immersion thermometer readings taken by surface craft. Checks were also made with sur- 

 face readings taken from towers and piers. From this it is concluded that when proper 

 operating procedures are followed, the IRT can estimate surface water temperatures with- 

 in ± 1.0°F. The effect of water vapor in the air path was shown to amount to somewhat less 

 than -0.5° F. at 500 feet altitude, with visibility near the surface of about 6 miles (in 

 November). In preparing isotherm charts for the surveys the instrument is read every 

 30 seconds in flight and an average is drawn for every two minutes; these are the data 

 points for the isotherm drawings. 



In discussion it was explained that it was their procedure to take one observation 

 each 30 seconds and to average it by two-minute periods in order to smooth out any small 

 fluctuations in the data. It was pointed out that problems of interpreting records and draw- 

 ing isotherms are unique to each area. The need for standardization in interpretive techni- 

 ques was brought forth, as was the need to accumulate the data in such a way that it can be 

 handled by computers. Mr. Squire mentioned that after plotting the smoothed curves they 

 did then go back and inspect the record and show the fronts separately if they were con- 

 cealed by smoothing. The consensus appeared to be that continuous inspection of the strip 

 chart record for plotting isotherms was better than averaging or taking selected points 

 along the line. It was pointed out that this is a simpler technique to manage in practice 

 where there are good temperature gradients. The continuous inspection technique was 

 explained to mean that the strip chart record was inspected for increases or decreases 

 past the plotting interval, whether 1 or 2 degrees, and these being only the data point re- 

 corded along the flight track. A problem arises, however, with storage and retrieval of 

 these data, about which some general accepted standard should be found. 



John W. Reintjes : Comments Relative to Infrared Workshop 



The Bureau of Commercial Fisheries Biological Laboratory in Beaufort, N.C., has 

 participated in the cooperative program of the SEAS Committee. The method of operation 

 is similar to that used by Sandy Hook Marine Laboratory and the Virginia Institute of 

 Marine Science which, together with the Beaufort effort, extend the monthly synoptic 

 coverage from Cape Fear, N.C., to Cape Cod, Mass. The usual operating problems, as 

 expressed by others who spoke earlier, were encountered in the work. The differences 

 between lightship observations and aircraft IRT readings were as high as 3°F. but tests 

 made in December and April with plane and research vessel gave differences between IRT 

 and bucket-depth temperatures of small fractions of a degree F. The limits of accuracy 

 of the technique appear to be ± 0.5°F. which easily meet the minimum for areas of sharp 

 gradient such as are encountered between Cape Hatteras and Cape Fear, N.C. 



Floyd C. Elder (Extemporaneous Remarks) 



The University of Michigan Department of Meteorology and Oceanography has seven 

 IRT instruments in use on various vessels in the Indian Ocean Expedition. The Department 

 also has carried out some work with the Barnes IT-2 on two research ships in the Great 

 Lakes area for studies of energy exchange at the air- sea boundary layer. In the near future 

 there will be some testing operations comparing research tower IRT readings with floating 



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