A dual-inlet, single detector relaxed eddy accumulation system for long-term measurement of mercury flux
JournalArticle (Originalarbeit in einer wissenschaftlichen Zeitschrift)
ID 3645270
Author(s) Osterwalder, Stefan; Fritsche, Johannes; Alewell, Christine; Schmutz, Michael; Nilsson, Mats; Jocher, Georg; Sommar, Jonas; Rinne, Janne; Bishop, Kevin
Author(s) at UniBasel Alewell, Christine
Schmutz, Michael
Osterwalder, Stefan
Year 2016
Title A dual-inlet, single detector relaxed eddy accumulation system for long-term measurement of mercury flux
Journal Atmospheric Measurement Techniques
Volume 9
Number 2
Pages / Article-Number 509-524
Abstract The fate of anthropogenic emissions of mercury (Hg) to the atmosphere is influenced by the exchange of elemental Hg with the earth surface. This exchange holds the key to a better understanding of Hg cycling from local to global scales, which has been difficult to quantify. To advance research about land-atmosphere Hg interactions, we developed a dual-inlet, single detector relaxed eddy accumulation ( REA ) system. REA is an established technique for measuring turbulent fluxes of trace gases and aerosol particles in the atmospheric surface layer. Accurate determination of gaseous elemental mercury (GEM) fluxes has proven difficult due to technical challenges presented by extremely small concentration differences (typically < 0.5 ngm(-3)) between updrafts and downdrafts. We present an advanced REA design that uses two inlets and two pairs of gold cartridges for continuous monitoring of GEM fluxes. This setup reduces the major uncertainty created by the sequential sampling in many previous designs. Additionally, the instrument is equipped with a GEM reference gas generator that monitors drift and recovery rates. These innovations facilitate continuous, autonomous measurement of GEM flux. To demonstrate the system performance, we present results from field campaigns in two contrasting environments: an urban setting with a heterogeneous fetch and a boreal peatland during snowmelt. The observed average emission rates were 15 and 3 n gm(-2) h(-1), respectively. We believe that this dual-inlet, single detector approach is a significant improvement of the REA system for ultra-trace gases and can help to advance our understanding of long-term land-atmosphere GEM exchange.
Publisher European Geosciences Union
ISSN/ISBN 1867-1381 ; 1867-8548
edoc-URL http://edoc.unibas.ch/44565/
Full Text on edoc No
Digital Object Identifier DOI 10.5194/amt-9-509-2016
ISI-Number WOS:000375612000012
Document type (ISI) Article

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