The modelling of energy-mass exchange, it will be recalled, is
conventionally subdivided into several stages. The first stage is to
provide a schematic map of the area under investigation, to
determine the configuration and boundary conditions for models
of the natural environment. The second stage is to draw up a
computation pattern and to establish direct and reverse energy-
mass exchange problems. The third stage is to interpret the
results obtained as a basis for decision-making.
The complexity of each stage is due, as a rule, to a shortage of
data, which are traditionally obtained by point observations (bore
holes, wells, individual sampling points on the Earth's surface,
etc.). During the modelling process it is essential to employ
generalized integrals to describe the characteristics of specific
components of the model. For this
purpose, we need a sufficient volume of data for each component
in the model. This is not realistic using the existing traditional
method. Regularisation methods used in reverse modelling
operations help to solve problem only in part, usually leaving a
considerable measure of uncertainty in the parameters used, and
consequently also in the calculated forecasts. Practice shows that
the uneven distribution of point data in spatial and temporal
terms is a particular problem, so that researchers are often
compelled models which subjectively interpolate or extrapolate
the data available.
The use of remote sensing data makes hydrogeological modelling
more efficient. At the stage where natural conditions are mapped,
data are used from aerial and satellite images in the microwave
. and IR bands, which allows alimentation and discharge zones of
underground waters to be identified and contoured, the ground
flow height (H) to be identified for areas where the groundwater
level is not deep, the infiltration input (W) level to be evaluated
for specific homogeneous areas, usually on the basis of
formalized resolutions for any point on the surface of the Earth.
The experiments performed show that multispectral aerial and
satellite images allow us to identify homogeneous landscape
zones and the level of underground waters and also to pinpoint
areas with an elevated contaminant (C) concentration of soils and
vegetation (for example, with radionuclides). By combining
structural deciphering of various remote sensing materials with
data obtained from ground-based geophysical sampling, lines are
revealed which are associated with the distribution of tectonic
zones. These in turn determine zones with an elevated filtration
porosity of
rocks, especially in the vertical direction.
This method currently being used in full for the area affected by
the Chernobyl disaster.
3. CONCLUSIONS
A methodology and a set of programs have been developed for
ecological monitoring using multispectral satellite images:
- approaches have been developed which allow comparable
results to be obtained from images produced by different
equipment at different times and in different weather conditions;
- an analysis of change in the radioecological situation in the
Chernobyl NPP zone from 1984 to 1995 showed;
- the station had noticeable impact on the ecological situation in
the area even before the accident;
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998
- radionuclides originating from human activity had the greatest
impact on pine forests, a lesser influence on deciduous forests
and a still lesser impact on grasslands;
- the impact of the accident's consequences on pine forests is
still manifest today; over a period of 10 years from the time of the
accident the environment has been gradually cleansed of
radionuclide contamination, but the background radiation level
has increased noticeably at the same time;
- even low concentrations of less than 10 Ci/km Cs-137 in the
soil have a noticeable influence on the spectral reflectance
brightness of vegetation and can be seen on multispectral satellite
images .
The use of remote sensing materials allows expenditure on
radioecological studies to be cut by dozens of times since the
volume of ground-based work is reduced, this work can be better
targeted and large areas can be covered whenever the need arises.
A reliable model of energy mass exchange in geosystems must
incorporate data obtained by remote sensing of the Earth. This
permits a more dependable evaluation of hydrogeological
peculiarities and a forecast of the development of the ecological
situation as a basis for well-founded administrative decisions.
The methods developed for processing multispectral satellite
images can be applied to an objective evaluation of the impact of
the Chernobyl disaster on the ecological situation at any point in
time, both in Ukraine and other European countries, to establish
the impact on the atmosphere of NPPs, places of storage of
radioactive waste, thermal power stations and other man-made
constructions.
LITERATURE
Chernobyl disaster . Kiev, Naukova dumka, 1995, 560 p.
Collins W., Chang S.B. Raines G. et. al. Airborne biogeophisical
mapping of Biddan Minaral Deposits // Econ. Geol. - 1983, n 18,
(4) p. 734 -749. Horler B. et. al. The red edge of plant leaf
reflectance. Int. J. Remote Sens. 1983, 4 - p, 273 - 283.
Demetriades-Shah T.E., Steven A.D., Clark J.A. High Resolution
Derivative spectra in Remote Sensing. Remote Sens. Environ.
1990, n 33 (1) p. 55 - 64.
Baret F., Jacquemoud S., Guyot G and Leprieur C. Modeled
Analysis of the Biophisical Nature of Spectral Shifts and
Comparison with Information Content of Broad Bands. Rem.
Sens. of Environment, 1992, v. 41,
N 213, p.133-142.
Lyalko V.L et al. Aerospace methods in geoecology. Kiev,
Naukova dumka 1992. 206 p. (in Russian)
Sportjuk Z.M., Lyalko V.L, Pyanilo Ya.D., Sibirtseva O.N.,
Pyanilo T.M. Spectral methods of processing and analysis of
information in Remote Sensing of vegetation . Lviv, 1993, 53 p.
(in Ukrainian).
Lyalko V.L, Djary V. Yu, Sakhatsky A.L, Hodorovsky A. J.,
Woolfson L.D. Shportjuk Z.M., Sibirtseva O.N. Marek
K.-H., Oppitz S., Gimel’farb G.L, Ilieva V. “Estimation of
Heavy Metal and Radionuclide Contamination of the
Soils and vegetation within the Chernobyl Danger Zone
Using Remote sensing Data”. Proceedings. of the XYIII th
Congress of the International Society for Photogrametry and
Remote Sensing, Vienna, Austria, vol. XXXI, part B7,
Commission YII. pp. 454 - 459. 1996.
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