Environmental Engineering Reference
In-Depth Information
Figure 4. Trondheim Fjord. City of Trondheim (circle) and the station Trollet (triangle).
Diffuse attenuation coefficients were retrieved at four wavelengths in the UV
range at different depths. The parameter S was calculated according to equation 5 for O
between 305 and 380 nm. In this fjord S varied between 0.012 to 0.015 in the surface
layer (between 0 and 1.0 m) during the year (Figure 5). At one occasion S became much
smaller (0.007), which indicated a larger k d at 380 nm compared with 305 nm. This
event was in the spring (Figure 5). K d s were in general very low after a long winter.
When the spring bloom started and more phytoplankton was present absorbing in the
blue, the spectral shape of the absorption changes caused a different S. K d s at 305 nm
varied between 1.8 and 9.1 measured in the surface layer. At 380 nm the lowest were
0.9 and the highest 3.1.
1503
904
2905
2606
1309
1511
1312
29.05: S=0.013
26.06 S=0.014
13.09: S=0.015
09.04: S=0.012
13.12: S=0.013
15.03 S=0.007
15.11: S=0.013
Figure 5. Diffuse attenuation coefficients retrieved during 1999 (15-03, 09-04, 29-05, 26-06, 13-09,
15-11, 13-12) at 305 nm, 320 nm, 340 nm and 380 nm. S was calculated from the interpolated lines
shown on the graph.
 
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