G N ðv i ; h j Þ ¼ 2:55 Á 10
À3 v
2
i Dv H2O ðh j Þr H2O ðh j Þ
Tðh j Þ
Â
Ã3
2
:
(3.23)
Where n H2O ¼ 22:235 GHz; r H2O h j
À Á
[g/m
3
] is the water vapor density at the
altitude h j ; the dimensions of the value G R and G N is [1/km].
Calculating the halfwidth of absorption H 2 O line at the frequency n ¼ 22.235
GHz is done according to the following:
D n H2O h j
À Á ¼ 0: 126
p h j
À Á
T h j
À Á
Â
Ã
0:626
1 þ 0:011
r H2O h j
À Á
T h j
À Á
p h j
À Á
"
#
:
(3.24)
If there is no observational information then simulating the vertical profile of
absolute humidity looks as:
r H2O h j
À Á ¼ 7:5 exp À
h j
1:74
:
(3.25)
If the specific humidity profile q (g/g) is known the value r H2O (g/m
3
) is calculated according to:
r H 2 O h j
À Á ¼
288:87p h j
À Á
q h j
À Á
T h j
À Á
0:62197 þ 0:37803q h j
À Á
Â
à :
(3.26)
3.4 Practice 2
3.4.1 Objectives
1. To study the approach for direct calculation of the absorption coefficient of
atmospheric gaseous components on the base of using data of the fine structure
parameters and getting skills of forming data and accomplishing computer
calculations.
2. To study the fine structure parameters dependence on the atmospheric pressure
and temperature within the spectral IR interval.
3. To study the approach for calculating characteristics of the atmosphere absorption in case studies of values of the absorption coefficient within oxygen
absorption at the wavelength l ¼ 2.53 mm.
4. To study the following characteristics in IR and Microwave intervals basing on
the analysis of the results of calculating the atmosphere absorption coefficient:
– the absorption coefficient dependence on the wavelength;
– the absorption coefficient dependence on meteorological parameters.
3.4 Practice 2
35