Geoscience Reference
In-Depth Information
them from consideration as remote-sensing tools. Clouds have a powerful effect on
light radiation and create obstacles to land surface observation from space over
many territories (Klyuev 2000; Justice et al. 1995; Grankov 1994; Asrar and Dozier
1994).
Knowledge of the atmosphere admitting function in the given synoptical and
geographical conditions is the key task under the synthesis of the remote monitoring
system. As a rule this task is solved during the realization of measurements. For
this, one or several channels use waves that are relatively powerfully absorbed or
are dispersed by different atmosphere components; these are added to the basic
channels. The content of relative component is determined by the effect of these
waves relaxation on the various latitudes (or the integrated content, depending on
the task). The measurement results correction is introduced by the basic channels
using these additional data.
The speci
ed physical special features of the environment remote sensing are
inherent to the super high frequence and ultra short waves ranges which are the
foundation of the radiometric geoinformation monitoring systems. These systems
allowed the many tasks involved in operative identi
cation of natural phenomena to
be solved and new methods and technologies for remote diagnosis of natural and
natural/technogenic systems to be developed.
Microwave methods can be conditionally divided into two classes: active and
passive. The methods that study the character of the reflection, scattering and
absorption of the waves emitted by the source with known spectral density are
de
ned as active. The optical range includes such sources: the Sun, lasers and other
light emitters. Active methods used widely in radiolocation systems are in the radio
range. The power of re
ected and dispersed radiation, its spectral composition and
polarization characteristics, phase and propagation time are the study objects in this
case.
Passive methods are based on the heat emission analysis of natural formations.
The fact that thermal emission is determined by substance temperature and its
physical parameters is taken into account here. That is why passive methods are
used for the temperature measurement and for the determination of different
environmental parameters. These measurements are effective particularly under
multi-channel sensing co-ordinated with the data processing algorithms (Sarkisyan
2000; Sellers et al. 1996; Krapivin and Mkrtchyan 1991; Bondur et al. 2010;
Krapivin et al. 2010a, b).
Let us now move on and consider the speci
fl
c features of radiophysical methods
(i.e., those in which the radio waves are used). Basic attention is here concentrated
on the SHF-range since namely this range is applied in the remote sensing systems
located on
fly-laboratories and satellites (Kondratyev 2000a; Kondratyev et al.
1990a; Krapivin and Phillips 2001; Shutko et al. 2010). Microwave radiometer
systems are used intensively on numerous satellites. These systems secure the
operative control of more then twenty basic geophysical parameters forming
weather and climatic processes (Bondur et al. 2009).
Main speci
fl
c features of radiometric methods are connected with high radio-
clearness of the atmosphere. It is one of its advantage in comparison with optical
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