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

Fate of Mercury in the Arctic 40
Therefore any REA system requires collection of the trace gas of interest over time. When
RGM is the trace gas of interest heated, KCl coated, annular denuders may be used as accumulators.
Collection and measurement of RGM was discussed in the previous section. This section will
present the measurement of the reactive gaseous mercury flux using the relaxed eddy accumulation
system and its components.
RGM flux measurements were performed from 29 March, 2001 through April 12, 2001, with
the system set up at approximately 3 m above the snow pack surface on a guy-wire support of the
NOAA, Barrow, CMDL tower, oriented into the prevailing winds, arriving from the Beaufort Sea.
The measurements were made using a micrometeorological flux measurement system built by
METSUPPORT aps, Denmark in January 2001 for this campaign. The system was designed in
consultation with this author and Dr. Skov, together with the Director of METSUPPORT, Dr. P.
Hummelshøj, with this new, Arctic application of REA in mind.
METSUPPORT dubbed the system the Mobile REA Data Acquisition System, Model 1005-02,
serial no. 10012, and shipped it directly to the author in Oak Ridge, where its components were
tested at NOAA, ATDD and Walker Branch, prior to shipping to Barrow.
This system was coupled with the Landis et al., 2002, annular denuder method for measuring
RGM, and the previously described heating caps, as the sampling front end.
The total system consists of 4 primary components:
1. The sampling end, consisting of three annular denuder sampling trains and associated
heating caps, with neoprene tubing running to the switches.
2. A METEK, Germany, model USA-1 heated, sonic anemometer, serial no. 2000 12
003/01 with a separate weather tight electronic box. The effect of the heating is 55 W,
sufficient to prevent rime ice build up under Arctic conditions. The sonic provides
airflow information as a 10 Hz serial data stream.