USE OF THE INFRARED THERMOMETER IN ROUTINE COASTAL SURVEY — A SUMMARY 



by John R. Clark and Richard B. Stone, Sandy Hook Marine Laboratory, 

 Highlands, New Jersey 



INTRODUCTION 



The Sandy Hook Marine Laboratory has used the Barnes infrared thermometer (IRT) 

 in coastal sea surface temperature surveys since the summer of 1962. In December 1962 a 

 series of monthly surveys of the surface waters of the Continental Shelf off New York and New 

 Jersey was initiated. The program was expanded in January 1964 to include the area from 

 the eastern tip of Long Island to Nantucket Shoals. Our IRT sea temperature survey is de- 

 signed to provide near-simultaneous observations of temperature and water movements over 

 an area of 16,000 square miles. (See Figure 1) This program has provided a special kind of 

 experience of value to the Workshop because of its regular repetitive nature. The program 

 has been briefly mentioned and the features of the instrument discussed previously by Clark 

 and Frank (1963). 



Aircraft for the survey are furnished by the U. S. Coast Guard Air Stations, Brooklyn, 

 N. Y. and Salem, Mass. The standard Coast Guard search and rescue craft, the Grumman 

 UF2G ("Albatross") has proved ideal for this work. The survey is made in flights of about 

 five hours each, on consecutive days if possible, to provide near-synoptic coverage along the 

 1800 miles of flight track. 



The IRT is utilized to record a single parameter of the environment, surface tempera- 

 ture, over large areas in a short time. The data are utilized in ecological studies; specifically, 

 to help explain the influence of temperature on the distribution of migratory fishes and upon 

 seasonal cycles of ocean productivity. However, the IRT measures only the "micro-surface" 

 (the upper 0.1 mm) and can be considered only an indicator of the near-surface layer tem- 

 perature. The program requires that near-surface temperature be estimated to ±2.0°F.; 

 this is possible if the micro-surface temperature can be measured to ±1.0°F. 



Conventional shipboard temperature measurements, by bucket and immersion therm- 

 ometer, normally refer to the upper meter but also provide a biological useful index of tem- 

 perature for the whole mixed layer in the relatively shallow waters of the Continental Shelf. 

 Our goal could be defined most simply as an attempt to estimate "bucket -depth temperature" 

 with a maximum error of ±2°F, It now appears that under some circumstances this goal can 

 be reached easily but under others only with some difficulty. 



The greatest problem has been correcting for the difference between temperatures of 

 the micro-surface and temperatures of the immediate subsurface, the conventional "surface 

 temperature" or bucket temperature. We could find no data in the literature which could be 

 used to estimate bucket temperatures from micro-surface temperatures under varying en- 

 vironment conditions. Until such data are obtained it will be difficult to estimate bucket 

 temperatures to closer than ±3°F. 



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