caa a22 4500 44537263X CHVBK 20180317142952.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s00340-010-4307-0 doi (NATIONALLICENCE)springer-10.1007/s00340-010-4307-0 A new low-power, open-path instrument for measuring methane flux by eddy covariance [Elektronische Daten] [D. McDermitt, G. Burba, L. Xu, T. Anderson, A. Komissarov, B. Riensche, J. Schedlbauer, G. Starr, D. Zona, W. Oechel, S. Oberbauer, S. Hastings] This paper describes a new low-power instrument for measuring methane flux by eddy covariance method at sites without grid power. Design and field performance of the LI-7700 Methane Analyzer (LI-COR Biosciences) are examined in this study. The instrument uses 8W of power in steady-state operation and employs a tunable diode laser in an open Herriott cell configuration with 0.47m base path and 30m optical path length. Methane number density is measured using wavelength modulation spectroscopy (WMS) with 2f detection. Typical signal noise is <5ppb rms at 10Hz. Corrections for variations in temperature, pressure and water vapor are described. Data losses due to mirror contamination and condensation are minimized by a radiation shield and automatic mirror cleaning system and are shown to be small. Measured spectra and co-spectra are shown to follow the Kaimal model at deployment sites meeting classical criteria, and to follow sensible heat flux co-spectra from the sonic anemometer in most other cases, including difficult ones. Measured fluxes are similar in magnitude to those expected from the literature, and zero flux was measured during both summer and winter at a site known to have fluxes at or very near zero. Springer-Verlag, 2010 McDermitt D. LI-COR Biosciences, Lincoln, NE, USA aut Burba G. LI-COR Biosciences, Lincoln, NE, USA aut Xu L. LI-COR Biosciences, Lincoln, NE, USA aut Anderson T. LI-COR Biosciences, Lincoln, NE, USA aut Komissarov A. LI-COR Biosciences, Lincoln, NE, USA aut Riensche B. LI-COR Biosciences, Lincoln, NE, USA aut Schedlbauer J. West Chester University, West Chester, PA, USA aut Starr G. University of Alabama, Tuscaloosa, AL, USA aut Zona D. University of Antwerp, Wilrijk, Belgium aut Oechel W. San Diego State University, San Diego, CA, USA aut Oberbauer S. Florida International University, Miami, FL, USA aut Hastings S. Polar Field Services Inc., Barrow, AK, USA aut Applied Physics B Springer-Verlag 102/2(2011-02-01), 391-405 0946-2171 102:2<391 2011 102 340 https://doi.org/10.1007/s00340-010-4307-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00340-010-4307-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- McDermitt D. LI-COR Biosciences, Lincoln, NE, USA aut NATIONALLICENCE 700 1- Burba G. LI-COR Biosciences, Lincoln, NE, USA aut NATIONALLICENCE 700 1- Xu L. LI-COR Biosciences, Lincoln, NE, USA aut NATIONALLICENCE 700 1- Anderson T. LI-COR Biosciences, Lincoln, NE, USA aut NATIONALLICENCE 700 1- Komissarov A. LI-COR Biosciences, Lincoln, NE, USA aut NATIONALLICENCE 700 1- Riensche B. LI-COR Biosciences, Lincoln, NE, USA aut NATIONALLICENCE 700 1- Schedlbauer J. West Chester University, West Chester, PA, USA aut NATIONALLICENCE 700 1- Starr G. University of Alabama, Tuscaloosa, AL, USA aut NATIONALLICENCE 700 1- Zona D. University of Antwerp, Wilrijk, Belgium aut NATIONALLICENCE 700 1- Oechel W. San Diego State University, San Diego, CA, USA aut NATIONALLICENCE 700 1- Oberbauer S. Florida International University, Miami, FL, USA aut NATIONALLICENCE 700 1- Hastings S. Polar Field Services Inc., Barrow, AK, USA aut NATIONALLICENCE 773 0- Applied Physics B Springer-Verlag 102/2(2011-02-01), 391-405 0946-2171 102:2<391 2011 102 340 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer