Geoscience Reference
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microwave-range. However, disturbed surface areas covered with thin oil
films are
characterized by lowered values of T
Y
, due to the suppression of high-frequency
components in the rough sea spectrum. The value and sign of the radiation contrast of
the spills on the clean water background depend on the thickness and optical prop-
erties of the oil
films, the hydrometeorogical conditions, the time of the day, etc.
Fundamental experimental investigations of water oil pollution by means of
microwave- and IR-radiometers have been described by many authors (Mitnik
1977; Bogorodsky et al. 1976). Field experiments have shown that satisfactory
results were attained when radiometers with wavelengths of 8
m, and 0.34,
0.8, 1.5 and 8.5 cm were used. The sensitivity of the radiometer relative to its
antenna inputs equaled 0.1
12
ʼ
-
0.3 K under the time constant of 1 s. The experiments
-
were performed with a
flying laboratory at a height from 100 to 200 m. The
radiometers were calibrated using blackbody radiobrightness temperatures or by
means of calculations for a calm water surface under a cloudy sky. Thin
fl
films are
recognized with high accuracy by means of IR-radiometers. Most thick
films are
detected with high reliability by means of microwave radiometers.
The oil
film thickness can be estimated by the dependence of the radiobrightness
temperature variation
ʔ
T
Y
, on the emittance ability,
Dj
:
;
D
T
Y
¼
Dj
T
0
1
T
Y
;
atm
=
T
0
where T
0
is the surface temperature, T
Y,atm
is the atmosphere radiobrightness
temperature calculated by radiosensing data and the value (1
−
T
Y,atm
/T
0
) charac-
terizes the in
uence of the atmosphere.
The geometric parameters of the oil films are defined by means of photogram-
metric methods the base of which is the spectrozonal photo-picture on the various
wavelengths. The ranges 0.4
fl
m are the most informative for
solving this task. The oil products registered with wavelengths 0.4
0.5 and 0.7
0.8
ʼ
-
-
m are a
light spot upon the dark background of the water image. The image registered by
wavelengths 0.7
0.5
ʼ
-
m helps to decipher the water surface.
The registration of the oil spills can be realized by means of active sensing
methods. For example, the oil spill exposed by the near ultraviolet radiation begins
fl
0.8
ʼ
-
fluorescence in the visible range (0.6
0.7
ʼ
m). This
fl
fluorescence can be registered
-
by the adaptive identi
er in the real time regime (Krapivin et al. 2001).
The above methods allow us to consider two versions of the monitoring system
for controlling the gas extraction zone. The
first version corresponds to the oil
extraction system situated completely below the water surface where the stationary
position of remote sensing systems is impossible. In this case, the monitoring
system structure has submerged measuring subsystems
xed by anchors and
emerged subsystems placed on
floating laboratories. The estimation of the
concentration of pollutants emitted to the atmosphere is realized by modeling
calculations. For this aim, the gradient of the gas components and the advection
speed are measured in the surface layer. Moreover, it is possible to use the emerged
measuring sub-systems.
fl
flying or
fl
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