Papers by Caio S C Correia
Despite the consensus on the overall downward trend in Amazon forest loss in the previous decade,... more Despite the consensus on the overall downward trend in Amazon forest loss in the previous decade, estimates of yearly carbon emissions from deforestation still vary widely. Estimated carbon emissions are currently often based on data from local logging activity reports, changes in remotely sensed biomass, and remote detection of fire hotspots and burned area. Here, we use 16 years of satellite-derived carbon monoxide (CO) columns to constrain fire CO emissions from the Amazon Basin between 2003 and 2018. Through data assimilation, we produce 3 d average maps of fire CO emissions over the Amazon, which we verified to be consistent with a long-term monitoring programme of aircraft CO profiles over five sites in the Amazon. Our new product independently confirms a long-term decrease of 54 % in deforestation-related CO emissions over the study period. Interannual variability is large, with known anomalously dry years showing a more than 4-fold increase in basin-wide fire emissions relative to wet years. At the level of individual Brazilian states, we find that both soil moisture anomalies and human ignitions determine fire activity, suggesting that future carbon release from fires depends on drought intensity as much as on continued forest protection. Our study shows that the atmospheric composition perspective on deforestation is a valuable additional monitoring instrument that complements existing bottom-up and remote sensing methods for land-use change. Extension of such a perspective to an operational framework is timely considering the observed increased fire intensity in the Amazon Basin between 2019 and 2021.
Communications Earth & Environment
Atmospheric methane concentrations were nearly constant between 1999 and 2006, but have been risi... more Atmospheric methane concentrations were nearly constant between 1999 and 2006, but have been rising since by an average of ~8 ppb per year. Increases in wetland emissions, the largest natural global methane source, may be partly responsible for this rise. The scarcity of in situ atmospheric methane observations in tropical regions may be one source of large disparities between top-down and bottom-up estimates. Here we present 590 lower-troposphere vertical profiles of methane concentration from four sites across Amazonia between 2010 and 2018. We find that Amazonia emits 46.2 ± 10.3 Tg of methane per year (~8% of global emissions) with no temporal trend. Based on carbon monoxide, 17% of the sources are from biomass burning with the remainder (83%) attributable mainly to wetlands. Northwest-central Amazon emissions are nearly aseasonal, consistent with weak precipitation seasonality, while southern emissions are strongly seasonal linked to soil water seasonality. We also find a disti...
submitted for GGMT-2017 Long Term Nitrous Oxide Measurements Over Amazon Basin Using Small Aircra... more submitted for GGMT-2017 Long Term Nitrous Oxide Measurements Over Amazon Basin Using Small Aircraft C. S. C. Correia; L. V. Gatti; L. G. Domingues; R. S. Santos; W. R. Costa, S. P. Crispim, V. F. Borges; L. Marani, E. U. Gloor; J. B. Miller. 1 Nuclear and Energy Research Institute, IPEN-CNEN/SP, Brazil; [email protected] 2 National Institute for Spaces Research, INPE/CCST, São José dos Campos-SP, Brazil; 3 University of Leeds, Leeds, United Kingdom; 4 National Oceanic and Atmospheric Administration, NOAA, Boulder-Colorado, United States. The Nitrous Oxide (N2O) is the third most important natural greenhouse gas on Earth (WMO, 2016). Globally, the main sources are nitrification and denitrification promoted by microorganisms and it can be natural (~60%) or anthropogenic (~40%) (IPCC, 2007). Approximately two thirds of soil emissions are provided from tropical areas and ~20% of this are from rainforests ecosystems as the region we have studied (Van Haren et al., 2005; Melillo et al. ...
Nature, 2021
Take-down policy If you believe that this document breaches copyright please contact us providing... more Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Atmosphere, 2020
Aircraft atmospheric profiling is a valuable technique for determining greenhouse gas fluxes at r... more Aircraft atmospheric profiling is a valuable technique for determining greenhouse gas fluxes at regional scales (104–106 km2). Here, we describe a new, simple method for estimating the surface influence of air samples that uses backward trajectories based on the Lagrangian model Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT). We determined “regions of influence” on a quarterly basis between 2010 and 2018 for four aircraft vertical profile sites: SAN and ALF in the eastern Amazon, and RBA and TAB or TEF in the western Amazon. We evaluated regions of influence in terms of their relative sensitivity to areas inside and outside the Amazon and their total area inside the Amazon. Regions of influence varied by quarter and less so by year. In the first and fourth quarters, the contribution of the region of influence inside the Amazon was 83–93% for all sites, while in the second and third quarters, it was 57–75%. The interquarter differences are more evident in the...
<p>... more <p>Atmospheric CO<sub>2</sub> concentrations have had a significant increase in recent years reaching levels never seen before. In the Amazon region, the main CO<sub>2</sub> emissions come from land use and cover change (LUCC), especially for the deforestation of natural forests. It is very important to understand the impacts of climate change and deforestation on the Amazon forests to understand their role in the current carbon balance at different scales. The lower-troposphere greenhouse gas (GHG) monitoring program “CARBAM project”, has been collecting bimonthly GHGs vertical profiles in four sites of the Amazon since 2010, filling a very important gap in regional GHGs measurements. Here we compare different LUCC datasets for the Amazon region to see if there is a relation between annual LUCC and bimonthly CO<sub>2</sub> aircraft measurements in the Amazon. We compared the annual (2010-2018) LUCC area from IBGE, PRODES and mapbiomas pan-amazon datasets for each mean influence area of the CARBAM sites and relate this LUCC areas with the annual CO<sub>2 </sub>fluxes. We found differences in the classification methods of the LUCC data, showing differences in the total deforested area. The LUCC data have different tendencies in each CARBAM influence area having more deforestation in the east side of the Amazon CARBAM sites. There is no clear trend between LUCC and carbon fluxes in the last 8 years. Inter-annual CO<sub>2</sub> fluxes variability could be related with the several droughts that influence the photosynthesis/respiration. Here we highlight the scale issues regarding LUCC datasets, atmospheric CO<sub>2</sub> measurements and CO<sub>2</sub> modeling to better understand the current Amazon carbon balance.  </p><p><strong>Acknowledgment:</strong> FAPESP (2018/18493-7; 2018/14006-4; 2016/2016/02018-2), NASA, ERC (GEOCARBON, Horizon 2020/ASICA), NERC (NE/F005806/1), CNPq (480713/2013-8).</p><p> </p>
Atmospheric Measurement Techniques Discussions, 2019
Atmospheric flask samples are either collected at atmospheric pressure by simply opening a valve ... more Atmospheric flask samples are either collected at atmospheric pressure by simply opening a valve of a preevacuated flask, or pressurized with the help of a pump to a few bar above ambient providing large air samples for analysis. Under humid conditions, there is a risk that water vapour in the sample leads to condensation on the walls of the flask, notably at higher than ambient sampling pressures. Liquid water in sample flasks is known to affect the CO 2 mixing ratios and also alters the isotopic composition of oxygen (17 O and 18 O) in CO 2 via isotopic equilibration. Hence, for accurate determination of CO 2 mole fractions and its stable isotopic composition, it is vital to dry the air samples to a sufficiently low dew point before they are pressurized in flasks to avoid condensation. Moreover, the drying system itself should not influence the mixing ratio and the isotopic composition of CO 2 , nor of the other constituents under study. For the "Airborne Stable Isotopes of Carbon from the Amazon" (ASICA) project focusing on accurate measurements of CO 2 and its singlysubstituted stable isotopologues over the Amazon, an air drying system was needed capable of removing water vapour from air sampled at a dew point better than −2 °C, high flow rates up to 12 L/min, and without the need for electrical power. Since to date, no commercial air drying device is available that meets these requirements, we designed and built our own consumable-free, power-free, and portable drying system based on multi-tube Nafion™ gas sample driers (Perma Pure, Lakewood, USA). The required dry purge air is provided by feeding the exhaust flow of the flasks sampling system through a dry molecular sieve (type 3A) cartridge. In this study we describe the systematic evaluation of our Nafion-based air sample dryer with emphasis on its performance concerning the measurements of atmospheric CO2 mole fractions and the three singly-substituted isotopologues of CO 2 (16 O 13 C 16 O, 16 O 12 C 17 O and 16 O 12 C 18 O), as well as the trace gas species CH 4 , CO,
Atmospheric Chemistry and Physics, 2017
Every year, a dense smoke haze covers a large portion of South America originating from fires in ... more 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 CO 2 fluxes at the surface. In this work, we applied a fully integrated atmospheric model to assess the impact of biomass burning aerosols in CO 2 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 CO 2 fluxes, reaching a balance Published by Copernicus Publications on behalf of the European Geosciences Union. 14786 D. S. Moreira et al.: Modeling the radiative effects of biomass burning aerosols 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 CO 2 to the atmosphere.
Philosophical transactions of the Royal Society of London. Series B, Biological sciences, Jan 8, 2018
The outstanding tropical land climate characteristic over the past decades is rapid warming, with... more The outstanding tropical land climate characteristic over the past decades is rapid warming, with no significant large-scale precipitation trends. This warming is expected to continue but the effects on tropical vegetation are unknown. El Niño-related heat peaks may provide a test bed for a future hotter world. Here we analyse tropical land carbon cycle responses to the 2015/16 El Niño heat and drought anomalies using an atmospheric transport inversion. Based on the global atmospheric CO and fossil fuel emission records, we find no obvious signs of anomalously large carbon release compared with earlier El Niño events, suggesting resilience of tropical vegetation. We find roughly equal net carbon release anomalies from Amazonia and tropical Africa, approximately 0.5 PgC each, and smaller carbon release anomalies from tropical East Asia and southern Africa. Atmospheric CO anomalies reveal substantial fire carbon release from tropical East Asia peaking in October 2015 while fires contr...
Atmospheric Chemistry and Physics Discussions, 2017
Every year, a dense smoke haze of regional dimensions covers a large portion of South America ori... more 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…
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Papers by Caio S C Correia