Low Thin Stratus 



Upon passing over low scattered thin stratus (tops less than 100') prior to going over 

 solid overcast, no effect on temperature was noted until the aircraft passed over the solid 

 overcast. At this point the IRT readout usually dropped at least 2-4° F. The possibility 

 exists that the temperature of the low thin stratus is very close to sea surface temperature, 

 and this may account for no observable temperature change. 



Rain Showers 



Variable effects on sea surface temperatures have been found when entering rain- 

 storms. A noticeable drop in temperature has sometimes been experienced when entering 

 winter rainstorms. This drop appears to be more common in the northern latitudes, as it 

 has been encountered in flights off the central and northern portion of the West Coast. This 

 reduction in temperature could be the effect of low temperature rain or hail in the field of 

 view or a cooling of the water surface upon which it fell. Light summer rain showers do not 

 usually appear to affect sea surface temperature readout, probably because the rain is near 

 water surface temperature. 



Air Temperature 



Experience with the airborne radiometer off the West Coast has been confined to the 

 temperate zone from latitude 32° N. to 48° N., an area not noted for large differences be- 

 tween air and sea temperatures within the lower portion of the marine layer. Air tempera- 

 tures were obtained at the 500' M.S.L. level on three survey flights (see figures 2-4). Tem- 

 peratures were obtained by positioning a thermistor probe in the aircraft slipstream. The 

 probe readout temperatures were corrected for dynamic heating as a function of air speed 

 and rounded off to the nearest °F.,usingthe formula: T = (A.S.) ^ A.S. (air speed) in mph., T 



100 

 in "C. At an estimated air speed of 130 loiots T = 2.25° C. or approximately 4° F. higher 

 than true ambient air temperature. 



Weather conditions during the flights (figures 2-4) were: 



Figure 2. — Southern half, overcast 1000" to 1500' broken to scattered, 

 ♦ wind 0-8 k, W-SW, visibility 10 miles. Northern half, 



broken to scattered, wind 0-10 k. W-N^\^ visibility reduced 

 to 3 miles in Santa Barbara channel area. 



Figure 3. — Overcast, solid to scattered, wind 10-15 k. I>rW^ Offshore 

 from Pt. Conception area, 0-6 k. elsewhere. 



Fig-ure 4. — Overcast, solid, wind 0-5 k. SW. 



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