relations between the spectral characteristics are 
different to those with the same vegetation before the 
accident. The character of this relation is more similar to 
that for vegetation growing on heavily contaminated 
areas. This confirms the method proposed to allow the 
detection of quite low contamination of vegetation by 
radionuclides. The existence of low level radioactive 
contaminations influence on vegetation is shown by 
radiobiologists (Chernobyl disaster), too. 
A three-dimensional plot for description of the relation 
between the spectral characteristics of pine forest in red 
and near-infrared bands and Cs-137 contamination in 
coniferous canopy was set up to prove the possibilities of 
using multispectral space photographs for the 
assessment of Cs-137 content in vegetation. According 
to this plot the dependence is unimodal. Vegetation with 
high Cs-137 content in needles and branches has high 
brightness values in the two bands, too. This behaviour 
was expected due to a direct dependence between the 
content of Cs-137 and other toxicants in soil and in 
vegetation which was observed in ground observations. 
In order to predict radioactive soil contamination 
regression equations were derived. Three-dimensional 
plots have shown the dependence between the spectral 
characteristics of the major biocenouses in the test site in 
the red and near-infrared band on the one hand, and the 
soil content of Cs-137 on the other hand. All the plots 
show a quite simple unimodal relation between the 
According to 
values. these plots 
analyzed 
one can conclude that, the higher the contamination of 
soils by radionuclides, the higher the spectral brightness 
of plants in each band. According to the results of several 
authors, as expected for pine forest, this relation i; 
manifested most clearly that, associated with the Strong 
sensibility of pine forest, as a critical ecosystem for 
radioactive impact (Figure 1). 
   
RA 
Ci / km? 
432: AS 
ICA MEE 
A EZB TUS A ioqvietiasiB9 
1583 ne i 
NIR 9269 RED 
(relative value) (relative value) 
Fig. 1: Relationship between the content of radionuclides 
RA (Ci / km?, Cs-137) and spectral brightness in 
red (RED) and near infrared (NIR) band of a 
space photograph (multispectral camera MK-4 on 
satellite ,Ressource-F", July 27, 1989, 13.57) for 
pine forests on dry soils, Chernobyl test site 
  
  
  
  
  
  
  
  
  
Soil contamination by Cs-137 ( Ci / km?) 
  
[3o:s 3 > 7 
[^5 dio 20 
[1-10 E3530 
  
linn 
>35 
NPP Chernobyl Nuclear Power Plant 
Borderline of the 30 km zone 
Fig. 2: Prediction scheme of soil contamination by 
CS-137 derived from red and near infrared 
band of a space photograph 
(multispectral camera MK-4 on satellite 
,Ressource-F“, July 27, 1989, 13.57) 
Chernobyl test site 
  
458 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996 
— RN —" P) sc ed 
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