METEOROLOGY — FORECASTING 255 
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ORY BULB TEMPERATURE 
PSYCHROMETRIC NOMOGRAM FOR COMPUTING M 
MIT RADIATION LABORATORY 
300 1000. 1100. 1200 1300 1400 1500 
| | | q i n sh 
300 350 400 450 
HEIGHT IN METERS 
700 800 
200 250 
TOF 7 GOFF RS SOF 895% OF Se 
WET BULB TEMPERATURE 
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Ficure 23. Psychrometric nomogram. 
soundings immediately after the squalls showed the 
usual duct. (Sea surface temperatures were constant 
at 84 to 85 F. Close to the surface the temperature 
lapse rate was superadiabatic, but it was dry adia- 
batic above 100 ft.) 
OBSERVATIONS UPON Ducts OTHER THAN 
SIMPLE SurFrAcE TRAPPING 
Although the emphasis in this report is placed upon 
simple surface trapping, nonstandard propagation is 
found under other distributions of atmospheric mois- 
ture and temperature. Elevated inversions are found 
up to around 5,000 ft, due to subsidence in anti- 
cyclones over the Pacific’; the western and the 
southern portions of this area usually exhibit the 
higher elevations. Illustrative of one of the other fac- 
tors in nonstandard propagation is the Fohn wind 
