EFFECTS OF METEOROLOGICAL CONDITIONS 



Haze Effect 



On November 21, 1962, observations were made of surface water temperatures off a 

 pier in north San Francisco Bay with a Barnes 14-312 mounted in a Cessna 172C and com- 

 pared with simultaneous mercury temperatures taken from the pier. Five observations were 

 made at 500' M.S.L., six at 1000', three at 1500', two at 2000' and two at 3000'. The weather 

 was clear, wind calm, visibility 6 miles, haze level extending to an estimated 2100' M.S.L, 

 Variations at each elevation, compared to a simultaneous reading of water surface temper- 

 ature were: -0.2° to -0.5° F.@ 500', -0.2 to -0.5° F. @1000', -0.5°@ 1500', -0.7° to -0.8°F. 

 @ 2000' and -0.7° to -1.0° F.@3000'. Observations were averaged for each elevation, 

 giving a reduction in temperature from bay water temperature of -0.32° F.@ 500', -0.36°F,@ 

 1000', -0.50° F. @ 1500',-0.72°F.@ 2000' and -0.85° F. @ 3000' (see figure 1). The greatest 

 change in readout temperature was within the first 500' (-0.32° F.), indicating that haze plus 

 the possibility of evaporative cooling as described by Ewing and McAlister (1960) might be 

 affecting the readout. A stratification of haze was not apparent to the eye within the layer 

 although the haze appeared to be denser in the lower 1000 feet. On figure 1 a straight line, 

 fitted by eye, from the 500' to the 2000' observation level in weather condition as indicated 

 above indicates an approximate reduction of -0.68° F. per 1000 feet. 



-3.000 



Condlltoni: 



Cltor.Vtl 6 mtlti .hot* loytf 

 to 2,000'm • I 



-0.1 -02 -03 -0.4 -0.5 -0.6 -0.7 -0.8 -0.9 

 DEGREES CF) 



Figure 1. Haze effect observations; November 21, 1962; 

 1348-1447 P.S.T.; North San Francisco Bay 



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