title: Towards a better spatial quantification of nitrogen deposition: A case study for Czech forests.
abstract: The quantification of atmospheric deposition flux is essential for assessment of its impact on ecosystems. We present an advanced approach for the estimation of the spatial pattern of atmospheric nitrogen deposition flux over the Czech forests, collating all available measured data and model results. The aim of the presented study is to provide an improved, more complete, more reliable and more realistic estimate of the spatial pattern of nitrogen deposition flux over one country. This has so far usually been based on measurements of ambient NOx concentrations as dry deposition proxy, and [Formula: see text] and [Formula: see text] in precipitation as wet deposition proxy. For estimation of unmeasured species contributing to dry deposition, we used the CAMx Eulerian photochemical dispersion model, coupled with the Aladin regional numeric weather prediction model. The contribution of fog and dissolved organic nitrogen was estimated using a geostatistical data driven model. We prepared individual maps for particular components applying the most relevant approach and then merged all layers to obtain a final map representing the best estimate of nitrogen deposition over the Czech Republic. Final maps accounting for unmeasured species clearly indicate that the approach used so far may result in a substantial underestimation of nitrogen deposition flux. Our results showed that nitrogen deposition over the Czech forested area in 2008 was well above 2 g N m(-2) yr(-1), with almost 70% of forested area receiving 3-4 g N m(-2) yr(-1). NH3 and gaseous HNO3, contributing about 80%, dominated the dry nitrogen deposition. Estimating the unmeasured nitrogen species by modeled values provides realistic approximations of total nitrogen deposition that also result in more realistic spatial patterns that could be used as input for further studies of likely nitrogen impacts on ecosystems.
authors.affiliation: Czech Hydrometeorological Institute, Prague, Czech Republic; Charles University in Prague, Faculty of Science, Institute for Environmental Studies, Czech Republic. Electronic address: hunova@chmi.cz.
authors.forename: Iva
authors.initials: I
authors.lastname: Hůnová
authors.affiliation: Czech Hydrometeorological Institute, Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Kurfürst
authors.affiliation: Czech Hydrometeorological Institute, Prague, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Vlček
authors.affiliation: Czech Hydrometeorological Institute, Prague, Czech Republic; Charles University in Prague, Faculty of Science, Institute for Environmental Studies, Czech Republic.
authors.forename: Vojtěch
authors.initials: V
authors.lastname: Stráník
authors.affiliation: Czech Hydrometeorological Institute, Prague, Czech Republic; Charles University in Prague, Faculty of Science, Institute for Environmental Studies, Czech Republic.
authors.forename: Petra
authors.initials: P
authors.lastname: Stoklasová
authors.affiliation: Czech Hydrometeorological Institute, Prague, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Schovánková
authors.affiliation: Czech Hydrometeorological Institute, Prague, Czech Republic.
authors.forename: Daša
authors.initials: D
authors.lastname: Srbová
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere / Q000737:chemistry*; D018153:Czech Republic; D004784:Environmental Monitoring / Q000379:methods*; D065928:Forests; D015233:Models, Statistical; D009584:Nitrogen / Q000032:analysis*; D014197:Trees; D014867:Water; D014887:Weather
chemical_list: D000393:Air Pollutants; D014867:Water; D009584:Nitrogen
keywords: Atmospheric deposition; Forests; Nitrogen; Spatial pattern