= 654 - 
Bandwith, respectively, was 25 nm. 
Ref lection standard was not used. 
Incident hemispherical irradiation measurements were 
made, instead, with the same telespectroradiometer. 
3. DATA PROCESSING 
3.1 Preprocessing 
The irradiance and reflected radiances recorded by the measurement 
system were digitized and stored on magnetic tape. They were 
then corrected using the calibrated spectral response of the op- 
tical sub-system of the measurement system. For visual checking, 
the corrected curves were plotted in a drum plotter. A number 
of curves were omitted at this stage from further analysis be- 
cause of the measurement problems referred to above. The spectral 
reflectance factors were then calculated as follows (c.f. Kriebel, 
1977): 
(6) RO) = ce, - AO Arr 
where 
L, (8 ) = reflected radiance averaged over the 
horizontal projection of the solid an- 
glen (f= 1 steradian) 
E, = irradiance 
C, = correction factor for the acrylic 
plate used as a diffuser in irradiance 
measurements 
No other corrections were made. 
3.2 Analysis 
For statistical analysis, the R(A)-curves were sliced into 20 
and 40 nm wavelength bands for which the R(A)-values were calcu- 
lated and stored in a disk file. In the analysis, the R(\)-val- 
ues of different sample plots on the same channel were compared 
and the impact of various stand characteristics on the R(A)-