64 



here are to obtain a rather high speed of thermal response and to keep the 

 measuring element very small. The measuring elemients would probably be 

 used in gangs horizontally or vertically. It would seem that a speed of response 

 of l/lO second and a temperature sensitivity of .01°C are required. The 16 

 channel thermistor-recorder designed by NEL is fairly close to this but the time 

 constants are too long to study very small scale turbulence. 



b. An Instrument For Studying Micro Structure And The Isothermal 

 Layer: This instrument should have similar characteristics to the above instru- 

 ment except that it only needs one element and needs to go to depths of several 

 hundred feet. 



c. A Reliable BT To 1500 Meters To Study and Survey The Main Ther- 

 mocline: This instrument should be continuously recording with a temperature 

 precision of at least .03°C. It probably must be self-contained although an 

 ability to record on deck via acoustic data transmiission would be highly desir- 

 able. A resistance thermometer might well be the most satisfactory measuring 

 element. 



d. A Sensitive Recording BT To Study Temperature Structure Below The 

 Thermoclin^T In order to determine the characteristic and origin of deep water, 

 it is desirable to be able to find any discontinuities in the deep temperature 

 structure. 



e. Infra Red Instrument to Study Heat Flow Across The Surface: The 

 possibility of using an infra red sensitive device to look for horizontal tempera- 

 ture gradients on the surface of the water is very interesting. Used either by 

 aircraft, or from a ship's mast, such an instrument may be extremely useful 

 to delineate current and eddy boundaries in a way which would be impossible by 

 conventional means. In view of the large temperature differences found in the 

 ocean, it would appear that many very interesting problems could be attacked 

 with fairly simple equipment. 



Devik has published some work on surface temperatures in Norwegian 

 lakes measured by infra red pickups in recent years. While the state of the 

 art of such devices is rather limited, it would seem that standard bolometer 

 techniques would permit seeing temperature differentials of a degree or two. 



f. A Long Period Temperature Recorder: Oceanography has not had 

 the chance to stuay temperature records extending over a long period of time 

 and hence we are uncertain about how rapidly major thermal changes take 

 place. In particular we do not know how important large transients, such as 

 eddies, influence the temperature. Klebba of Woods Hole has designed a re- 

 cording thermonneter which can record for a year but it has yet to be used over 

 any extensive period at a critical location. In coastal areas it will probably be 

 wiser to have the recorder operate over a shorter time. The sensitivities of 

 such recorders should probably be from 0. 1 to 0.01°C and the thermal stability 

 must of course be excellent. 



g. A Bottom Temperature Recorder: A bottom temperature recorder 

 such as the one designed by BuUard and by Scripps should be made available so 

 that problems in heat-flow out of the bottom can be studied. 



h. Cheap BT For Harbor And Limnological Work: A cheap BT for har- 

 bor and limnological work should be made. Tnis does not have to be used un- 

 derway and the depth ranges need only be 100 feet. Here I would recomnnend a 

 bellows type pressure element working against an extension spring. The ther- 

 mometer should probably be bimetalic as it is cheap and almost foolproof and 



