AIRBORNE RADIATION THERMOMETER ON THE PACIFIC COAST OF CANADA 



by J. P. TuUy, Pacific Oceanographic Group, Fisheries Research Board of Canada, Nanaimo, 

 British Columbia, Canada 



An oceanographic information service was initiated on a trial basis in 1959. As else- 

 where, this depended on reports of sea surface temperature from transmitting ships and 

 bathjthermograms from Naval and research vessels. The data income was not adequate 

 for any useful interpretation. Two approaches were taken to solve this dilemma (1). 



By concentrated research in existing data (2), particularly from Ocean Station "P" 

 (Lat 50°N, Long 145°W), models of the daily behaviour and seasonal growth and decay of 

 the thermocline in the eastern subarctic Pacific were developed. These models revealed 

 that during the heating season, the depth to the top of the seasonal thermocline was a 

 function of wind history. During the cooling season it was a function of convection. During 

 the heating season transient thermoclines occurred in the potentially isothermal layer above 

 the seasonal thermocline. Their occurrence would be revealed by the signature of any 

 continuous temperature recording device. Also such a device would reveal the occurrence 

 of "fronts" where the thermocline turned up towards the surface (divergence areas) or 

 where surface waters accumulated (convergence areas). 



Some acquaintance with an Airborne Radiation Thermometer was acquired by 

 borrowing Richardson's prototype equipment from Woods Hole Oceanographic Institution (3). 

 It fulfilled all expectations. There were not adequate resources to provide a routine daily 

 air patrol over the area for thermometry purposes alone. However, there were and are 

 military air patrols covering the United States and Canadian areas. These could carry 

 equipment if it was small enough, light enough, would work unattended and provided infor- 

 mation of military significance. This required redesign of Richardson's equipment. No 

 commercial manufacturer was interested in such a venture, therefore the Pacific Oceano- 

 graphic Group developed a prototype (FRB-1) (4) which was flown during the heating season 

 of 1961. On the basis of this experience (5, 6) construction of a more erudite model (FRB- 

 2) was undertaken and is in the final stages of completion. 



The equipment consists of a scanning head, a computer-recorder unit (Information 

 Channel) and a Tactical Channel which has a visual indicator. These units are small and 

 can be separated by 50 feet distance in the aircraft. The total weight is about 50 pounds. 

 The equipment is turned on at the beginning of a flight. The information channel records 

 apparent temperature on a suitable scale (there are nine scale brackets). The tactical 

 display shows a green light when the rate of change of temperature is less than one Celsius 

 degree per 10 miles, yellow when it is one degree per 5 to 10 miles, and red if the change 

 is more rapid. This system indicates sudden changes (fronts) and erratic signature 

 (transients). 



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