J3.1
Micrometeorological measurement of gaseous mercury fluxes: Theory and Practice
Grant C. Edwards, University of Guelph, Guelph, ON, Canada; and P. E. Rasmussen, W. H. Schroeder, G. M. Dias, L. Halfpenny-Mitchell, R. J. Kemp, and D. M. Wallace
The understanding of the air-surface exchange of total gaseous mercury (TGM) is key to unravelling unknown aspects of the mercury cycle involving the atmospheric compartment. In the past the use of micrometeorological methods for the measurement of the flux of TGM has largely been technologically limited. Early attempts involved the use of gold trap based Bowen ratio or gradient approaches. These efforts met with limited success due to inconsistent trap characteristis and large variance in the associated analytical approaches. With the advent of the Tekran 2537A TGM vapour analyzer there has emerged several attempts to develop micrometeorological methods based on this analyzer. These include Bowen ratio, gradient and Relaxed Eddy accumulation. Over the past five years the authors have developed, debugged and applied a gradient micrometeteorological method based on the Tekran 2537A instrument. The method developed has advantages over other Tekran based methods in that it is designed to look at small or large footprints and has achieved flux detection limits on the order of 0.5 ng/m2/s. An extensive set of TGM flux data has been collected in the application of the method. The paper discussed the method designed in the context of the theorectical constraints imoposed by micrometorological theory. Data are presented to support the method design and from studies over various ideal and complex terrain types.
Joint Session 3, Plant/atmosphere chemical interactions: sources and sinks of chemical species (Joint with the Fourth Symp. Urban Environment, 12th Joint Conf. on the Applications of Air Pollution Meteorology with A&WMA, and 25th Conf. Agricultural & Forest Meterology; Cosponsored by the AMS STAC Committee on Atmospheric Chemistry)
Thursday, 23 May 2002, 8:15 AM-10:15 AM
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