FATE OF MERCURY IN THE ARCTIC Michael Evan ... - COGCI

Fate of Mercury in the Arctic 70
have described that ozone and GEM are simultaneously depleted and that their depletion are highly
correlated. The Station Nord data confirms this, see Figure 12., page 70, After the depletion period
some very high concentrations of GEM appeared with values up to above 2 ng/m 3 and in 2002 up to
4.5 ng/m 3 . In 2001, similar observations were made at Barrow (Lindberg et al. 2002, Appendix C).
The high values after a depletion event are attributed to re-emission of mercury to the atmosphere
(Lindberg et al., 2002). The interruption of the GEM time series at Station Nord in the middle of the
summer makes it difficult to further interpret the importance of re-emission at Station Nord.
GEM, ng/m 3
2
1.5
1
0.5
0
-0.5
y = 0.039x - 0.095
R 2 = 0.800
0 10 20 30 40 50 60
Ozone, ppbv
Figure 12. GEM against ozone concentrations at Station Nord, Northeast Greenland including
a regression line obtained by orthogonal regression analysis. Data was selected from Fig. 11
where at least 3 consecutive concentrations were decreasing on both ozone and GEM and the
initial GEM concentration was above 0.4 ng m -3 . Only data from 2000 and 2001 were used as
high concentrations in 2002 indicates the presence of other processes than in 2000 and 2001.
The R 2 of approximately 0.8 was typical for the 2000 and 2001 campaigns. From Skov et al.,
2003, submitted, Appendix C.