Sensitivity studies on the photolysis rates calculation in Amazonian atmospheric chemistry ? Part I: The impact of the direct radiative effect of biomass burning aerosol particles

L. M. M. Albuquerque (1, 2) , K. M. Longo (1) , S. R. Freitas (1) , T. Tarasova (1) , Artemio Plana-Fattori , C. Nobre (1) , L. V. Gatti (3)

1 CPTEC - Center for Weather Forecasting and Climate Studies [São Paulo]
2 UFMS - Universidade Federal de Mato Grosso do Sul
3 IPEN/CNEN-SP - Instituto de Pesquisas Energéticas e Nucleares [São Paulo]

The impact of the direct radiative effect of the aerosol particles on the calculation of the photolysis rates and consequently on the atmospheric chemistry in regional smoke clouds due to biomass burning over the Amazon basin is addressed in this work. It explores a case study for 19 September 2002 at LBA-RACCI-SMOCC (The Large-Scale Biosphere-Atmosphere experiment in Amazonia ? Radiation, Cloud, and Climate Interactions ? Smoke, Aerosols, Clouds, Rainfall and Climate) pasture site in SW Amazonia. The Tropospheric Ultraviolet Visible radiation model (TUV) version 4.2, (Madronich et al., 1987) is used for the photolysis rates calculation considering the layer aerosol optical depth from the Coupled Aerosol Tracer Transport model to the Brazilian Regional Atmospheric Modeling System (CATT-BRAMS) (Freitas et al., 2005). A dynamical aerosol model (Procópio et al., 2003) is included in the radiative transfer model to take into account the high temporal variability of the aerosol optical thickness. This methodology is tested by comparing modeled and measured clear sky solar irradiances. The results show a good agreement with measured PAR radiation values. The actinic flux attenuation, for AOT (500 nm) values around 1.94, decreases the photolysis rates by about 70% in the presence of near-ground smoke aerosol and above the smoke layer the photolysis process tends to increase by about 40%. A simulation of the ozone production is carried out using a one-dimensional photochemical box model and comparisons with observation are shown.

Domaines: Océan, Atmosphère

L. M. M. Albuquerque, K. M. Longo, S. R. Freitas, T. Tarasova, Artemio Plana-Fattori, et al.. Sensitivity studies on the photolysis rates calculation in Amazonian atmospheric chemistry ? Part I: The impact of the direct radiative effect of biomass burning aerosol particles. Atmospheric Chemistry and Physics Discussions, 2005, 5 (5), pp.9325-9353. ⟨hal-00303942⟩