Abstract: Central Amazonia serves as an ideal location to study atmospheric particle formation, since it often represents nearly natural, pre-industrial conditions but can also experience periods of anthropogenic influence due to the presence of emissions from large metropolitan areas like Manaus, Brazil. Ultrafine (sub-100 nm diameter) particles are often observed in this region, although new particle formation events seldom occur near the ground despite being readily observed in other forested regions with similar emissions of volatile organic compounds (VOCs). This study focuses on identifying the chemical composition of ultrafine particles as a means of determining the chemical species and mechanisms that may be responsible for new particle formation and growth in the region. These measurements were performed during the wet season as part of the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/ 5) field campaign at a site located 70 km southwest of Manaus. A thermal desorption chemical ionization mass spectrometer (TDCIMS) characterized the most abundant compounds detected in ultrafine particles. Two time periods representing distinct influences on aerosol composition, which we label as “anthropogenic” and “background” periods, were studied as part of a larger 10 d period of analysis. Higher particle number concentrations were measured during the anthropogenic period, and modeled back-trajectory frequencies indicate transport of emissions from the Manaus metropolitan area. During the background period there were much lower number concentrations, and back-trajectory frequencies showed that air masses arrived at the site predominantly from the forested regions to the north and northeast. TDCIMS-measured constituents also show distinct differences between the two observational periods. Although bisulfate was detected in particles throughout the 10 d period, the anthropogenic period had higher levels of particulate bisulfate overall. Ammonium and trimethyl ammonium were positively correlated with bisulfate. The background period had distinct diurnal patterns of particulate cyanate and acetate, while oxalate remained relatively constant during the 10 d period. 3-Methylfuran, a thermal decomposition product of a particulate-phase isoprene epoxydiol (IEPOX), was the dominant species measured in the positive-ion mode. Principal component analysis (PCA) was performed on the TDCIMS-measured ion abundance and aerosol mass spectrometer (AMS) mass concentration data. Two different hierarchical clusters representing unique influences arise: one comprising ultrafine particulate acetate, hydrogen oxalate, cyanate, trimethyl ammonium and 3-methylfuran and another made up of ultrafine particulate bisulfate, chloride, ammonium and potassium. A third cluster separated AMS-measured species from the two TDCIMS-derived clusters, indicating different sources or processes in ultrafine aerosol particle formation compared to larger submicron-sized particles.

Palavras-Chave: aerosols; atmospheric circulation; particles; amazon river; mass spectrometers; chemical composition; meteorology

GLICKER, HAYLEY S.; LAWLER, MICHAEL J.; ORTEGA, JOHN; SA, SUZANE S. de; MARTIN, SCOT T.; ARTAXO, PAULO; BUSTILLOS, OSCAR V.; SOUZA, RODRIGO de; TOTA, JULIO; CARLTON, ANNMARIE; SMITH, JAMES N. Chemical composition of ultrafine aerosol particles in central Amazonia during the wet season. Atmospheric Chemistry and Physics, v. 19, n. 20, p. 13053-13066, 2019. DOI: 10.5194/acp-19-13053-2019. Disponível em: http://repositorio.ipen.br/handle/123456789/30932. Acesso em: $DATA.

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Abstract: We 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.

Palavras-Chave: methane; carbon dioxide; satellites; south america; brazil; simulation

FENG, LIANG; PALMER, PAUL I.; BÖSCH, 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, ANDREAS. Consistent regional fluxes of CHsub(4) and COsub(2) inferred from GOSAT proxy XCHsub(4)XCOsub(2) retrievals, 2010-2014. Atmospheric Chemistry and Physics, v. 17, n. 7, p. 4781-4797, 2017. DOI: 10.5194/acp-17-4781-2017. Disponível em: http://repositorio.ipen.br/handle/123456789/26757. Acesso em: $DATA.

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Abstract: The precise contribution of the two major sinks for anthropogenic CO2 emissions, terrestrial vegetation and the ocean, and their location and year-to-year variability are not well understood. Top-down estimates of the spatiotemporal variations in emissions and uptake of CO2 are expected to benefit from the increasing measurement density brought by recent in situ and remote CO2 observations.We uniquely apply a batch Bayesian synthesis inversion at relatively high resolution to in situ surface observations and bias-corrected GOSAT satellite column CO2 retrievals to deduce the global distributions of natural CO2 fluxes during 2009–2010. The GOSAT inversion is generally better constrained than the in situ inversion, with smaller posterior regional flux uncertainties and correlations, because of greater spatial coverage, except over North America and northern and southern high-latitude oceans. Complementarity of the in situ and GOSAT data enhances uncertainty reductions in a joint inversion; however, remaining coverage gaps, including those associated with spatial and temporal sampling biases in the passive satellite measurements, still limit the ability to accurately resolve fluxes down to the sub-continental or subocean basin scale. The GOSAT inversion produces a shift in the global CO2 sink from the tropics to the north and south relative to the prior, and an increased source in the tropics of 2 PgC yr􀀀1 relative to the in situ inversion, similar to what is seen in studies using other inversion approaches. This result may be driven by sampling and residual retrieval biases in the GOSAT data, as suggested by significant discrepancies between posterior CO2 distributions and surface in situ and HIPPO mission aircraft data. While the shift in the global sink appears to be a robust feature of the inversions, the partitioning of the sink between land and ocean in the inversions using either in situ or GOSAT data is found to be sensitive to prior uncertainties because of negative correlations in the flux errors. The GOSAT inversion indicates significantly less CO2 uptake in the summer of 2010 than in 2009 across northern regions, consistent with the impact of observed severe heat waves and drought. However, observations from an in situ network in Siberia imply that the GOSAT inversion exaggerates the 2010–2009 difference in uptake in that region, while the prior CASA-GFED model of net ecosystem production and fire emissions reasonably estimates that quantity. The prior, in situ posterior, and GOSAT posterior all indicate greater uptake over North America in spring to early summer of 2010 than in 2009, consistent with wetter conditions. The GOSAT inversion does not show the expected impact on fluxes of a 2010 drought in the Amazon; evaluation of posterior mole fractions against local aircraft profiles suggests that time-varying GOSAT coverage can bias the estimation of interannual flux variability in this region.

Palavras-Chave: satellites; greenhouse gases; carbon dioxide; in-situ processing; satellite atmospheres; controlled atmospheres

WANG, JAMES S.; KAWA, S.R.; COLLATZ, G.J.; SASAKAWA, MOTOKI; GATTI, LUCIANA V.; MACHIDA, TOSHINOBU; LIU, YUPING; MANYIN, MICHAEL E. A global synthesis inversion analysis of recent variability in CO2 fluxes using GOSAT and in situ observations. Atmospheric Chemistry and Physics, v. 18, n. 15, p. 11097-11124, 2018. DOI: 10.5194/acp-18-11097-2018. Disponível em: http://repositorio.ipen.br/handle/123456789/29355. Acesso em: $DATA.

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Abstract: The automatic and non-supervised detection of the planetary boundary layer height (z(PBL)) by means of lidar measurements was widely investigated during the last several years. Despite considerable advances, the experimental detection still presents difficulties such as advected aerosol layers coupled to the planetary boundary layer (PBL) which usually produces an overestimation of the z(PBL). To improve the detection of the z(PBL) in these complex atmospheric situations, we present a new algorithm, called POLARIS (PBL height estimation based on lidar depolarisation). POLARIS applies the wavelet covariance transform (WCT) to the range-corrected signal (RCS) and to the perpendicular-to-parallel signal ratio (delta) profiles. Different candidates for z(PBL) are chosen and the selection is done based on the WCT applied to the RCS and delta. We use two ChArMEx (Chemistry-Aerosol Mediterranean Experiment) campaigns with lidar and microwave radiometer (MWR) measurements, conducted in 2012 and 2013, for the POLARIS' adjustment and validation. POLARIS improves the z(PBL) detection compared to previous methods based on lidar measurements, especially when an aerosol layer is coupled to the PBL. We also compare the z(PBL) provided by the Weather Research and Forecasting (WRF) numerical weather prediction (NWP) model with respect to the z(PBL) determined with POLARIS and the MWR under Saharan dust events. WRF underestimates the z(PBL) during daytime but agrees with the MWR during night-time. The z(PBL) provided by WRF shows a better temporal evolution compared to the MWR during daytime than during night-time.

Palavras-Chave: boundary layers; planetary atmospheres; layers; atmospheric circulation; aerosols

BRAVO-ARANDA, JUAN A.; MOREIRA, GREGORI de A.; NAVAS-GUZMAN, FRANCISCO; GRANADOS-MUNOZ, MARIA J.; GUERRERO-RASCADO, JUAN L.; POZO-VAZQUEZ, DAVID; ARBIZU-BARRENA, CLARA; REYES, FRANCISCO J.O.; MALLET, MARC; ARBOLEDAS, LUCAS A. A new methodology for PBL height estimations based on lidar depolarization measurements: analysis and comparison against MWR and WRF model-based results. Atmospheric Chemistry and Physics, v. 17, n. 11, p. 6839-6851, 2017. DOI: 10.5194/acp-17-6839-2017. Disponível em: http://repositorio.ipen.br/handle/123456789/27832. Acesso em: $DATA.

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Abstract: Biogenic volatile organic compounds (BVOCs) are important components of the atmosphere due to their contribution to atmospheric chemistry and biogeochemical cycles. Tropical forests are the largest source of the dominant BVOC emissions (e.g. isoprene and monoterpenes). In this study, we report isoprene and total monoterpene flux measurements with a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) using the eddy covariance (EC) method at the Tapajós National Forest (2.857∘ S, 54.959∘ W), a primary rainforest in eastern Amazonia. Measurements were carried out from 1 to 16 June 2014, during the wet-to-dry transition season. During the measurement period, the measured daytime (06:00–18:00 LT) average isoprene mixing ratios and fluxes were 1.15±0.60 ppb and 0.55±0.71 mg C m−2 h−1, respectively, whereas the measured daytime average total monoterpene mixing ratios and fluxes were 0.14±0.10 ppb and 0.20±0.25 mg C m−2 h−1, respectively. Midday (10:00–14:00 LT) average isoprene and total monoterpene mixing ratios were 1.70±0.49 and 0.24±0.05 ppb, respectively, whereas midday average isoprene and monoterpene fluxes were 1.24±0.68 and 0.46±0.22 mg C m−2 h−1, respectively. Isoprene and total monoterpene emissions in Tapajós were correlated with ambient temperature and solar radiation. Significant correlation with sensible heat flux, SHF (r2=0.77), was also observed. Measured isoprene and monoterpene fluxes were strongly correlated with each other (r2=0.93). The MEGAN2.1 (Model of Emissions of Gases and Aerosols from Nature version 2.1) model could simulate most of the observed diurnal variations (r2=0.7 to 0.8) but declined a little later in the evening for both isoprene and total monoterpene fluxes. The results also demonstrate the importance of site-specific vegetation emission factors (EFs) for accurately simulating BVOC fluxes in regional and global BVOC emission models.

Palavras-Chave: organic compounds; volatility; atmospheres; data covariances; measuring instruments; atmospheric chemistry; large-eddy simulation; volatile matter; amazon river

SARKAR, CHINMOY; GUENTHER, ALEX B.; PARK, JEONG-HOO; SECO, ROGER; ALVES, ELIANE; BATALHA, SARAH; SANTANA, RAONI; KIM, SAEWUNG; SMITH, JAMES; TOTA, JULIO; VEGA, OSCAR. PTR-TOF-MS eddy covariance measurements of isoprene and monoterpene fluxes from an eastern Amazonian rainforest. Atmospheric Chemistry and Physics, v. 20, n. 12, p. 7179-7191, 2020. DOI: 10.5194/acp-20-7179-2020. Disponível em: http://repositorio.ipen.br/handle/123456789/31480. Acesso em: $DATA.

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Abstract: 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.

Palavras-Chave: carbon; emission; satellites; fires; satellite atmospheres; carbon monoxide; forests; amazon river

NAUS, STIJN; DOMINGUES, LUCAS G.; KROL, MAARTEN; LUIJKX, INGRID T.; GATTI, LUCIANA V.; MILLER, JOHN B.; GLOOR, EMANUEL; BASU, SOURISH; CORREIA, CAIO; KOREN, GERBRAND; WORDEN, HELEN M.; FLEMMING, JOHANNES; PETRON, GABRIELLE; PETERS, WOUTER. Sixteen years of MOPITT satellite data strongly constrain Amazon CO fire emissions. Atmospheric Chemistry and Physics, v. 22, n. 22, p. 14735-14750, 2022. DOI: 10.5194/acp-22-14735-2022. Disponível em: http://repositorio.ipen.br/handle/123456789/33860. Acesso em: $DATA.

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