Geoscience Reference
In-Depth Information
used there. The aerosols microphysical parameters were specified and the total
set of the desired optical parameters (in our case the aerosol absorption and
scattering volume coefficients and the phase function of the aerosol scattering
at the fixed altitude and spectral grids) were calculated with them. As the prob-
lem of the modeling was obtaining the a priori statistical parameters of the
aerosols, they were calculated by the variations of the microphysical parame-
ters. This methodology of modeling and the aerosol model itself are presented
in detail in the study by Vasilyev and Ivlev (2000).
The considered inverse problem of the retrieval of atmospheric optical pa-
rameters from the data of solar irradiance observations has no analogs in
contemporary literature. Thus, we aim the study at the principal possibil-
ity of the retrieval of atmospheric parameters from the data of the irradiance
measurements and also to the revealing of themethodological algorithmshort-
comings. Therefore, we are presenting the analysis of
all
retrieved parameters
of the atmosphere including even the parameters whose obtaining from the
observational data is of no practical interest (the profiles of temperature and
humidity). Moreover, we are presenting some erroneous results, which are of
interest from the point of elucidating methodological shortcomings of the al-
gorithms. The results of the retrieval of the aerosol parameters are certainly the
most important ones, especially from the aspect of constructing and improv-
ing the aerosol models of the atmosphere. However, it should be emphasized
that, if the number of the accomplished experiments with the processed results
islessthantenforeverytypeofsurface,itwouldnotbeenoughforstatis-
tical analysis of the results and for presenting them as models. Nevertheless,
it is possible to limit our consideration with the most typical results because
they are the robust (statistically stable) estimation of the mean values of the
aerosol parameters for constructing the aerosol models. The obtained results
are presented in Tables A.8-A.11 of Appendix A.
Figure 5.4 illustrates the examples of retrieving the temperature vertical
profile. The specific features of the profiles, particularly, the strong maximum
at the level 500mbar, hardly correspond to the real altitudinal temperature
behavior in the atmosphere, so they have been caused by the essential system-
atic uncertainty during the retrieval of the temperature profile. It is easy to
explain with the significant temperature dependence of the irradiance within
molecular absorption bands. In particular, it concerns oxygen narrow band
760 nm. However, as has been mentioned in Chap. 3, while describing the ob-
servations with the K-3 spectrometer the large systematic uncertainty could
appear within the oxygen band connected with the shift of the wavelength
scale owing to the mechanical scanning of the K-3 instrument. Besides, the
instrumental function obtained from the measurements in the VD spectral
region can (moreover, from the properties of spectral instruments, it has to)
show the relationship between its halfwidth and spectral region and can be
wider in the NIR region. Note that both specific features are clearly seen in
comparison of the observations and calculations, illustrated by Fig. 5.3. As the
oxygen content is fixed, while solving the inverse problem, the temperature
profile is the only parameter, which links with the absorption band shape and,
which could be varied in the algorithm. The systematic uncertainties of the
Search WWH ::
Custom Search