A sample calculation using this formula reported by the Naval Oceanographic Office 

 showed an error of l.G°F. as the maximum to be found at 1,600 feet. It was brought out 

 that the heterogeneity of the air mass involving temperature and humidity can affect the re- 

 sult of such calculations. It was noted that the amount of water vapor in the air is inversely 

 related to the distance from the surface of the water. It is recommended to stay below the 

 inversion layer when using the IRT. Since error caused by water vapor is a function of the 

 altitude it was pointed out that the closer the plane can fly to the water the better, from an 

 accuracy standpoint. Below 200 feet the problem may in fact be very small. For mstance, 

 at 300 feet altitude a typical error correction might be 0.3° F. When there is precipitated or 

 dispersed liquid water, IRT readings should not be attempted since no reasonable correction 

 formula can be supplied. 



It was brought out by the technical representative that we should be able to correct 

 the IRT readings to one significant figure if we have information on water vapor, air tem- 

 perature, absorption, reradiation and sky reflection. 



It was suggested that a family of curves be made up for ready correction of the re- 

 cords under various conditions of humidity, temperature, etc., to give rough conversion 

 factors. If a higher degree of accuracy is required, calculations could be made directly 

 from the formula. 



Reference to water vapor formula: Meteorological Satellite Laboratory, Report 10, 

 U S. Dept. of Commerce, Weather Bureau, August, 1962. Infrared Flux in Temperature 

 Determination from Tiros Radiometer Measurement, E. U. Wark, T. Yamato, J. Lienesch. 



Wind The major effect of wind on IRT surface temperature records is to increase 

 evaporaU^T^nd reduce the difference between the temperature of the microsurface and that 

 of the immediate subsurface. Wind increases evaporation and sensible heat transfer and 

 reduces the microsurface gradient. In extreme heating or cooling situations wind can 

 sometimes have a pronounced effect (up to 2°C. or more). The effect will depend upon the 

 gradient which otherwise would build up in the absence of the wind. In any event it is not 

 possible now to handle this mathematically. Wind is one of the parameters m an analysis 

 now being undertaken at Texas A. & M. on data obtained during the cooperative cruise 

 aboard the OB . On infrared seamier records, whitecaps typically show up as cold patches. 



Question 5. What factors other than meteor o logical act at the air-sea interface to 

 affect the accuracy of the IRT sea- surfa ce temperature determination? 



The only factor of possible significance in this comiection is contamination, such as 

 "oil slicks", which can affect results when using instruments of ^^^^^^^f ^^fo^"^" '° 'j^'^.^d 

 but have little effect, if any, on survey work where limits of accuracy of O.o C. are imposed. 



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