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A system for measuring methane fluxes from inland and coastal wetland environmentsA CH4 measuring system with a sensitivity of 0.01 ppmv and a response time of 1 sec is described. Pulses are separable from moving and stationary readings, the device floats, and air velocity in the chamber can be controlled in the range 0-4.4 m/sec. The system is set on the water so that controlled speed air from beneath can enter an inner chamber and be pumped through a gas filter correlation system (GFC) before being returned to the chamber. The GFC mechanism yields an absorption signal in the form of a dc voltage, which a processor orders printed on a strip chart as a function of time. Detection of the CH4 amounts is through IR absorption, and the sensitivity of the instrument has been measured at .002-.051 g/sq m per day with air flows in the range 0.90-4.40 m/sec. The unit can be modified to detect CO and CO2, and further applications for low plant canopies and land surfaces are indicated.
Document ID
19820043063
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Sebacher, D. I.
(NASA Langley Research Center Hampton, VA, United States)
Harriss, R. C.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 10, 2013
Publication Date
March 1, 1982
Publication Information
Publication: Journal of Environmental Quality
Volume: 11
Subject Category
Environment Pollution
Accession Number
82A26598
Distribution Limits
Public
Copyright
Other

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