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Proceedings Paper

Tunable diode-laser-based measurements of a gas flux emanating from a two-dimensional surface
Author(s): Heather A Gamble; Yongsheng Feng; Xiaomei Li; Harold I. Schiff; Gervase I. Mackay
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Paper Abstract

Remote optical techniques are well suited for obtaining representative average values for gas fluxes emanating from a semi-infinite flat surface. Unisearch, the Alberta Reserach Council and the University of Alberta have developed a technique and methodology for making such measurements using a near-IR tunable diode laser analyzer and a set of open path optics. The technqiue uses the LasIR to measure gas concentrations at two different heights along paths which folow the perimeter of a square, flat surface. The measurements are used to calculate a concentration gradient across the height difference. These values, along with air temperature, relative humidity, soil heat flux, net radiation and wind speed/direction data, are then used to calculate the average flux emanating from the surface by applying an integrated flux gradient analysis based on Monin-Obukhov similarity theory. This method was applied to measure fluxes of methane emanating from a 50m × 50m test agricultural plot after the application of manure. Plans are underway to extend the capability of the system to measure up to four different species simultaneously.

Paper Details

Date Published: 17 February 2003
PDF: 10 pages
Proc. SPIE 4833, Applications of Photonic Technology 5, (17 February 2003); doi: 10.1117/12.474037
Show Author Affiliations
Heather A Gamble, Unisearch Associates Inc. (Canada)
Yongsheng Feng, Univ. of Alberta (Canada)
Xiaomei Li, Alberta Research Council Climate Change Technologies (Canada)
Harold I. Schiff, Unisearch Associates Inc. (Canada)
Gervase I. Mackay, Unisearch Associates Inc. (Canada)

Published in SPIE Proceedings Vol. 4833:
Applications of Photonic Technology 5

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