LUCAS GATTI DOMINGUES
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Artigo IPEN-doc 23086 Modelling the radiative effects of smoke aerosols on carbon fluxes in Amazon2017 - MOREIRA, DEMERVAL S.; LONGO, KARLA M.; FREITAS, SAULO R.; YAMASOE, MARCIA A.; MERCADO, LINA M.; ROSARIO, NILTON E.; GLOOR, EMANUEL; VIANA, ROSANE S.M.; MILLER, JOHN B.; GATTI, LUCIANA V.; WIEDEMANN, KENIA T.; DOMINGUES, LUCAS K.G.; CORREIA, CAIO C.S.Every year, a dense smoke haze of regional dimensions covers a large portion of South America originated from fire activities 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 550ānm exceeds 1.0 during the fire season while the background value during the rainy season is below 0.2. Smoke 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 atmospheric model to assess the impact of smoke aerosols in CO2 fluxes in the Amazon region during 2010. We address the effects of the attenuation of the solar global radiation and the enhancement of the diffuse solar radiation flux inside the canopy. Our results indicated that the smoke aerosols led to an increase of about 22ā% of the gross primary productivity of Amazonia, 9ā% of plant respiration and a decline in soil respiration from of 3ā%. Consequently, Amazonia net ecosystem exchange during September 2010 dropped from +101 to ā104āTgC when the aerosol effects were considered, mainly due to the aerosol diffuse radiation effect. For the forest biome, our results pointed to a dominance of the diffuse radiation effect on CO2 fluxes, reaching a balance of 50ā% ā 50ā% between the diffuse and direct aerosol effects for high aerosol loads. For C3 grass type and cerrado, as expected, the contribution of the diffuse radiation effect is much lower, tending to zero with the increase of aerosol load. That is, the Amazon during the dry season, in the presence of high smoke aerosol loads, change from being a source to be a sink of CO2 to the atmosphere.Artigo IPEN-doc 22700 Consistent regional fluxes of CHsub(4) and COsub(2) inferred from GOSAT proxy XCHsub(4)XCOsub(2) retrievals, 2010-20142017 - FENG, LIANG; PALMER, PAUL I.; BĆSCH, HARTMUT; PARKER, ROBERT J.; WEBB, ALEX J.; CORREIA, CAIO S.C.; DEUTSCHER, NICHOLAS M.; DOMINGUES, LUCAS G.; FEIST, DIETRICH G.; GATTI, LUCIANA V.; GLOOR, EMANUEL; HASE, FRANK; KIVI, RIGEL; LIU, YI; MILLER, JOHN B.; MORINO, ISAMU; SUSSMANN, RALF; STRONG, KIMBERLY; UCHINO, OSAMU; WANG, JING; ZAHN, ANDREASWe use the GEOS-Chem global 3-D model of atmospheric chemistry and transport and an ensemble Kalman filter to simultaneously infer regional fluxes of methane (CH4) and carbon dioxide (CO2) directly from GOSAT retrievals of XCH4:XCO2, using sparse ground-based CH4 and CO2 mole fraction data to anchor the ratio. This work builds on previously reported theory that takes advantage that: 1) these ratios are less prone to systematic error than either the full physics data products or the proxy CH4 data products; and 2) the resulting CH4 and CO2 fluxes are self-consistent. We show that a posteriori fluxes inferred from the GOSAT data generally outperform the fluxes inferred only from in situ data, as expected. GOSAT CH4 and CO2 fluxes are consistent with global growth rates for CO2 and CH4 reported by NOAA, and with a range of independent data including in particular new profile measurements (0-7 km) over the Amazon basin that were collected specifically to help validate GOSAT over this geographical region. We find that large-scale multi-year annual a posteriori CO2 fluxes inferred from GOSAT data are similar to those inferred from the in situ surface data but with smaller uncertainties, particularly over the tropics. GOSAT data are consistent with smaller peak-topeak seasonal amplitudes of CO2 than either a priori or the in situ inversion, particularly over the tropics and the southern extra-tropics. Over the northern extra-tropics, GOSAT data show larger uptake than the a priori but less than the in situ inversion, resulting in small net emissions over the year. We also find evidence that the carbon balance of tropical South America was perturbed following the droughts of 2010 and 2012 with net annual fluxes not returning to an approximate annual balance until 2013. In contrast, GOSAT data significantly changed the a priori spatial distribution of CH4 emission with a 40% increase over tropical South America and tropical Asia and smaller decrease over Eurasia and temperate South America. We find no evidence from GOSAT that tropical South American CH4 fluxes were dramatically affected by the two large-scale Amazon droughts. However, we find that GOSAT data are consistent with double seasonal peaks in fluxes that are reproduced over the five years we studied: a small peak in January to April and a larger peak 60 in June to October, which is likely due to superimposed emissions from different geographical regions.