< 



Figure 9. Wind direction and surface isotherm pattern, southern 

 California, May 2, 1963 



Initial IRT survey temperatures (Aug.. Sept., Oct. 1963) for all three West Coast areas 

 were higher than sea surface temperatures observed by conventional methods (Anon., 1963). 

 Temperature error was greater in the northern surveys where air temperatures @ 500' 

 were lower. In checking on this it was found that in the laboratory the normal heater cycle 

 sequence in the IRT detector was 7 seconds on and 22 seconds off. This cycle time while air- 

 borne was extended to a sequence of up to 60 seconds on and 7 seconds off. The Barnes Engin- 

 eering manual for model 14-312 infers that if the instrument was cycling at all, it could be 

 considered to be operatii^ properly. 



To test the instrument while in flight, the detector head housing was removed from the 

 Jato rack and the water surface observed by looking through the lower half of the port hatch. 

 With the detector inside the aircraft, recycle time became normal (laboratory sequence), and 

 the IRT readout dropped about 7° F. to 62.9° F., -0.4° F. lower than surface temperature ob- 

 served by the N.E.L. oceanographic tower. Erratic fluctuations in chart record were greatly 

 reduced and did not exceed 1° F. 



The IT -2 instrument lacks a heater cycle on-off indicator due to the addition of a solid 

 state proportional temperature controller. Therefore, an accurate check of heater operation 

 is not possible. Tests indicate the chart record developed by the IT-2 increases in fluctuation, 

 after a period of time when the detector head is exposed to a light slipstream. Retraction of 

 the detector head two or three inches has eliminated excessive chart fluctuations. 



-88- 



