Czech Hydrometeorological Institute, Prague, Czech Republic; Charles University in Prague, Faculty of Science, Institute for Environmental Studies, Czech Republic.
Czech Hydrometeorological Institute, Prague, Czech Republic.
Environ Pollut. 2016 Jun;213:1028-1041. doi: 10.1016/j.envpol.2016.01.061. Epub 2016 Feb 15.
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.
大气沉积通量的量化对于评估其对生态系统的影响至关重要。我们提出了一种先进的方法，用于估算捷克森林大气氮沉积通量的空间格局，整合了所有可用的测量数据和模型结果。本研究的目的是提供对一个国家的氮沉积通量空间格局的改进、更完整、更可靠和更现实的估计。到目前为止，这通常是基于测量环境中 NOx 浓度作为干沉积代理，以及降水[Formula: see text]和[Formula: see text]作为湿沉积代理。为了估计对干沉积有贡献的未测量物种，我们使用了 CAMx 欧拉光化学扩散模型，该模型与 Aladin 区域数值天气预报模型耦合。雾和溶解有机氮的贡献是通过一个地质统计学数据驱动模型来估计的。我们为特定的成分准备了个别地图，应用最相关的方法，然后合并所有图层，以获得代表捷克共和国氮沉积最佳估计的最终地图。考虑到未测量的物种的最终地图清楚地表明，到目前为止使用的方法可能导致氮沉积通量的大量低估。我们的结果表明，2008 年捷克森林地区的氮沉积量远远高于 2 g N m(-2) yr(-1)，近 70%的森林地区接收 3-4 g N m(-2) yr(-1)。占主导地位的干氮沉积是 NH3 和气态 HNO3，约占 80%。通过模型值估计未测量的氮物种，可以对总氮沉积进行现实的近似，也可以产生更现实的空间模式，这些模式可以作为进一步研究氮对生态系统可能影响的输入。
