References

ACP

Atmospheric Chemistry and Physics

ACP

Atmos. Chem. Phys.

1680-7324

Copernicus Publications

Göttingen, Germany

10.5194/acp-8-431-2008

A compact and stable eddy covariance set-up for methane measurements using off-axis integrated cavity output spectroscopy

Hendriks

D. M. D.

¹ Dolman

A. J.

¹ van der Molen

M. K.

¹ van Huissteden

Vrije Universiteit Amsterdam, Faculty of Earth and Life Sciences Department of Hydrology and Geo-environmental Sciences De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands

31 01 2008

8 2 431 443

2008

This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Generic License. To view a copy of this licence, visit https://creativecommons.org/licenses/by-nc-sa/2.5/

This article is available from https://acp.copernicus.org/articles/8/431/2008/acp-8-431-2008.html

The full text article is available as a PDF file from https://acp.copernicus.org/articles/8/431/2008/acp-8-431-2008.pdf

A Fast Methane Analyzer (FMA) is assessed for its applicability in a closed path eddy covariance field set-up in a peat meadow. The FMA uses off-axis integrated cavity output spectroscopy combined with a highly specific narrow band laser for the detection of CH4 and strongly reflective mirrors to obtain a laser path length of 2–20×103 m. Statistical testing and a calibration experiment showed high precision (7.8×10−3 ppb) and accuracy (<0.30%) of the instrument, while no drift was observed. The instrument response time was determined to be 0.10 s. In the field set-up, the FMA is attached to a scroll pump and combined with a 3-axis ultrasonic anemometer and an open path infrared gas analyzer for measurements of carbon dioxide and water vapour. The power-spectra and co-spectra of the instruments were satisfactory for 10 Hz sampling rates. Due to erroneous measurements, spikes and periods of low turbulence the data series consisted for 26% of gaps. Observed CH4 fluxes consisted mainly of emission, showed a diurnal cycle, but were rather variable over. The average CH4 emission was 29.7 nmol m−2 s−1, while the typical maximum CH4 emission was approximately 80.0 nmol m−2 s−1 and the typical minimum flux was approximately 0.0 nmol m−2 s−1. The correspondence of the measurements with flux chamber measurements in the footprint was good and the observed CH4 emission rates were comparable with eddy covariance CH4 measurements in other peat areas. Additionally, three measurement techniques with lower sampling frequencies were simulated, which might give the possibility to measure CH4 fluxes without an external pump and save energy. Disjunct eddy covariance appeared to be the most reliable substitute for 10 Hz eddy covariance, while relaxed eddy accumulation gave reliable estimates of the fluxes over periods in the order of days or weeks.

References 1

Allan, D. W.: Statistics of Atomic Frequency Standards, Proceedings of the Institute of Electrical and Electronics Engineers, 54(2), 221–230, 1966.

Aubinet, M., Grelle A., Ibrom, A., et al.: Estimates of the annual net carbon and water exchange of forests: The EUROFLUX methodology, Adv. Ecol. Res., 30, 113–175, 2000.

Bear, D. S., Paul, J. B., Gupta, M., et al.: Sensitive absorption measurements in the near-infrared region using off-axis integrated-cavity-output spectroscopy, Appl. Phys. B, 75, 261–265, 2002.

Bowling, D. R., Delany, A. C., Turnipseed, A. A., et al.: Modification of the relaxed eddy accumulation technique to maximize measured scalar mixing ratio differences in updrafts and downdrafts, J. Geophys. Res.-Atmos., 104(D8), 9121–9133, 1999.

Businger, J. A. and Oncley, S. P.: Flux Measurement with Conditional Sampling, Journal of Atmospheric and Oceanic Technology, 7(2), 349–352, 1990.

Dolman, A. J., Maximov, T. C., Moors, E. J., et al.: Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (Larix cajanderii) on permafrost, Biogeosciences, 1, 133–146, 2004.

Drösler, M., Freibauer, A., Christensen, T. R., et al.: Observation and status of peatland greenhouse gas emission in Europe, in: The Continental-Scale Greenhouse Gas Balance of Europe, edited by: Dolman, H., Valentini, R., Freibauer, A., Series: Ecological Studies, Vol 203, 305 pp., ISBN 978-0-387-76568-6, 237–255, 2008.

Eisma, R., Vermeulen, A. T., and Kieskamp, W. M.: Determination of European methane emissions, using concentration and isotope measurements, Environ. Monit. Assess., 31, 197–202, 1994.

Faist, J., Capasso, F., Sivco, D. L., et al.: Quantum Cascade Laser - Temperature-Dependence of the Performance-Characteristics and High T0 Operation, Appl. Phys. Lett., 65(23), 2901–2903, 1994.

Foster, P., Ramaswamy, V., Artaxo, P., et al.: Changes in Atmospheric Constituents and in Radiative Forcing, in: Climate Change 2007: The Physical Science Basis, Contribution of working group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin., D., Manning, M., et al., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2007.

Gash, J. H. C. and Dolman, A. J.: Sonic anemometer (co)sine response and flux measurement I. The potential for (co)sine error to affect sonic anemometer-based flux measurements, Agr. Forest Meteorol., 119(3–4), 195–207, 2003.

Graus, M., Hansel, A., Wisthaler, A., et al.: A relaxed-eddy-accumulation method for the measurement of isoprenoid canopy-fluxes using an online gas-chromatographic technique and PTR-MS simultaneously, Atmos. Environ., 40, S43–S54, 2006.

Hargreaves, K. J., Fowler, D., Pitcairn, C. E. R., et al.: Annual methane emission from Finnish mires estimated from eddy covariance campaign measurements, Theor. Appl. Climatol., 70(1–4), 203–213, 2001.

Hendriks, D. M. D., van Huissteden, J., Dolman, A. J., and van der Molen, M. K.: The full greenhouse gas balance of an abandoned peat meadow, Biogeosciences, 4, 411–424, 2007.

Højstrup, J.: A simple model for the adjustment of velocity spectra in unstable conditions downstream of an abrupt change in roughness and heat flux, Bound.-Lay. Meteorol., 21, 341–356, 1981.

Kaimal, J. C. and Finnigan, J. J.: Atmospheric boundary layer flows, their structure and management, New York, Oxford University Press, 1994.

Kaimal, J. C., Wyngaard, J. C., Haugen, D. A., et al.: Turbulence structure in convective boundary-layer, J. Atmos., 33(11), 2152–2169, 1976.

Kaimal, J. C., Izumi, Y, Wyngaard, J. C., et al.: Spectral characteristics of surface-layer turbulence, Q. J. Roy. Meteor. Soc., 98(417), 563–589, 1972.

Kormann, R., Muller, H., and Werle, P.: Eddy flux measurements of methane over the fen "Murnauer Moos", 11 degrees 11´ E, 47 degrees 39´ N, using a fast tunable diode laser spectrometer, Atmos. Environ., 35(14), 2533–2544, 2001.

Kroon, P. S., Hensen, A., Zahniser, M. S., et al.: Suitability of quantum cascade laser spectrometry for CH4 and N2O eddy covariance measurements, Biogeosciences, 4, 715–728, 2007.

Kuhn, U., Dindorf, T., Ammann, C., et al.: Design and field application of an automated cartridge sampler for VOC concentration and flux measurements, J. Environ. Monitor., 7(6), 568–576, 2005.

Leuning, R. and Moncrieff, J.: Eddy-Covariance CO2 Flux Measurements Using Open-Path and Closed-Path CO2 Analyzers – Corrections for Analyzer Water-Vapour Sensitivity and Damping of Fluctuations in Air Sampling Tubes, Bound.-Lay. Meteorol., 53(1–2), 63–76, 1990.

Leuning, R. and King, K. M.: Comparison of eddy-covariance measurements of CO2 fluxes by open-path and closed path CO2 analyzers, Bound.-Lay. Meteorol., 59(3), 297–311, 1992.

Lloyd, C. R., Bessemoulin, P., Cropley, F. D., et al.: A comparison of surface fluxes at the HAPEX-Sahel fallow bush sites, J. Hydrol., 189(1–4), 400–425, 1997.

Moore, C. J.: Frequency response corrections for eddy-correlation systems, Bound.-Lay. Meteorol., 37(1–2), 17–35, 1986.

Nakai, T., van der Molen, M. K., Gash, J. H. C., et al.: Correction of sonic anemometer angle of attack errors, Agr. Forest Meteorol., 136(1–2), 19–30, 2006.

Nelson, D. D., McManus, B., Urbanski, S., et al.: High precision measurements of atmospheric nitrous oxide and methane using thermoelectrically cooled mid-infrared quantum cascade lasers and detectors, Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy, 60(14), 3325–3335, 2004.

O'Keefe, A.: Integrated cavity output analysis of ultra-weak absorption, Chemi. Phys. Lett., 293(5–6), 331–336, 1998.

Pattey, E., Desjardins, R. L., and Rochette, P.: Accuracy of the Relaxed Eddy-Accumulation Technique, Evaluated Using CO2 Flux Measurements, Bound.-Lay. Meteorol., 66(4), 341–355, 1993.

Rinne, H. J. I., Delany, A. C., Greenberg, J. P., et al.: A true eddy accumulation system for trace gas fluxes using disjunct eddy sampling method, J. Geophys. Res.-Atmos., 105(D20), 24 791–24 798, 2000.

Rinne, H. J. I., Guenther, A. B., Warneke, C., et al.: Disjunct eddy covariance technique for trace gas flux measurements, Geophys. Res. Lett., 28(16), 3139–3142, 2001.

Smeets, C. J. P. P., Duynkerke, P. G., and Vugts, H. F.: Turbulence characteristics of the stable boundary layer over a mid-latitude glacier. Part I: A combination of katabatic and large-scale forcing, Bound.-Lay. Meteorol., 87(1), 117–145, 1998.

Stull, R. B.: An Introduction to boundary layer meteorology, Dordrecht, Kluwer Academic Publishers, Atmospheric Sciences Library, Chapter 8, 1988.

Van der Molen, M. K.: Meteorological impacts of land use change in the Maritime tropics, Chapter 3, Data analysis, Thesis, Vrije Universiteit, 35–72, 2002.

Van der Molen, M. K., Gash, J. H. C., Elbers, J. A., et al.: Sonic anemometer (co)sine response and flux measurement – II. The effect of introducing an angle of attack dependent calibration, Agr. Forest Meteorol., 122(1–2), 95–109, 2004.

Van der Molen, M. K., Zeeman, M. J., Lebis, J., et al.: EClog: A handheld eddy covariance logging system, Comput. Electron. Agr., 51(1–2), 110–114, 2006.

Verma, S. B., Ullman, F. G., Billesbach, D., et al.: Eddy correlation measurements of methane flux in a northern peatland ecosystem. Bound.-Lay. Meteorol., 58, 289–304, 1992.

Werle, P., Mucke, R., and Slemr, F.: The Limits of Signal Averaging in Atmospheric Trace-Gas Monitoring by Tunable Diode-Laser Absorption-Spectroscopy (Tdlas), Appl. Phys. B-Photo., 57(2), 131–139, 1993.

Wohlfahrt, G., Anfang, C., Bahn, M., et al.: Quantifying nighttime ecosystem respiration of a meadow using eddy covariance, chambers and modelling, Agr. Forest Meteorol., 128(3–4), 141–162, 2005.

Zahniser, M. S., Nelson, D. D., McManus, J. B., et al.: Measurement of Trace Gas Fluxes Using Tunable Diode-Laser Spectroscopy, Philosophical Transactions of the Royal Society of London Series a-Mathematical Physical and Engineering Sciences, 351(1696), 371–381, 1995.