Dry and wet deposition of inorganic nitrogen compounds to a tropical pasture site (Rondônia, Brazil)
Item
Title (Dublin Core)
Dry and wet deposition of inorganic nitrogen compounds to a tropical pasture site (Rondônia, Brazil)
Description (Dublin Core)
The input of nitrogen (N) to ecosystems has increased dramatically over the past decades. While total (wet + dry) N deposition has been extensively determined in temperate regions, only very few data sets of N wet deposition exist for tropical ecosystems, and moreover, reliable experimental information about N dry deposition in tropical environments is lacking. In this study we estimate dry and wet deposition of inorganic N for a remote pasture site in the Amazon Basin based on in-situ measurements. The measurements covered the late dry (biomass burning) season, a transition period and the onset of the wet season (clean conditions) (12 September to 14 November 2002) and were a part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign. Ammonia (NH<sub>3</sub>), nitric acid (HNO<sub>3</sub>), nitrous acid (HONO), nitrogen dioxide (NO<sub>2</sub>), nitric oxide (NO), ozone (O<sub>3</sub>), aerosol ammonium (NH<sub>4</sub><sup>+</sup>) and aerosol nitrate (NO<sub>3</sub><sup>-</sup>) were measured in real-time, accompanied by simultaneous meteorological measurements. Dry deposition fluxes of NO<sub>2</sub> and HNO<sub>3</sub> are inferred using the 'big leaf multiple resistance approach' and particle deposition fluxes are derived using an established empirical parameterization. Bi-directional surface-atmosphere exchange fluxes of NH<sub>3</sub> and HONO are estimated by applying a 'canopy compensation point model'. N dry and wet deposition is dominated by NH<sub>3</sub> and NH<sub>4</sub><sup>+</sup>, which is largely the consequence of biomass burning during the dry season. The grass surface appeared to have a strong potential for daytime NH<sub>3</sub> emission, owing to high canopy compensation points, which are related to high surface temperatures and to direct NH<sub>3</sub> emissions from cattle excreta. NO<sub>2</sub> also significantly accounted for N dry deposition, whereas HNO<sub>3</sub>, HONO and N-containing aerosol species were only minor contributors. Ignoring NH<sub>3</sub> emission from the vegetation surface, the annual net N deposition rate is estimated to be about −11 kgN ha<sup>-1</sup> yr<sup>-1</sup>. If on the other hand, surface-atmosphere exchange of NH<sub>3</sub> is considered to be bi-directional, the annual net N budget at the pasture site is estimated to range from −2.15 to −4.25 kgN ha<sup>-1</sup> yr<sup>-1</sup>.
Creator (Dublin Core)
Trebs, I.
Lara, L. L.
Zeri, L. M. M.
Gatti, L. V.
Artaxo, P.
Dlugi, R.
Slanina, J.
Andreae, M. O.
Meixner, F. X.
Date (Dublin Core)
2018-06-28
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-6-447-2006
https://acp.copernicus.org/articles/6/447/2006/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
