METEOROLOGY — THEORY 203 
laboratory. During these flights meteorological sound- 
ings were made as frequently as possible. The labora- 
tory was fortunate in obtaining from the Washington 
State College group one of their original sonde units 
and has adapted this equipment for use in the air- 
plane soundings. The temperature and humidity ele- 
ments were mounted in an unobstructed aluminum 
housing approximately 14% ft above the nose of the 
PBY-5A airplane. 
Since the airplane served the dual purpose of ob- 
taining both meteorological and field strength meas- 
urements, all tlie data were obtained on a fixed course. 
Field strength sections were made in rapid descents 
and the meteorological data were obtained in ascents. 
Navigational difficulties prohibited spiraling for the 
meteorological data and theréfore these soundings 
covered considerable horizontal distance. Due con- 
sideration of this. was made in plotting the cross 
sections. 
The San Diego High Inversion 
In the summer season San Diego lies within the 
belt of the subtropical anticyclones, and, with the 
absence of surface frontal activity, a stagnant circula- 
TEMPERATURE te DEGREES C 
900% 
Tae 
920 
MILLIBARS 
sai 
DATE — SEPTEMBER 29, 1944 
TIME — 1512-1517 PWT 
LOCATION- 300 TRUE 45 MILES 
10/10 STRATUS 
1000 
FAA 
Cane ai 
Ha 
SVCVLAN 
AN 
Ficure 5. Structure of a moderately high inversion near San Diego. 
