Gap filling strategies for long term energy flux data sets

Authors

Eva Falge, University of California, Berkeley
Dennis D. Baldocchi, University of California, BerkeleyFollow
Richard Olson, Oak Ridge National Laboratory, Environmental Science Division
Peter Anthoni, Oregon State University, Corvallis
Marc Aubinet, Unité de Physique, Faculté des Sciences Agronomiques de Gembloux, B-50 30 Gembloux, Belgium
Christian Bernhofer, Technische Universität Dresden, IHM Meteorologie, Pienner Str. 9, 01737 Tharandt, Germany
George Burba, University of Nebraska-LincolnFollow
Reinhart Ceulemans, Laboratory of Plant Ecology, Department of Biology, University of Antwerpen, Universiteitsplein 1, B-2610 Wilrijk, Antwerp, Belgium
Robert Clement, Institute of Ecology and Resource Management, University of Edinburgh, Edinburgh EH9 3JU, UK
Han Dolman, Alterra, Postbus 47, 6700 AA Wageningen, The Netherlands
Andre Granier, INRA, Unité d’Ecophysiologie Forestière, F-54280 Champenoux, France
Patrick Gross, INRA, Unité d’Ecophysiologie Forestière, F-54280 Champenoux, France
Thomas Grunwald, Technische Universität Dresden, IHM Meteorologie, Pienner Str. 9, 01737 Tharandt, Germany
David Hollinger, USDA Forest Service
Niels-Otto Jensen, Risoe National Laboratory, Plant Biology and Biogeochemistry Department, P.O. Box 49, DK-4000 Roskilde, Denmark
Gabriel Katul, Duke University, Durham, NC 27708-0328, USA
Petri Keronen, University of Helsinki, FIN-00014 Helsinki, Finland
Andrew Kowalski, Laboratory of Plant Ecology, Department of Biology, University of Antwerpen, Universiteitsplein 1, B-2610 Wilrijk, Antwerp, Belgium
Chun Ta Lai, School of the Environment, Box 90328, Duke University, Durham, NC 27708-0328, USA
Beverly E. Law, Oregon State UniversityFollow
Tilden Meyers, NOAA/ATDD, 456 S. Illinois Avenue, Oak Ridge, TN 37831-2456, USA
John Moncrieff, Institute of Ecology and Resource Management, University of Edinburgh, Edinburgh EH9 3JU, UK
Eddy Moors, Alterra, Postbus 47, 6700 AA Wageningen, The Netherlands
J. William Munger, Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St., Cambridge, MA 02138, USA
Kim Pilegaard, Risoe National Laboratory, Plant Biology and Biogeochemistry Department, P.O. Box 49, DK-4000 Roskilde, Denmark
Ullar Rannik, University of Helsinki, FIN-00014 Helsinki, Finland
Corinna Rebmann, Max-Planck-Institut für Biogeochemie, Tatzendpromenade 1a, 07701 Jena, Germany
Andrew E. Suyker, University of Nebraska - LincolnFollow
John Tenhunen, Pflanzenökologie, Universität Bayreuth, 95440 Bayreuth, Germany
Kevin Tu, Department of Natural Resources, University of New Hampshire, Durham, NH 03824, USA
Shashi Verma, University of Nebraska - LincolnFollow
Timo Vesala, Department of Physics, P.O. Box 9, University of Helsinki, FIN-00014 Helsinki, Finland
Kell Wilson, NOAA/ATDD, 456 S. Illinois Avenue, Oak Ridge, TN 37831-2456, USA
Steve Wofsy, Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St., Cambridge, MA 02138, USA

Document Type

Article

Date of this Version

2-8-2001

Comments

Published in Agricultural and Forest Meteorology 107 (2001) 71–77.

Abstract

At present a network of over 100 field sites are measuring carbon dioxide, water vapor and sensible heat fluxes between the biosphere and atmosphere, on a nearly continuous basis. Gaps in the long term measurements of evaporation and sensible heat flux must be filled before these data can be used for hydrological and meteorological applications. We adapted methods of gap filling for NEE (net ecosystem exchange of carbon) to energy fluxes and applied them to data sets available from the EUROFLUX and AmeriFlux eddy covariance databases. The average data coverage for the sites selected was 69% and 75% for latent heat (λE) and sensible heat (H). The methods were based on mean diurnal variations (half-hourly binned means of fluxes based on previous and subsequent days, MDV) and look-up tables for fluxes during assorted meteorological conditions (LookUp), and the impact of different gap filling methods on the annual sum of λE and H is investigated. The difference between annual λE filled by MDV and λE filled by LookUp ranged from −120 to 210 MJm⁻² per year, i.e. −48 to +86mm per year, or −13 to +39% of the annual sum. For annual sums of H differences between −140 and +140 MJm⁻² per year or −12 to +19% of the annual sum were found.