The Problem of Retrieving Atmospheric Parameters from Radiative Observations - Short-Wave Solar Radiation in the Earth's Atmosphere - page 132

The Problem
of Retrieving Atmospheric Parameters
from Radiative Observations
This chapter presents a general statement of the problem of determination of
atmospheric and surface parameters from observational results of radiative
characteristics. The methods of determining the parameters of the radiative
transfer theoretical model providing the minimal standard deviation (SD)
between the numerical and measured results for the correspondent charac-
teristics are considered below in detail. The choice of a concrete set of the
parameters, the influence of systematic uncertainties of the numerical simu-
lations and the technical realization of the considered methods are discussed
further.
4.1
Direct and Inverse Problems of Atmospheric Optics
Hereinbefore described in Chaps. 1 and 2 we have demonstrated the possibil-
ities for solving the problem of calculating the solar radiance and irradiance
after setting the parameters of the atmosphere and ground surface (volume
coefficients of absorption and scattering, phase function, and surface albedo).
Furthermore, the results of the characteristic radiative observations have been
presented in Chap. 3. Therefore, this gives us the possibility of relating the
problem of selecting the atmospheric parameters, which allowed computing
values to be equal to the measured characteristics. The problems considered in
Chap.2,i.e.calculationsoftheobservationalcharacteristicswiththechosen
parameters of the atmosphere and surface, are specified as direct problems
of atmospheric optics . Contrary to this, the problems considered below, i. e.
determination of the atmospheric and surface parameters from observational
results of the radiative characteristics, are specified as inverse problems of
atmospheric optics .
The solution of the direct problem implies the creation of the mathemat-
ical model of observations , on the basis of which one can relate the physical
notions concerning the interaction of radiation with atmosphere and surface
(see Chap. 1). We should point out two important obstacles for further consid-
eration.
Firstly, the choice of the physical and consequently mathematical models
of the mentioned processes is ambiguous. Actually, while creating the mathe-
matical descriptions, different idealizations of the concrete physical processes