Remote-Sensing Technologies and Data Processing Algorithms - New Ecoinformatics Tools in Environmental Science: Applications and Decision-making - page 142

surface is considered the emission and re fl ection coef cients are correlated by the

ʺ 0 | 2 . Consequently the knowledge of emission coef formula κ =| cient allows to

estimate the re cient and electrophysical properties of ground. Under

this it is necessary to know the soil temperature T or to calibrate the radiometer
using the land covers with emission coef

fl ection coef

cients which are known. Theoretical bases
of remote methods, as a rule, have approximate character. This has to do with the
need for simpli cations often used

are uniformity of environmental parameters distribution by the depths or height,
absolute transparency of the area, the land covers smoothness. The models syn-
thesized under these simpli

ed prepositions. For example, among the simpli

ect restricted spectrum of the studied phe-
nomenon properties. That is why the estimation of model adequation is necessary.
The problem of wavelengths choice and the combination of its ranges with the
classes of solved tasks is now within sight of many investigators. Theoretical
foundation of this choice lies in the area of the thermal radiation transmission
theory. Speci

cations re fl

cally, for the monochromatic case the transmission equation has

dI ðÞ= dz ¼ J ðÞa I ðÞ; ð 2 : 3 Þ

where cient, J(z) is the emission source distributed by z,

I(z) is the emission intensity in the point z. Under this for the unscattering atmo-
sphere the following equation is valid: J(z)=

ʱ is the absorption coef

ʵ 1 (z)B(z), where ʵ is the atmosphere

emissivity,

h i 1

exp f hf kTð ðÞ

1

B ðÞ ¼2hf 3 c 2 g ;

c is the frequency. For the microwave
branch where the observed frequency is in the region of a few hundred gigahertz or
less it takes place a condition hf

h, c and k are fundamental constants, f = ʽ

≪ kT and the Rayleigh-Jeans approximation is

ʻ − 2 . Here k = 1.38 10 − 20 mW Hz − 1 K − 1 valid: B(z)=2kT × is the Boltzmann ' s

constant, is the wavelength.

The Eq. ( 2.3 ) has solution

ʻ

Z 1

T j ¼ j T e sð 0

;1Þ þ

T ð u Þ Q ð u Þ du

; ð 2 :

4 Þ

0

where

2
4

3
5 :

Z

b

sð a ; b Þ ¼exp að z Þ dz

a