LUCAS GATTI DOMINGUES

LUCAS GATTI DOMINGUES

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Measurement program of GHG vertical profiles at Amazon
2020 - GATTI, L.V.; MILLER, J.B.; GLOOR, M.; DOMINGUES, L.G.; CORREIA, C.S.C.; BASSO, L.; MARANI, L.; CASSOL, H.L.G.; TEJADA, G.; BORGES, V.F.; PETERS, W.; CRISPIM, S.P.; LOPES, R.; RIBEIRO, M.M.; MORAIS, C.S.; AQUINO, C.A.B.
Understanding the temporal dynamics of carbon emission from fires in the Amazon-Cerrado transition zone
2019 - CASSOL, HENRIQUE L.G.; DOMINGUES, LUCAS G.; BASSO, LUANA S.; GATTI, LUCIANA V.; MARANI, LUCIANO; TEJADA, GRACIELA; ARAI, EGIDIO; MILLER, JOHN B.; ANDERSON, LIANA O.; ARAGAO, LUIZ E.O.C.
Carbon emissions from fires (C fire) account for one-tenth of the global annual C emissions. Fires are the main source of emissions from land-use change. Recently, Werf et al. 2017, showed an 11% increase in global fire emissions during the 1997-2016 period. Savannas and Tropical Forests have shared almost the same fire-derived C emission values in the South America (Werf et al. 2017). Therefore, for this study we focused our analysis on a site representing the transition zone between Amazonia and Cerrado, located in Alta Floresta (ALF) in Mato Grosso State, Brazil. To understand the temporal dynamics of fire-derived C emission, we correlated fire counts (FC) within the influence area with fire-derived C emission directly measured in the atmosphere as CO concentration. CO and CO2 were collected monthly for 7 years from 2010 onwards using an aircraft flying up to 4.5 km altitude, totaling 153 vertical profiles. FC was extracted from influence areas weighted by the density of backward trajectories calculated quarterly. Trajectories starting from the flight location within a cell of one degree resolution were obtained using the Hysplit model at different heights. The average annual C emission from fire was 0.10 ± 0.04 Pg.C.yr-1, which represents about 10% of the Amazon fire emissions (Aragão et al. 2018). The highest daily value of fire emission was observed in 2010 (drought year) and 2017 (0.47-0.51 gC.m².day-1), although the years of 2011, 2016, and 2017 were the largest contributor to the total emission flux. This occurred because the influence area that belongs to the Amazon was lower in those years. Inter annually there is a typical behavior of the backward trajectories in ALF site whose 1st and 4th quarters have 80% of the air-streams coming from the Amazon, while during the 2nd and 3rd quarters this contribution is about 45%. However, emissions from fire and FC are higher in the 3rd quarter, outside the Amazon. The correlation between FC and fire emission was positively significant (ρ = 0.88, α = 0.05, p<0.001), meaning that an increase of 1,000 FC per quarter causes an increase of 0.074 gC.m².day-1 or, on average, an emission of 0.16 Pg.C.yr-1.
Understanding the relationships between local deforestation and CO2 atmospheric measurements in the Brazilian Amazon
2019 - TEJADA, GRACIELA; GATTI, LUCIANA; BASSO, LUANA; CASSOL, HENRIQUE L.G.; MARANI, LUCIANO; CORREIA, CAIO; DOMINGUES, LUCAS; CRISPIM, STEPHANE; NEVES, RAIANE; ANDERSON, LIANA O.; ARAGAO, LUIZ E.O.C.; ARAI, EGIDIO; GLOOR, MANUEL; MILLER, JOHN B.; VON RANDOW, CELSO
Amazon forests play a fundamental role in the global carbon balance as a carbon sink, but temperature elevations and frequents extreme events as droughts and floods could make the forests a source of CO2. Local atmospheric measurements of greenhouse gases are needed to better understand how forest will respond to climate change. The lower-troposphere greenhouse gas (GHG) monitoring program over Brazilian Amazon Basin, has been collecting biweekly GHGs vertical profiles in four sites since 2010. We aim to understand the relationships between local deforestation and CO2 aircraft measurements in the Brazilian Amazon. We calculated annual deforestation (using the Amazon Deforestation Calculation Program - PRODES), land use and cover change data (using the Brazilian Institute of Geography and Statistics - IBGE) and fire data (using the Fire Monitoring System) in each annual influence area at the four flight measurement sites of the Brazilian Amazon from 2010-2017 (and also in the mean influence area of all years by sites). We found that when we see total deforestation, it has a relationship with global CO2 emissions in the Brazilian Amazon biome. Fire has a strong relationship in the drought years, mostly in 2012. Looking at each site, we found specific correlations with deforestation, fire and land use. The biggest challenge was to compare spatial analyzes of land use change and fire with punctual data of airplane GHGs measurements. This study will contribute in our understanding of anthropogenic activities over the Amazon forest in a changing climate.
Métodos de estimativas de fluxo de gases de efeito estufa e a influência da ação humana na redução da capacidade de remoção de CO2 na Floresta Amazônica
2020 - MARANI, LUCIANO; GATTI, LUCIANA V.; MILLER, JOHN B.; DOMINGUES, LUCAS G.; CORREIA, CAIO C.S.; GLOOR, MANUEL; PETERS, WOUTER; BASSO, LUANA S.; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.
A Floresta Amazônica desempenha um papel importante para o clima tropical da América do Sul, em particular para a recirculação do vapor d’água para a atmosfera e representa um potencial reservatório de carbono que se fosse liberado totalmente contribuiria significativamente com o aquecimento global. Toda a região está sob forte pressão humana, através de exploração madeireira, conversão de floresta e outras formas de exploração de recursos. Este trabalho apresenta uma forma de examinar os fluxos de carbono na Amazônia, ao realizar perfis verticais atmosféricos de CO2 com aeronaves de pequeno porte regularmente e que sejam representativos de escalas regionais. Ao combinar estas medidas com os registros de background nas ilhas de Barbados e de Ascenção, o fluxo médio mensal de carbono para cerca de 20 % da Amazônia Brasileira pode ser estimado. Existem dois desafios primários nas medidas de CO2: precisão e acurácia. O método desenvolvido para garantir tanto a precisão quanto a acurácia dessas medidas também é apresentado. A análise das linhas de tendência entre as medidas no topo de perfil e das medidas realizadas abaixo da Camada Limite Planetária mostra uma mudança de contribuição ao longo do período estudado, que é confirmada quando se analisam os fluxos médios anuais de CO2. A tendência de mudança nos fluxos mostra comportamentos similares aos observados na mudança do uso da terra, principalmente na conversão de áreas de floresta em áreas de agropecuária, destacando a influência da ação humana na mudança da Amazônia Oriental de um sumidouro para um emissor de CO2 atmosférico.
Modelling the radiative effects of smoke aerosols on carbon fluxes in Amazon
2017 - 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 550 nm 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 22 % of the gross primary productivity of Amazonia, 9 % of plant respiration and a decline in soil respiration from of 3 %. Consequently, Amazonia net ecosystem exchange during September 2010 dropped from +101 to −104 TgC 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 50 % – 50 % 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.