A thermistor chain was attached to FLIP with 30 thermistors located at 

 10-foot intervals between depths of 10 and 300 feet (3.3 and 91m). The 

 thermistors were scanned at 6-minute intervals for periods of 18 hours a 

 day, and at 50-second intervals for two 3-hour periods a day and for two 

 27-hour periods. Unfortunately, several breaks occurred in both the 6-min- 

 ute and 50-second series. 



From the R.V. HORIZON, 23 hydrographic casts were made--one each day 

 except on September 5th and 10th when seas were too rough. The first two 

 and the last casts were made to 1,200 meters; the others, to 600 meters. 

 Salinity determinations were made aboard the R.V. HORIZON by use of the con- 

 ductive-type salinometer developed at the University of Washington. Oxygen 

 determinations were made by the Winkler method. Just prior to each cast, a 

 bathythermograph (BT) temperature observation was taken so that the Nansen 

 bottles might be arranged to sample more closely the layers where and when 

 temperature inversions were present. A total of 1,004 BT observations were 

 taken. These included an almost continuous hourly series from September 4th 

 to 26th, and two 24-hour series taken at 10-minute intervals. 



Only those aspects of the oceanographic program related to the variabil- 

 ity of the temperature-depth structure and, indirectly, to the sound veloc- 

 ity-depth structure will be discussed here They will include: (l) varia- 

 bility of the temperature-depth structure related to internal waves and to 

 season; (2) results of the time-series analysis of the 6-minute thermistor- 

 chain temperature record, including power spectra, auto-correlation func- 

 tions, and time lag statistics of the oscillations of selected isotherms; 

 (3) T-S curves and envelope of observed T and S values showing changes in 

 T-S depth structure which produce a secondary sound channel at approximately 

 100 meters depth; and (4) implications of these observations for prediction 

 of oceanographic parameters and for Navy operational and observational 

 programs . 



DISCUSSION 



The time variation in the temperature-depth (T-D) structure is illus- 

 trated by the selection of BT traces shown in Figure 3 1. The three single 

 traces in the top row indicate the three principal variants in the T-D 

 structure encountered at FLIP'S location: (l) no separation between sea- 

 sonal and permanent thermoclines ; (2) seasonal and permanent thermoclines 

 separated by a 50-meter layer of almost isothermal water; and (3) a tempera-. 

 ture inversion at the bottom of the seasonal thermocline . 



In the last figure on the top row, traces 1 and 3 have been superimposed, 

 indicating differences observed in a 4-hour period. The additional figures 

 indicate, in time intervals of 20 minutes to 26 days, differences in depth 



1 



Figures 3, 4 and 5 have been included in the text to take the place of the 

 time-lapse movie of the hourly and 10-minute BT series presented at the 

 Symposium . 



408 



