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@ARTICLE{Luo:21189,
      author       = {Luo, G.J. and Brüggemann, N. and Wolf, B. and Gasche, R.
                      and Grote, R. and Butterbach-Bahl, K.},
      title        = {{D}ecadal variability of soil {CO}2, {NO}, {N}2{O}, and
                      {CH}4 fluxes at the {H}öglwald {F}orest, {G}ermany},
      journal      = {Biogeosciences},
      volume       = {9},
      issn         = {1726-4170},
      address      = {Katlenburg-Lindau [u.a.]},
      publisher    = {Copernicus},
      reportid     = {PreJuSER-21189},
      pages        = {1741 - 1763},
      year         = {2012},
      note         = {The authors are grateful to Georg Willibald and colleagues
                      for supporting field measurements at the Hoglwald Forest
                      site and Matthias Mauder for plausibility tests on
                      EddyCovariance data. This research was supported by the
                      Helmholtz Association of German Research Centers in the
                      framework of the program-oriented funding (POF) and by the
                      FP6 Integrated Project NitroEurope IP, funded by the
                      European Commission.},
      abstract     = {Besides agricultural soils, temperate forest soils have
                      been identified as significant sources of or sinks for
                      important atmospheric trace gases (N2O, NO, CH4, and CO2).
                      Although the number of studies for this ecosystem type
                      increased more than tenfold during the last decade, studies
                      covering an entire year and spanning more than 1-2 years
                      remained scarce. This study reports the results of
                      continuous measurements of soil-atmosphere C-and N-gas
                      exchange with high temporal resolution carried out since
                      1994 at the Hoglwald Forest spruce site, an experimental
                      field station in Southern Germany. Annual soil N2O, NO and
                      CO2 emissions and CH4 uptake (1994-2010) varied in a range
                      of 0.2-3.0 kgN(2)O-N ha(-1) yr(-1), 6.4-11.4 kg NO-N ha(-1)
                      yr(-1), 7.0-9.2 t CO2-C ha(-1) yr(-1), and 0.9-3.5 kgCH(4)-C
                      ha(-1) yr(-1), respectively. The observed high fluxes of
                      N-trace gases are most likely a consequence of high rates of
                      atmospheric nitrogen deposition (>20 kg N ha(-1) yr(-1)) of
                      NH3 and NOx to our site. For N2O, cumulative annual
                      emissions were >= 0.8 kg N2O-N ha(-1) yr(-1) in years with
                      freeze-thaw events (5 out 14 of years). This shows that
                      long-term, multi-year measurements are needed to obtain
                      reliable estimates of N2O fluxes for a given ecosystem.
                      Cumulative values of soil respiratory CO2 fluxes tended to
                      be highest in years with prolonged freezing periods, i.e.
                      years with below average annual mean soil temperatures and
                      high N2O emissions (e.g. the years 1996 and
                      2006).Furthermore, based on our unique database on trace gas
                      fluxes we analyzed if soil temperature, soil moisture
                      measurements can be used to approximate trace gas fluxes at
                      daily, weekly, monthly, or annual scale. Our analysis shows
                      that simple-to-measure environmental drivers such as soil
                      temperature or soil moisture are suitable to approximate
                      fluxes of NO and CO2 at weekly and monthly resolution
                      reasonably well (accounting for up to $59\%$ of the
                      variance). However, for CH4 we so far failed to find
                      meaningful correlations, and also for N2O the predictive
                      power is rather low. This is most likely due to the
                      complexity of involved processes and counteracting effects
                      of soil moisture and temperature, specifically with regard
                      to N2O production and consumption by denitrification and
                      microbial community dynamics. At monthly scale, including
                      information on gross primary production (CO2, NO), and N
                      deposition (N2O), increased significantly the explanatory
                      power of the obtained empirical regressions (CO2: r(2) =
                      0.8; NO: r(2) = 0.67; N2O, all data: r(2) = 0.5; N2O, with
                      exclusion of freeze-thaw periods: r(2) = 0.65).},
      keywords     = {J (WoSType)},
      cin          = {IBG-3},
      ddc          = {570},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {Terrestrische Umwelt},
      pid          = {G:(DE-Juel1)FUEK407},
      shelfmark    = {Ecology / Geosciences, Multidisciplinary},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000305829800001},
      doi          = {10.5194/bg-9-1741-2012},
      url          = {https://juser.fz-juelich.de/record/21189},
}