81
measured radiances about the sun. If the angular asymmetry exceeds 10%, those pairs are removed from the
inversion process. If the integrated asymmetry exceeds 10% or there are not a sufficient number of data
points, the data are not inverted. The inversion routine used is that of Nakajima, (1983) and has a number
of options that will be implemented over time.
The principle plane data are processed using the same inversion however only data on the zenith
side from the solar disc are used in the inversion due to asymmetry induced by the ground reflectance. The
principle plane window has identical capabilities as the almucantar window. The test for the quality of the
data is simply the smoothness of the curve.
wave < m) t(<sun>>
Almucantar
II 1619
X
n 070
X 670
■ “ i
A 440
device
3
wave<u> t(<sun>) t(sun> t<sky>
err
1019 0
3185 0
.3195 0.2594
0.0087
070 0
4242 0
.4238 0.3530
0.0080
870 0
6913 0
.7064 0.6015
0.0494
440 1
4473 1
.4913 1.3666
0.1100
waves
wexp<sun>
wexp<sky>
440/070
1.8001
1.9856
440/670
1.7572
1.9516
670/070
1.8692
2.0403
440/1019
1.8025
1.9787
870/1019
1.8128
1.9489
Figure 3, A successful inversion of almucantar radiances during clear (3a) and hazy
(3b) conditions is possible when the data are symmetric about the sun (upper
left plot within window). Inversions produce a volume size distribution with
good accuracy from 0.1 pm to about 3 pm aerosol radii. The aerosol optical
thickness and phase function (right side of window) from the aureole inversion
are also computed using Nakajima's (1983) code.