water depth of 4,755 meters. Wind and sea condi- 

 tions prohibited oceanographic operations a total 

 of 10 days during the patrol. The distribution of 

 the stations about the center of DELTA is shown 

 in figure 6. The data are listed by NODC as Ref. 

 No. 31-850 DU and as table V of this report. 



The USCGC CASCO successfully occupied 23 

 oceanographic stations during the 20 March-11 

 April 1967 patrol on DELTA. One cast had a 

 maximum sample depth of only 666 meters due to 

 the cast snagging some unknown object and the 

 subsequent loss of four Nansen bottles with their 

 thermometers and 1,175 meters of cable. Another 

 cast had a maximum useful depth of 780 meters due 

 to malfunctioning of thermometers in the deeper 

 bottles. The remaining 21 casts had maximum 

 sample depths between 1,300 and 1,700 meters. 

 One deep cast was accomplished with a maximum 

 sample depth of 4,410 meters in a water depth of 

 4,663 meters. The distribution of the stations about 

 the center of DELTA is shown in figure 7. The 

 data are listed by NODC as Ref. No. 31-888 CS 

 and as table VI of this report. 



During the 11 July to 3 August 1967 patrol of 

 the USCGC SPENCER on DELTA, 18 oceano- 

 graphic stations were successfully taken. Two 

 casts had maximum useful depths of less than 

 1,300 meters due to wire angles in excess of 40°. 

 The remainder of the casts had maximum sample 

 depths ranging from 1,400 to 1,700 meters. One 

 deep cast was accomplished with a maximum 

 sample depth of 3,585 meters in a water depth of 

 4,537 meters. The distribution of the stations about 

 the center of DELTA is shown in figure 9. The data 

 are listed by NODC as Ref. No. 31-1091 SC and 

 as table VIII of this report. 



DISCUSSION 



As a result of the station dispersion on the cruises 

 of the USCGC ESCANABA and USCGC 

 CAMPBELL (see figs. 2 and 3), cross sections of 

 temperature and salinity were constructed along 

 the lines A-B and C-D to illustrate the presence of 

 the diffci'ent water masses in the vicinity of Ocean 

 Station DELTA. These lines were selected to in- 

 clude the maximum number of stations and still 

 preserve a certain amount of synopticity in the 

 data. Figure 10, the temperature and salinity cross 

 sections along line A-B in July 1966, reveals a 

 tongue of relatively cold (9-13° C), low salinity 

 (35.1-35.4%o) water between 50 and 300 metere 

 from the north and a tongue of warm (13-16° C.), 

 high salinity (35.8-36.1%o) water from the south. 



Between these two water masses is a frontal zone 

 which probably contains an easterly flowing cur- 

 rent due to the general sloping of the isolines down 

 to the east. 



Figure 11 shows the cross sections of tempera- 

 ture and salinity along line C-D in Augusts- 

 September 1966. These data were taken in approxi- 

 mately the same location as those in figure 10, but 

 the large gradients, both vertically and horizon- 

 tally, observed in July are not evident. The tem- 

 poral variations are therefore also significant, at 

 least on a monthly scale. 



Analysis of the data from the eight patrols on 

 Ocean Station DELTA revealed that significant 

 variations did occur in the data both in time and 

 space during the particular 21-day periods on sta- 

 tion. The data from each patrol are therefore pre- 

 sented as deviations from a mean value at each ob- 

 served level. Obviously anomalous stations which 

 were occupied out of the Ocean Station grid were 

 not included in the averaging. Figures 12 through 

 19 contain the mean temperature versus depth and 

 mean salinity versus depth curves for each patrol. 

 Accompanying these curves are tables 1-8 in which 

 are tabulated the maximum, minimum, and mean 

 values of temperature and salinty at each stand- 

 ard level. Also tabulated are the standard devia- 

 tions (lo-) of the values from the mean. 



Vertical temperature distribution : 



The mean curves from the eight patrols reveal 

 a basic stratification of the water mass at Ocean 

 Station DELTA: (1) A surface layer responsive 

 to the seasonal variations in incident radiation, 

 (2) a body of water with a temperature of 12-14° 

 C. between 200 and 400 meters, (3) a permanent 

 thermocline (6-12° C.) and (4) North Atlantic 

 Deep Water below 1,000 meters. The thermal 

 structure from July 1966 to January 1967 changed 

 from the situation of a large negative gradient in 

 the upper 50 meters (21° C. to 17° C.) to a nearly 

 isothermal structure in the upper 150 meters with 

 a temperature in the range of 14.00-14.70° C. 

 From January 1967 to July 1967 a seasonal 

 tliermocline was again established in the upper 50 

 meters. (See figs. 20 and 21) 



There were rather anomalous conditions ob- 

 served in the October-November patrol of the 

 USCGC HUMBOLDT. The water was signifi- 

 cantly warmer between 100 meters and 800 meters 

 than at any other time of the year. The water was 

 from 0.5 to 1.0° C. warmer than the summer ob- 

 servations. This may have been the result of the 



