Analysis of Radiative Observations in Cloudy Atmosphere - Short-Wave Solar Radiation in the Earth's Atmosphere - page 249

sublayers within the uncertainty range. The scattering coefficient is maximal
for the inner sublayers close to the cloud top. The obtained vertical profile of
thevolumescatteringcoefficientissimilartotheairborneresultsaccomplished
in stratus-cumulus cloudiness in the Southern hemisphere (Boers et al. 1996)
and to the results of the FIRE experiment in the Arctic (Curry et al. 2000). The
same values are cited in the topic by Mazin and Khrgian (1989) for stratus
clouds. Thus, our results could be assumed to be the quite real ones.
Figure 7.10 illustrates that most pixels are characterized with optical thick-
ness τ 0 about 10-25, while in some regions consisting of several pixels the

optical thickness reaches 70-80 and even 100 (in the Tropical latitudes). Space
variations of the optical thickness seem rather monotonic in images obtained
from the satellite data, and this obstacle points to the low enough uncertainty
of either observations or data processing.
The presented results of the retrieval of optical thickness τ 0 and single scat-

ω 0 fromthe airborne, ground, and satellite radiative observations
demonstrate the similar values and spectral features in spite of using different
observational methods and different formulas. It shows the inverse asymptotic
formulas to be quite suitable for obtaining the cloud optical parameters. The
elaborated method has more advantages comparing with the other methods
(Rosenberg et al. 1974; Asano 1994; Nakajima TY and Nakajima T 1995; Rublev
et al. 1997) because it provides obtaining two parameters for every wavelength
in the shortwave spectral range and for every pixel of the satellite images
independently and with no additional restricting assumptions.
The approximate account of the cloud top inhomogeneity turns out to be
rather effective either for inverse or for direct problems. The introduced shadow
parameterturnsouttotakeintoaccounttheupperatmosphericlayersinfluence
together with the uncertainty of the phase function approximation with the
Henyey-Greenstein function. It will be promising to analyze the results of
similar data processing in the global scale.
It should be mentioned that the more accurate presentation of the phase
function would change the numerical magnitudes of the results because it has
to retrieve the phase function parameter for substituting its real value instead
of the model one to the formulas.

tering albedo

7.5
Influence of Multiple Light Scattering in Clouds on Radiation Absorption

7.5.1
Empirical Formulas for the Estimation
of the Volume Scattering and Absorption

The results discussed in the previous section have common features, namely:
1. magnitudes of the single scattering albedo are lower than the values
calculated with Mie theory,
2. and the existence of the spectral dependence of the optical thickness
contradicted Mie theory results.