= 1296. - 
+ cavity temperature: 45 + D.59C 
+ Coverage: at 1000ft altitude a 32 ft 
diameter circle, 
at 1200ft altitude a 36,40ft 
diameter circle 
The installation on board of the aircraft was made as 
shown in figure 2. 
Data Reduction 
A) Calibration of the instrument 
The calibration of the radiometer may be well accomplished 
by comparing the kinetic temperature of two water containers at 
different temperatures and taking this calibration ag reference 
for the measurements. This procedure is very simple but it does 
not account for some factors that may influence the recorded 
temperature, playing a non-neglectable role when thermal sea 
surface temperature from lou altitude is measured. Hence that 
it was felt that a careful correction should be attempted. 
The voltage output of the PRT-5 is related to the measured 
temperature and in a first order approximation it may be stated 
that: 
- \ 2 fo ‘ 
Tg 5 aV. b (8C) (1) 
where: Ta = Barnes measured tenperature 
a, b are constants depending on the selected range 
is the outpu 
sal Jt voitage of the PRT-5 in the high 
"" level mode (0«V S5) 
sal 
Measuring for tuo different temperatures: 
T Ww , 
Tg 5 8.4 y+ (2a) 
TÉ x a WEL + (2b) 
8 sal 
Solving simultaneously the system of linear equations 2a, 2b 
, 
one obtains: