Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 2 4 2005 10.5194/bg-2-353-2005 http://www.biogeosciences.net/2/353/2005/ http://www.biogeosciences.net/2/353/2005/bg-2-353-2005.html http://www.biogeosciences.net/2/353/2005/bg-2-353-2005.pdf 353 375 2005-12-05 Inventories of N₂O and NO emissions from European forest soils M. Kesik P. Ambus R. Baritz N. Brüggemann K. Butterbach-Bahl M. Damm J. Duyzer L. Horváth R. Kiese B. Kitzler A. Leip C. Li M. Pihlatie K. Pilegaard S. Seufert D. Simpson U. Skiba G. Smiatek T. Vesala S. Zechmeister-Boltenstern Karlsruhe Research Centre, Institute for Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Kreuzeckbahnstr. 19, 82 467 Garmisch-Partenkirchen, Germany Risoe National Laboratory, Department for Plant Biology and Biogeochemistry, Risø, Denmark Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany The Netherlands Organization for Applied Scientific Research, Apeldoorn, Netherlands Hungarian Meteorological Service, Department for Analysis of Atmospheric Environment, Budapest, Hungary Federal Forest Research Centre, Institute for Forest Ecology and Soil, Soil Biology, Vienna, Austria Commission of the European Communities, Environmental Institute, JRC Ispra, Italy Institute for the Study of Earth, Oceans and Space, Univ. of New Hampshire, Durham, USA University of Helsinki, Department of Physical Sciences, Helsinki, Finland Norwegian Meteorology Institute, Oslo, Norway Natural Environment Research Council, Centre for Ecology and Hydrology, Edinburgh, UK Forest soils are a significant source for the primary and secondary greenhouse gases N₂O and NO. However, current estimates are still uncertain due to the still limited number of field measurements and the herein observed pronounced variability of N trace gas fluxes in space and time, which are due to the variation of environmental factors such as soil and vegetation properties or meteorological conditions. To overcome these problems we further developed a process-oriented model, the PnET-N-DNDC model, which simulates the N trace gas exchange on the basis of the processes involved in production, consumption and emission of N trace gases. This model was validated against field observations of N trace gas fluxes from 19 sites obtained within the EU project NOFRETETE, and shown to perform well for N₂O (r²=0.68, slope=0.76) and NO (r²=0.78, slope=0.73). For the calculation of a European-wide emission inventory we linked the model to a detailed, regionally and temporally resolved database, comprising climatic properties (daily resolution), and soil parameters, and information on forest areas and types for the years 1990, 1995 and 2000. Our calculations show that N trace gas fluxes from forest soils may vary substantial from year to year and that distinct regional patterns can be observed. Our central estimate of NO emissions from forest soils in the EU amounts to 98.4, 84.9 and 99.2 kt N yr^&minus;1, using meteorology from 1990, 1995 and year 2000, respectively. This is &lt;1.0% of pyrogenic NO_x emissions. For N₂O emissions the central estimates were 86.8, 77.6 and 81.6 kt N yr^&minus;1, respectively, which is approx.&nbsp;14.5% of the source strength coming from agricultural soils. An extensive sensitivity analysis was conducted which showed a range in emissions from 44.4 to 254.0 kt N yr^&minus;1 for NO and 50.7 to 96.9 kt N yr^&minus;1 for N₂O, for year 2000 meteorology. <br /><br /> The results show that process-oriented models coupled to a GIS are useful tools for the calculation of regional, national, or global inventories of biogenic N trace gas emissions from soils. This work represents the most comprehensive effort to date to simulate NO and N₂O emissions from European forest soils.