle and stored in sample bottles for 

 salinity determinations. The salinity was deter- 

 mined aboard ship using induction salinom- 

 eters. Duplicate samples were drawn from the 

 top and bottom bottle of each cast and delivered 

 to CG Oceanographic Unit for quality control 

 purposes when the vessel returned to port. 



All oceanographic data collected by the ocean 

 station vessels were transmitted via radiotele- 

 type to CG Oceanographic Unit for real-time 

 processing and quality control. The tempera- 

 ture data were then passed on to the Fleet 

 Numerical Weather Facility, Monterey, Cali- 

 fornia. 



Processed temperature and salinity data were 

 recorded on form NHO/NODC-3167/1 (1-61), 

 "Physical and Chemical Data Form for Ocean- 

 ographic Stations" and delivered to the Na- 

 tional Oceanographic Data Center (NODC). 

 The interpolated temperatures and salinities for 

 standard depths, sigma-t, specific volume 

 anomalies, and sound velocities were computed 

 by NODC and are presented in Tables I-V. 



The ocean station vessels are normally re- 

 quired to maintain stations within a ten-mile 

 square grid. The actual positions of the stations 

 taken on each patrol are shown in figures 3-7. 

 Thirteen of the 89 stations were taken outside 

 of the ten-mile grid. 



The USCGC YAKUTAT (WHEC 380) oc- 

 cupied 23 oceanographic stations during the 

 period 21 September-13 October 1966. During 

 this highly successful monitoring of ocean sta- 

 tion ECHO, 22 stations were occupied. Samples 

 ranged in depth from 1399 to 1536 meters. One 

 deep cast was made to 4106 meters in a water 

 depth of 4224 meters. The distribution of these 

 stations about ECHO is shown in Figure 3. The 

 data are listed by NODC as Ref. No. 31-767 YA 

 and as Table I of this report. 



During the period 4-25 February 1967, 18 

 oceanographic stations were occupied by the 

 USCGC MCCULLOCH (WHEC 386). Of the 

 18 stations taken, 17 were shallow casts ranging 



