Determination of methane emission of the amazon basin

No panorama atual de mudanças climáticas, o Metano (CH4) é considerado o segundo principal gás de efeito estufa antrópico. Este trabalho teve como objetivo estudar o papel da Amazônia na emissão global de CH4, sendo esta a maior floresta tropical do mundo. Neste estudo foram realizados perfis verticais, utilizando aviões de pequeno porte, desde 150 m da superfície até 4,4 km, em quatro localidades da Bacia Amazônica, formando um grande quadrante abrangendo toda a Bacia. Os locais foram: próximo a Santarém (SAN; 2,8°S, 54,9°O), Alta Floresta (ALF; 8,8°S, 56,7°O), Rio Branco (RBA; 9,3°S, 67,6°O) e Tabatinga (TAB; 5,9°S, 70,0°O). Foram realizados quatro anos (2010-2013) de medidas contínuas em escala regional, quinzenalmente, totalizando 293 perfis verticais. Até o presente momento estas medidas são únicas e representam uma nova abordagem nas emissões nesta escala. Foram calculados os fluxos de CH4 nestas quatro localidades por meio do Método de Integração de Coluna e os fluxos anuais foram calculados através de média proporcional, considerando a área de influência de cada localidade. Os anos de 2010 e 2012 foram anos de seca, enquanto 2011 e 2013 foram anos com precipitação acima da média na Amazônia. Dos quatro anos de estudo apenas 2011 apresentou uma temperatura inferior a média. Os resultados obtidos mostraram que a Amazônia atua como uma importante fonte de CH4, com uma emissão de 25,4 Tg ano-1 (4% - 5% da emissão global), considerando a área da Amazônia Brasileira (4,2 milhões de km2). As emissões nesta região apresentaram variações regionais e anuais, com maiores emissões nos anos de seca. A emissão pela queima de biomassa não foi significativa nas regiões de estudo, enquanto as estimativas de emissões por fermentação entérica e manejo dos dejetos de animais foram significativas na maioria destas regiões. Os resultados obtidos ressaltam a importância da realização de estudos em escala regional para esclarecer o comportamento de toda a área da Bacia Amazônica Brasileira.In the current scenario of climate change, Methane (CH4) is the second main anthropogenic greenhouse gas. This work aimed to study the role of Amazon in the global CH4 emission, which is the largest rainforest in the world. In this study vertical profiles were performed using small aircraft, from 150 m from the surface to 4.4 km in four sites in the Amazon Basin, forming a large quadrant covering the entire basin. The sites were: near Santarem (SAN, 2.8°S, 54.9°W), Alta Floresta (ALF, 8.8°S, 56.7°W), Rio Branco (RBA, 9.3°S, 67.6°W) and Tabatinga (TAB, 5.9°S, 70.0°W). Were made four years (2010-2013) of continuous measures on a regional scale, every two weeks, with a total of 293 vertical profiles. Until now these measures are unique and represent a new approach in emissions on this scale. The CH4 fluxes were calculated in these four locations through the Column Integration Technique and annual fluxes were calculated using proportional average, considering the area of influence of each location. The years 2010 and 2012 were years of drought, while 2011 and 2013 were years with total precipitation higher than the average in the Amazon. In these four years of study only in 2011 showed a lower average temperature. The results showed that the Amazon was a source of CH4, with an annual emission of 25.4 Tg (4% - 5% of global emission), considering the Brazilian Amazon area (4,2 millions km2). Emissions in this region presented regional and annual variations, with more emissions during drought years. Emissions from biomass burning was not significant, while emissions from enteric fermentation was significant in the study areas. The results obtained highlight the importance of make studies with regional scale and long temporal series to clarify the behavior of the entire Brazilian Amazon area

Study of amazon basin methane emissions using airplane vertical profiles

O Metano (CH4) é o segundo gás de efeito estufa mais importante, com aproximadamente 40% de sua emissão proveniente de fontes naturais, enquanto as fontes antrópicas representam cerca de 60%. Sua média global em 2009 foi de 1803ppb, que representa um aumento de 5ppb em relação ao ano anterior. Neste estudo foram calculados os fluxos de CH4, utilizando medidas de perfis verticais com aviões de pequeno porte, desde a superfície até 4,4km na Bacia Amazônica, sobre Santarém (SAN), Alta Floresta (ALF), Rio Branco (RBA) e Tabatinga (TAB), por meio do Método de Integração de Coluna. Estas medidas de CH4 em escala regional até o presente momento são únicas e representam uma nova abordagem nas emissões nesta escala. As medidas em SAN foram realizadas entre 2000 e 2010 e o fluxo de CH4 encontrado para este período foi de 53,0 ± 27,9mgCH4.m-2.dia-1. Para o ano de 2010, o maior fluxo de emissão de CH4 foi observado no lado leste da Bacia Amazônica, entre a costa e SAN, 56,4 ± 22,4mgCH4.m-2.dia-1. Entre a costa e ALF, ao sul da Bacia Amazônica, o fluxo médio anual foi de 17,1 ± 2,3mgCH4.m-2.dia-1, e entre a costa e os locais TAB e RBA, no lado oeste da Bacia, foi observado um fluxo médio anual de 18,7 ± 4,2 e 19,3 ± 10,2mgCH4.m-2.dia-1, respectivamente. Extrapolando os resultados obtidos em TAB e RBA para toda a área da Bacia Amazônica (5 milhões Km2) obtêm-se uma emissão de 34,7 ± 13,5TgCH4.ano-1. Com o objetivo de determinar a influência da queima de biomassa no fluxo regional de emissão de CH4, foi utilizada a correlação 6,4ppbCO/ppbCH4 calculada neste estudo, ALF foi o local de estudo que apresentou a maior influência no fluxo de CH4 oriundo da queima de biomassa, 23% do fluxo total anual.Methane (CH4) is the second most important greenhouse gas with approximately 40% of emission from natural sources, while anthropogenic sources account for about 60%. The global average was 1803ppb in 2009, representing an increase of 5ppb in relation to the previous year. This study calculated the fluxes of CH4, using measurements of vertical profiles with small aircraft, from the surface to 4.4km in the Amazon Basin, over Santarém (SAN), Alta Floresta (ALF), Rio Branco (RBA) and Tabatinga (TAB), using the Column Integration Technique. These measurements of CH4 at a regional scale until now are unique and represent a new approach to emissions on this scale. SAN measurements were realized between 2000 and 2010 and CH4 flux found for this period was 53.0 ± 27.9mgCH4.m-2.day-1. For the year 2010, the largest flux of CH4 emission was observed in the eastern Amazon Basin, between the coast and SAN, 56.4 ± 22.4mgCH4.m-2.day-1. Between the coast and ALF, located in the south of the Amazon Basin, the annual mean flux was 17.1 ± 2.3mgCH4.m -2.day-1, and between the coast and the local TAB and RBA on the west side of the Basin was observed an mean annual flux of 18.7 ± 4.2 and 19.3 ± 10.2mgCH4.m-2.day-1, respectively. Extrapolating the results obtained in TAB and RBA for the whole area of the Amazon Basin (5 million km2) to obtain an emission of 34,7 ± 13,5TgCH4.year-1. In order to determine the influence of biomass burning on regional emission flux of CH4, was used a correlation 6.4ppbCO/ppbCH4 calculated in this study, ALF was the site that had the most influence on the CH4 flux from the burning biomass, 23% of the total annual flux

Posterior Amazon monthly mean surface carbon flux between 2010 and 2018 estimated using the INVICAT 4D-Var inverse model

This data set consist of a single netcdf file with a set of optimised global surface carbon fluxes (CO2), estimated by variational inverse methods using the TOMCAT chemical transport model, and the INVICAT inverse transport model. We assimilate in-situ surface flask observations from global surface observation sites and Amazonian lower-troposphere vertical profiles of CO2. The vertical profile data used here are available at PANGAEA Data Archiving, at https://doi.org/10.1594/PANGAEA.926834 and more details could be found at Gatti et al. (2021). These surface fluxes are monthly mean values for total emissions (labelled TOTAL_FLUX) on the (approximately) 5.6-degree horizontal model grid. The associated uncertainty for the flux from each grid cell is also included (labelled TOTAL_FLUX_ERROR). The fluxes and uncertainties cover the period of January 2010 to December 2018 and units are gC/m2/day, and time units are days since January 1st 2010. Further details about the data can be found in Basso et al. (2023) in the documentation section

CH4 Aircraft Vertical Profiles Measurements at Four Amazonian Sites Between 2010 and 2018

To improve diagnosis of Amazonia's carbon cycle, starting in 2010, we initiated regular observation of lower troposphere CH4 concentrations at four aircraft vertical profiling sites spread over the Brazilian Amazonia. The four sites from the CARBAM project at Amazonia: SAN (2.86S 54.95W); ALF (8.80S 56.75W); RBA (9.38S 67.62W); TAB (5.96S 70.06W) was from 2010 to 2012 and TEF (3.39S 65.6W), started in 2013. The sampling period was typically twice per month (Gatti et al., 2014; Basso et al., 2016; Miller et al., 2007; d'Amelio et al., 2009; Domingues et al., 2020). Over nine-years, 590 vertical profiles were performed in a descending spiral profile from 4420 m to 300 m a.s.l. A mean of 75 vertical profiles was performed per year from 2010 to 2018 at the 4 sites, except for 2015 and 2016. In 2015 the flight collection was stopped in April at all sites, returning only in November at RBA. In 2016 only RBA and ALF were measured. The vertical profiles were usually taken between 12:0 and 13:00 local time. Air is sampled by semi-automatic filling of 0.7 L boro-silicate flasks inside purpose-built suitcases (PFP -Programmable Flask Package) (Tans et al., 1996); there are two versions, one with 17 flasks at SAN, and another with 12 flasks at TAB_TEF, ALF and RBA. This suitcase is connected to a compressor package (PCP –Portable Compressor Package), containing batteries and 2 compressors, which is connected to an air inlet on the outside of the aircraft at wing or window, depending on the aircraft model. Once a PFP (i.e. one vertical profile) has been filled with air the PFP is transported (from 2010 to 2014) to the IPEN (Instituto de Pesquisas Energéticas e Nucleares) Atmospheric Chemistry Laboratory in Sao Paulo, Brazil and since 2015 to the INPE/ LaGEE(Instituto Nacional de Pesquisas Espaciais/Greenhouse Gases Laboratory), in Sao Jose dos Campos, Sao Paulo state, Brazil. This laboratory is a replica of the NOAA/ESRL/GMD trace gas analysis system at Boulder, Colorado, USA, and was constructed in 2003 and sent to IPEN where started the analysis in 2004. The CH 4 analysis system is an FID (Flame Ionization Detector) chromatography (HP6890 Plus+ model) with pre-column of 198 cm of length and 3/16” o.d. (Silica Gel 80/100 mesh), a column of 106 cm of length and 3/16” o.d. (Molecular Sieve 5A 80/100 mesh), and a 12 mL volume sample loop (see Basso et al. 2016 for a detailed description). In order to assess the accuracy and long-term repeatability of the CH4 measurements, a previously calibrated sample is measured as an unknown in the system regularly. These results indicate long-term repeatability (one sigma) of 1.0 ppb. An inter-comparison between INPE and NOAA of weekly measurements at NAT (Brazilian northeast coast site) had a mean difference of 0.24±2.67 ppb (r = 0.98)

CO2 Vertical Profiles on Four Sites over Amazon from 2010 to 2018

To improve diagnosis of Amazonia's carbon cycle, starting in 2010, we initiated regular observation of lower troposphere CO2 concentrations at four aircraft vertical profiling sites spread over the Brazilian Amazonia. The four sites from the CARBAM project at Amazonia: SAN (2.86S 54.95W); ALF (8.80S 56.75W); RBA (9.38S 67.62W); TAB (5.96S 70.06W) was from 2010 to 2012 and TEF (3.39S 65.6W), started in 2013. The sampling period was typically twice per month (Gatti et al., 2014; Basso et al., 2016; Miller et al., 2007; d'Amelio et al., 2009; Domingues et al., 2020). Over nine-years, 590 vertical profiles were performed in a descending spiral profile from 4420 m to 300 m a.s.l. A mean of 75 vertical profiles was performed per year from 2010 to 2018 at the 4 sites, except for 2015 and 2016. In 2015 the flight collection was stopped in April at all sites, returning only in November at RBA. In 2016 only RBA and ALF were measured. The vertical profiles were usually taken between 12:0 and 13:00 local time. Air is sampled by semi-automatic filling of 0.7 L boro-silicate flasks inside purpose-built suitcases (PFP -Programmable Flask Package) (Tans et al., 1996); there are two versions, one with 17flasks at SAN, and another with 12 flasks at TAB_TEF, ALF and RBA. This suitcase is connected to a compressor package (PCP –Portable Compressor Package), containing batteries and 2 compressors, which is connected to an air inlet on the outside of the aircraft at wing or window, depending on the aircraft model. Once a PFP (i.e. one vertical profile) has been filled with air the PFP is transported (from 2010 to 2014) to the IPEN (Instituto de Pesquisas Energéticas e Nucleares) Atmospheric Chemistry Laboratory in Sao Paulo, Brazil and since 2015 to the INPE/ LaGEE(Instituto Nacional de Pesquisas Espaciais/Greenhouse Gases Laboratory), in Sao Jose dos Campos, Sao Paulo state, Brazil. This laboratory is a replica of the NOAA/ESRL/GMD trace gas analysis system at Boulder, Colorado, USA, and was constructed in 2003 and sent to IPEN where started the analysis in 2004.Air samples were analysed with a non-dispersive infrared (NDIR) analyser for CO2. To ensure the accuracy, we construct a calibration curve every 2 samples. The calibration curve constructed with 3-standards concentrations, produced by NOAA/ESRL/GMD. The “High” (10 ppm higher than medium), “medium” (similar to mean CO2 concentration founded in Amazonia), and “Low” (10 ppm lower than medium). We have an intercomparison program with NOAA at Natal site (5S, 35W, located at Brazilian northeast coast) where the comparison IPEN/INPE-NOAA was -0.05 ± 0.38ppm. The precision is analysed based on CO2mole fraction from “target tanks” (calibrated CO2in air in high pressure cylinders treated as unknowns by NOAA) and demonstrated long-term repeatability of 0.03ppm and a difference between measured and calibrated values of 0.03 ppm. Additional information can be shared from the LaGEE/INPE group as temperature, precipitation, and others parameters used by the group for the Nature paper entitled “Decrease in Amazonia carbon uptake linked to trends in deforestation and climate” (Gatti et al, 2021)

Impacts on South America moisture transport under Amazon deforestation and 2 °C global warming

The increase in greenhouse gasses (GHG) anthropogenic emissions and deforestation over the last decades have led to many chemical and physical changes in the climate system, affecting the atmosphere's energy and water balance. A process that could be affected is the Amazonian moisture transport in the South American continent (including La Plata basin), which is crucial to the southeast Brazilian water regime. The focus of our research is on evaluating how local (i.e. Amazon deforestation) and global forcings (increase of atmospheric GHG concentration) may modify this moisture transport under climate change scenarios. We used two coupled land-atmosphere models forced by CMIP6 sea surface temperatures to simulate these processes for two scenarios: i) increase in carbon dioxide (CO2) — RCP8.5 atmospheric levels (00DEF), and ii) total Amazon deforestation simultaneous with atmospheric CO2 levels increased (100DEF). These scenarios were compared with a control simulation, set with a constant CO2 of 388 ppm and present-day Amazon Forest cover. The 30-year Specific Warming Level 2 (SWL2) index evaluated from the simulations is set to be reached 2 years earlier due to Amazon deforestation. A reduction in precipitation was observed in the Amazon basin (−3.1 mm·day−1) as well as in La Plata Basin (−0.5 mm·day−1) due to reductions in the Amazon evapotranspiration (−0.9 mm·day−1) through a stomatal conductance decrease (00DEF) and land cover change (100DEF). In addition, the income moisture transport decreased (22 %) in the northern La Plata basin in both scenarios and model experiments. Our results indicated a worse scenario than previously found in the region. Both Amazon and La Plata hydrological regimes are connected (moisture and energy transport), indicating that a large-scale Amazon deforestation will have additional climate, economic and social implications for South America