greenhouse gas; process based biogeochemical model; stable isotope; nitrous oxide (N2O); Lagrangian particle dispersion model
Ibraim Erkan, Denk Tobias, Wolf Benjamin, Barthel Matti, Gasche Rainer, Wanek Wolfgang, Zhang Shasha, Kiese Ralf, Butterbach‐Bahl Klaus, Eggleston Sarah, Emmenegger Lukas, Six Johan, Mohn Joachim (2020), Denitrification Is the Main Nitrous Oxide Source Process in Grassland Soils According to Quasi‐Continuous Isotopocule Analysis and Biogeochemical Modeling, in
Global Biogeochemical Cycles, 34(6), e2019GB006.
Ibraim Erkan, Wolf Benjamin, Harris Eliza, Gasche Rainer, Wei Jing, Yu Longfei, Kiese Ralf, Eggleston Sarah, Butterbach-Bahl Klaus, Zeeman Matthias, Tuzson Béla, Emmenegger Lukas, Six Johan, Henne Stephan, Mohn Joachim (2019), Attribution of N2O sources in a grassland soil with laser spectroscopy based isotopocule analysis, in
Biogeosciences, 16(16), 3247-3266.
Ibraim Erkan, Harris Eliza, Eyer Simon, Tuzson Béla, Emmenegger Lukas, Six Johan, Mohn Joachim (2017), Development of a field-deployable method for simultaneous, real-time measurements of the four most abundant N2O isotopocules, in
Isotopes in Environmental and Health Studies, 54(1), 1-15.
Harris Eliza, Henne Stephan, Hüglin Christoph, Zellweger Christoph, Tuzson Béla, Ibraim Erkan, Emmenegger Lukas, Mohn Joachim (2017), Tracking nitrous oxide emission processes at a suburban site with semicontinuous, in situ measurements of isotopic composition suburban N2O isotopic composition, in
Journal of Geophysical Research: Atmospheres, 122(3), 1850-1870.
Denk Tobias R.A., Mohn Joachim, Decock Charlotte, Lewicka-Szczebak Dominika, Harris Eliza, Butterbach-Bahl Klaus, Kiese Ralf, Wolf Benjamin (2017), The nitrogen cycle: A review of isotope effects and isotope modeling approaches, in
Soil Biology and Biochemistry, 105, 121-137.
Nitrous oxide (N2O) is a potent greenhouse gas (GHG) and an important anthropogenic contributor to stratospheric ozone-depletion. Its atmospheric abundance increased significantly in recent decades due to the perturbation of the nitrogen cycle, mainly due to growing usage of mineral fertilizers and enhanced microbial production in soils. Process-oriented biogeochemical soil models are increasingly used to assess regional scale N2O budgets and to develop mitigation strategies. However, the validation strategies usually aim to minimize the uncertainty for total N2O emissions at site scale and, thus, the partitioning between specific microbial processes and the reliability of budgets at larger scales remains unclear. Microbial source processes of N2O, specifically nitrification and/ or denitrification, exhibit characteristic isotopic signatures that can be used to quantify individual N2O sources. However, these measurements have been scarce and limited to low-frequency flask sampling in combination with laboratory-based mass spectrometric analysis.The SNF - DFG Lead Agency project “N2O from the Swiss midlands: regional sources and hot spots”, initiated in 2014, aims to combine two complementary approaches: real-time top-down measurements of N2O concentrations with site-specific isotopic composition at heights of 12 m or lower (i.e., the atmospheric surface layer) and 212 m (i.e., the atmospheric boundary layer), and bottom-up biogeochemical modelling (LandscapeDNDC). During the first two years of the project, the following milestones have been successfully accomplished for the individual work packages:WP1 (Empa):- Development and validation of a measurement technique for N2O isotopologues with target precision of 0.1 ‰ for d15Na, d15Nb and d18O-N2O completed [E. Ibraim et al., IEHS, 2017].- Advancement of N2O isotopic analysis accuracy achieved by expanding the calibration scale to d18O-N2O.- Preparatory work at the Beromünster tall tower station (e.g., air conditioning) completed and first N2O concentration measurements executed.WP2 (KIT):- Review of N isotope effects published [T. Denk et al., SBB, 2017](KIT, Empa)- Based on the review, development and implementation of the isotope sub-module SIMONE into LandscapeDNDC and validation on available data at site scale (Chamau). WP3 (Empa): - High-resolution simulation (FLEXPART-COSMO1) of one-year footprint climatology for the Beromünster catchment to provide guidance for soil sampling strategy.- Simulations of atmospheric N2O concentrations and isotopic composition for a suburban site [E. Harris et al., JGR, 2017].In the presented 18 month extension project we will carry out one additional extended field campaign at site scale combining atmospheric measurements with simultaneous automatic and manual chamber measurements at adjacent grassland, arable and forest sites to enable a broader model validation of LandscapeDNDC/SIMONE. Finally, the previously envisaged observations at different inlet heights at the Beromünster tall tower and their combination with atmospheric transport simulations to derive regional scale emissions will be carried out. This work will be conducted by two PhD students at Empa and KIT.