Ozone production and transport over the Amazon Basin during the dry-to-wet and wet-to-dry transition seasons
Item
Title (Dublin Core)
Ozone production and transport over the Amazon Basin during the dry-to-wet and wet-to-dry transition seasons
Description (Dublin Core)
The Regional Carbon Balance in Amazonia (BARCA) campaign provided the first Amazon Basin-wide aircraft measurements of ozone (O<sub>3</sub>) during both the dry-to-wet (November and December 2008) and wet-to-dry (May 2009) transition seasons. Extremely low background values (< 20 ppb) were observed to the west and north of Manaus in both seasons and in all regions during the wet-to-dry transition. On the other hand, elevated O<sub>3</sub> levels (40–60 ppb) were seen during the dry-to-wet transition to the east and south of Manaus, where biomass burning emissions of O<sub>3</sub> precursors were present. Chemistry simulations with the CCATT-BRAMS and WRF-Chem models are within the error bars of the observed O<sub>3</sub> profiles in the boundary layer (0–3 km a.s.l.) in polluted conditions. However, the models overestimate O<sub>3</sub> in the boundary layer in clean conditions, despite lacking the predominant NO source from soil. In addition, O<sub>3</sub> simulated by the models was either within the error bars or lower than BARCA observations in mid-levels (3–5 km a.s.l.), and lower than total tropospheric O<sub>3</sub> retrieved from the OMI/MLS instruments, which is primarily comprised of middle troposphere O<sub>3</sub> and thus reflects long-range transport processes. Therefore, the models do a relatively poor job of representing the free troposphere-boundary layer gradient in O<sub>3</sub> compared with aircraft and satellite observations, which could be due to missing long-range and convective transport of O<sub>3</sub> at mid-levels. Additional simulations with WRF-Chem showed that the model O<sub>3</sub> production is very sensitive to both the O<sub>3</sub> deposition velocities and the NO<sub>x</sub> emissions, which were both about one-half of observed values. These results indicate the necessity of more realistic model representations of emissions, deposition, and convective processes for accurate monitoring and prediction of increases in O<sub>3</sub> production in the Amazon Basin as the regional population grows.
Creator (Dublin Core)
Bela, M. M.
Longo, K. M.
Freitas, S. R.
Moreira, D. S.
Beck, V.
Wofsy, S. C.
Gerbig, C.
Wiedemann, K.
Andreae, M. O.
Artaxo, P.
Date (Dublin Core)
2018-09-17
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-15-757-2015
https://acp.copernicus.org/articles/15/757/2015/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
