Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region

Modeling the radiative effects of biomass burning aerosols on carbon fluxes in the Amazon region

Author Moreira, Demerval S. Google Scholar
Longo, Karla M. Google Scholar
Freitas, Saulo R. Google Scholar
Yamasoe, Marcia A. Google Scholar
Mercado, Lina M. Google Scholar
Rosario, Nilton E. Autor UNIFESP Google Scholar
Gloor, Emauel Google Scholar
Viana, Rosane S. M. Google Scholar
Miller, John B. Google Scholar
Gatti, Luciana V. Google Scholar
Wiedemann, Kenia T. Google Scholar
Domingues, Lucas K. G. Google Scholar
Correia, Caio C. S. Google Scholar
Abstract Every year, a dense smoke haze covers a large portion of South America originating from fires in the Amazon Basin and central parts of Brazil during the dry biomass burning season between August and October. Over a large portion of South America, the average aerosol optical depth at 550 nm exceeds 1.0 during the fire season, while the background value during the rainy season is below 0.2. Biomass burning aerosol particles increase scattering and absorption of the incident solar radiation. The regional-scale aerosol layer reduces the amount of solar energy reaching the surface, cools the near-surface air, and increases the diffuse radiation fraction over a large disturbed area of the Amazon rainforest. These factors affect the energy and CO2 fluxes at the surface. In this work, we applied a fully integrated at-mospheric model to assess the impact of biomass burning aerosols in CO2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of global solar radiation and the enhancement of the diffuse solar radiation flux inside the vegetation canopy. Our results indicate that biomass burning aerosols led to increases of about 27% in the gross primary productivity of Amazonia and 10% in plant respiration as well as a decline in soil respiration of 3%. Consequently, in our model Amazonia became a net carbon sink

net ecosystem exchange during September 2010 dropped from +101 to -104 TgC when the aerosol effects are considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results point to a dominance of the diffuse radiation effect on CO2 fluxes, reaching a balance of 50-50% between the diffuse and direct aerosol effects for high aerosol loads. For C3 grasses and savanna (cerrado), as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase in aerosol load. Taking all biomes together, our model shows the Amazon during the dry season, in the presence of high biomass burning aerosol loads, changing from being a source to being a sink of CO2 to the atmosphere.
xmlui.dri2xhtml.METS-1.0.item-coverage Gottingen
Language English
Date 2017
Published in Atmospheric Chemistry And Physics. Gottingen, v. 17, n. 23, p. 14785-14810, 2017.
ISSN 1680-7316 (Sherpa/Romeo, impact factor)
Publisher Copernicus Gesellschaft Mbh
Extent 14785-14810
Origin http://dx.doi.org/10.5194/acp-17-14785-2017
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000417753400003
URI https://repositorio.unifesp.br/handle/11600/53999

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