Abstract
To assess annual budgets of CO2 exchange betweenthe biosphere and atmosphere over representativeecosystems, long-term measurements must be made overecosystems that do not exist on ideal terrain. How tointerpret eddy covariance measurements correctlyremains a major task. At present, net ecosystemCO2 exchange is assessed, by members of themicrometeorological community, as the sum of eddycovariance measurements and the storage of CO2 inthe underlying air. This approach, however, seemsunsatisfactory as numerous investigators are reportingthat it may be causing nocturnal respiration fluxdensities to be underestimated.
A new theory was recently published by Lee (1998, Agricultural and Forest Meteorology91: 39–50) for assessing net ecosystem-atmosphere CO2 exchange(Ne) over non-ideal terrain. Itincludes a vertical advection term. We apply thisequation over a temperate broadleaved forest growingin undulating terrain. Inclusion of the verticaladvection term yields hourly, daily and annual sums ofnet ecosystem CO2 exchange that are moreecologically correct during the growing season.During the winter dormant period, on the other hand,corrected CO2 flux density measurements of anactively respiring forest were near zero. Thisobservation is unrealistic compared to chambermeasurements and model calculations. Only duringmidday, when the atmosphere is well-mixed, domeasurements of Ne match estimatesbased on model calculations and chamber measurements. On an annual basis, sums of Newithout the advection correction were 40% too large,as compared with computations derived from a validatedand process-based model. With the inclusion of theadvection correction term, we observe convergencebetween measured and calculated values ofNe on hourly, daily and yearly time scales. We cannot, however, conclude that inclusion of aone-dimensional, vertical advection term into thecontinuity equation is sufficient for evaluatingCO2 exchange over tall forests in complexterrain. There is an indication that the neglected term,ū(∂ c¯/∂ x), isnon-zero and that CO2 may be leakingfrom the sides of the control volume during the winter. In this circumstance, forest floor CO2 effluxdensities exceed effluxes measured above the canopy.
Similar content being viewed by others
References
Aubinet, M., Grelle, A., Ibrom, A., Rannik, U., Moncrieff, J., Foken, T., Kowalski, P., Martin, P., Berbigier, P., Bernhofer, Ch., Clement, R., Elbers, J., Granier, A., Grunwald, T., Morgenster, K., Pilegaard, K., Rebmann, C., Snijders, W., Valentini, R., and Vesala, T.: 2000, 'Estimates of the Annual Net Carbon and Water Exchange of European Forests: The EUROFLUX Methodology', Adv. Ecol. Res.30, 113–174.
Auble, D. and Meyers, T. P.: 1992, 'An Open Path, Fast Response Infrared Absorption Gas Analyzer for H2O and CO2', Boundary-Layer Meteorol.59, 243–256.
Avissar, R. and Pielke, R. A.: 1989, 'A Parameterization of Heterogeneous Land Surfaces for Atmospheric Numerical Models and its Impact on Regional Meteorology', Mon. Wea. Rev.117, 2113–2136.
Baldocchi, D. D.: 1997, 'Measuring and Modeling Carbon Dioxide and Water Vapor Exchange over a Temperate Broad-Leaved Forest during the 1995 Summer Drought', Plant Cell Environ.20, 1108–1122.
Baldocchi, D. D. and Meyers, T. P.: 1991, 'Trace Gas Exchange at the Floor of a Deciduous Forest: I. Evaporation and CO2 Efflux', J. Geophys. Res.96, 7271–7285.
Baldocchi, D. D and Meyers, T. P.: 1998, 'On Using Eco-Physiological, Micrometeorological and Biogeochemical Theory to Evaluate Carbon Dioxide, Water Vapor and Gaseous Deposition Fluxes over Vegetation', Agric. For. Meteorol.90, 1–26.
Baldocchi, D. D., Hicks, B. B., and Meyers, T. P.: 1988, 'Measuring Biosphere-Atmosphere Exchanges of Biologically Related Gases with Micrometeorological Methods', Ecology69, 1331–1340.
Baldocchi, D. D., Valentini, V., Running, S. R., Oechel, W., and Dahlman, R.: 1996, 'Strategies for Measuring and Modelling CO2 and Water Vapor Fluxes over Terrestrial Ecosystems', Global Change Biol.2, 159–168.
Bink, N. J.: 1996, The Structure of the Atmospheric Surface Layer Subject to Local Advection, Ph.D. Thesis. Agricultural University, Wageningen, The Netherlands.
Black, T. A., den Hartog, G., Neumann, H., Blanken, P., Yang, P., Nesic, Z., Chen, S., Russel, C., Voroney, P., and Staebler, R.: 1996, 'Annual Cycles of CO2 and Water Vapor Fluxes above and within a Boreal Aspen Stand', Global Change Biol.2, 219–230.
Canadell, J., Mooney, H., Baldocchi, D.,. Berry, J., Ehleringer, J., Field, C., Gower, T., Hollinger, D., Hunt, J., Jackson, R., Running, S., Shaver, G., Trumbore, S., Valentini, R., and Yoder, B.: 2000, 'Carbon Metabolism of the Terrestrial Biosphere', Ecosystems, in press.
Chambers, M. L. S.: 1998, Characterization of Forest Floor Carbon Dioxide Efflux from Three Forest Ecosystems in East Tennessee, U.S.A., Masters Thesis, University of Tennessee, Knoxville, TN, 159 pp.
Chen, W. J., Black, T. A., Yang, P. C., Barr, A. G., Neumann, H. H., Nesic, Z., Blanken, P. D., Novak, M. D., Eley, J., Ketler, R. J., and Cuenca, R.: 1999. 'Effects of Climatic Variability on the Annual Carbon Sequestration by a Boreal Aspen Forest', Global Change Biol.5, 41–54.
Edwards, N. T., Johnson, D. W., McLaughlin, S. B., and Harris, W. F.: 1989. 'Carbon Dynamics and Productivity', in J. W. Johnson and R. I. van Hook (eds.), Analysis of Biogeochemical Cycling Processes in Walker Branch Watershed, Springer-Verlag, New York, NY, pp. 197–232.
Fan, S. M., Gloor, M., Mahlman, J., Pacala, S., Sarmiento, J., Takahashi, T., and Tans, P.: 1998, 'A Large Terrestrial Carbon Sink in North America Implied by Atmospheric and Oceanic Carbon Dioxide Data and Models', Science282, 442–446.
Foken, Th. and Wichura, B.: 1995, 'Tools for Quality Assessment of Surface-Based Flux Measurements', Agric. For. Meteorol.78, 83–105.
Goulden, M. L., Munger, J. W., Fan, S. M. Daube, B. C., and Wofsy, S. C.: 1996a, 'Exchange of Carbon Dioxide by a Deciduous Forest: Response to Interannual Climate Variability', Science271, 1576–1578.
Goulden, M. L., Munger, J. W., Fan, S. M. Daube, B. C., and Wofsy, S. C. 1996b, 'Measurement of Carbon Storage by Long-Term Eddy Correlation: Methods and a Critical Assessment of Accuracy', Global Change Biol.2, 169–182.
Goulden, M. L., Wofsy, S. C., Harden, J. W., Trumbore, S. E., Crill, P. M., Gower, S. T., Fires, T., Daube, B. C., Fan, S. M., Sutton, D. J., Bazzaz, A., and Munger, J. W.: 1998, 'Sensitivity of Boreal Forest Carbon Balance to Soil Thaw', Science279, 214–217.
Greco, S. and Baldocchi, D. D.: 1996, 'Seasonal Variations of CO2 and Water Vapour Exchange Rates over a Temperate Deciduous Forest', Global Change Biol.2, 183–198.
Hanson, P. J., Wullschleger, S. D., Bohlman, S. A., and Todd, D. E.: 1993. 'Seasonal and Topographic Patterns of Forest Floor CO2 Efflux from an Upland Oak Forest', Tree Physiol.13, 1–15.
Harley, P. C. and Baldocchi, D. D.: 1995, 'Scaling Carbon Dioxide and Water Vapor Exchange from Leaf to Canopy in a Deciduous Forest: Leaf Level Parameterization', Plant Cell Environ.18, 1146–1156.
Heimann, M., Keeling, C. D., and Fung, I.: 1986, 'Simulating the Atmospheric Carbon Dioxide Distribution with a Three Dimensional Tracer Model', in J. R. Trabalka and D. E. Reichle (eds.), The Changing Carbon Cycle: A Global Analysis, Springer-Verlag, pp. 16–49.
Hollinger, D. Y. and Wofsy, S. C.: 1997, 'Science Plan for AmeriFlux: Long-Term Flux Measurement Network of the Americas', http://www.esd.ornl.gov/programs/NIGEC/scif.htm
Hutchison, B. A. and Baldocchi, D. D.: 1989, 'Forest Meteorology', in D. W. Johnson and R. I. Van Hook (eds.), Analysis of Biogeochemical Cycling Processes in Walker Branch Watershed, Springer-Verlag, pp. 21–95.
Jarvis, P. G., Massheder, J., Hale, S., Moncrieff, J., Rayment, M., and Scott, S.: 1997, 'Seasonal Variation of Carbon Dioxide, Water Vapor and Energy Exchanges of a Boreal Black Spruce Forest', J. Geophys. Res.102, 28953–28967.
Kaimal, J. C. and Finnigan, J. J.: 1994, Atmospheric Boundary Layer Flows: Their Structure and Measurement, Oxford University Press, Oxford, U.K., 289 pp.
Lavigne, M. B., Ryan, M. G., Anderson, D. E., Baldocchi, D. D., Crill, P. M., Fitzjarrald, D. R., Goulden, M. L., Gower, S. T., Massheder, J. M., McCauhey, J. H., Rayment, M., and Striegl, R. G.: 1997, 'Comparing Nocturnal Eddy Covariance Measurements to Estimates of Ecosystem Respiration Made by Scaling Chamber Measurements', J. Geophys. Res.102, 28977–28986.
Lee, X.: 1998, 'On Micrometeorological Observations of Surface-Air Exchange over Tall Vegetation', Agric. For. Meteorol.91, 39–50.
Lee, X. H., Black, T. A., den Hartog, G., Neumann, H., Nesic, Z., and Olejnik, J.: 1996, 'Carbon Dioxide Exchange and Nocturnal Processes over a Mixed Deciduous Forest', Agric. For. Meteorol.81, 13–29.
Lindroth, A., Grelle, A., and Moren, A. S.: 1998, 'Long-Term Measurements of Boreal Forest Carbon Balance Reveal Large Temperature Sensitivity', Global Change Biol.4, 443–450.
McMillen, R. T. 1988. 'An Eddy Correlation Technique with Extended Applicability to Non-Simple Terrain', Boundary-Layer Meteorol.43, 231–245.
Moncrieff, J. B., Mahli, Y., and Leuning, R.: 1996, 'The Propagation of Errors in Long Term Measurements of Land Atmosphere Fluxes of Carbon and Water', Global Change Biol.2, 231–240.
Mordukhovich, M. I. and Tsvang, L. R.: 1966, 'Direct Measurement of Turbulent Flows at Two Heights in the Atmospheric Ground Layer', Izvestia, Atmos. Oceanic Phys.2, 786–803.
Paw U, K. T., Baldocchi, D., Meyers, T., and Wilson, K.: 2000, 'Correction of Eddy Covariance Measurements Incorporating Both Advective Effects and Density Fluxes', Boundary-Layer Meteorol., in press.
Rannik, U.: 1998, 'On the Surface Layer Similarity at a Complex Forest Site', J. Geophys. Res.103, 8685–8697.
Rao, K. S., Wyngaard, J. C., and Cote, O. R.: 1974, 'Local Advection of Momentum, Heat, and Moisture in Micrometeorology', Boundary-Layer Meteorol.7, 331–348.
Raupach, M. R. and Finnigan, J. J.: 1997, 'The Influence of Topography on Meteorological Variables and Surface-Atmosphere Interactions', J. Hydrol.190, 182–213.
Raupach, M. R., Weng, W. S., Carruthers, D. J., and Hunt, J. C. R.: 1992, 'Temperature and Humidity Fields and Fluxes over Hills', Quart. J. Roy. Meteorol. Soc.118, 191–225.
Sun, J., Lenschow, D. H., Mahrt, L., Crawford, D. L., Davis, K. J., Oncley, S. P., MacPherson, J. I., Wang, Q., Dobosy, R. J., and Desjardins, R. L.: 1997, 'Lake-Induced Atmospheric Circulations during BOREAS', J. Geophys. Res.102, 29155–29166.
Tenhunen, J. D., Valentini, R., Kostner, B., Zimmermann, R., and Granier, A.: 1998, 'Variation in Forest Gas Exchange at Landscape to Continental Scales', Annales des Sciences Forestières55, 1–11.
Valentini, R. P. de Angelis, Matteucci, G., Monaco, R., Dore, S., and Scarascia-Mugnozza, G. E.: 1996, 'Seasonal Net Carbon Dioxide Exchange of a Beech Forest with the Atmosphere', Global Change Biol.2, 199–208.
Vermetten, A.W. M., Ganzeveld, L., Jeuken, A., Hofschreuder, P., and Mohren, G.M. J.: 1994, 'CO2 Uptake by a Stand of Douglas Fir: Flux Measurements Compared with Model Calculations', Agric. For. Meteorol.72, 57–80.
Webb, E. K., Pearman, G., and Leuning, R.: 1980, 'Correction of Flux Measurements for Density Effects Due To Heat and Water Vapor Transfer', Quart. J. Roy. Meteorol. Soc.106, 85–100.
Wesely, M. L.: 1970, Eddy Correlation Measurements in the Atmospheric Surface Layer over Agricultural Crops, Dissertation, University of Wisconsin, Madison, WI.
Wilson, K. B., Baldocchi, D. D., and Hanson, P. J.: 2000, 'Spatial and Seasonal Variability of Photosynthesis Parameters and their Relationship to Leaf Nitrogen in a Deciduous Forest', Tree Physiol., in press.
Wofsy, S. C, Goulden, M. L.,. Munger, J. W., Fan, S. M., Bakwin, P. S., Daube, B. C., Bassow, S. L., and Bazzaz, F. A.: 1993, 'Net Exchange of CO2 in a Mid-Latitude Forest', Science260, 1314–1317.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Baldocchi, D., Finnigan, J., Wilson, K. et al. On Measuring Net Ecosystem Carbon Exchange Over Tall Vegetation on Complex Terrain. Boundary-Layer Meteorology 96, 257–291 (2000). https://doi.org/10.1023/A:1002497616547
Published:
Issue Date:
DOI: https://doi.org/10.1023/A:1002497616547