Navegação por Revista "Atmospheric Chemistry and Physics"

Classificar por: Ordenar: Resultados:

  • IPEN-DOC 25711

    MOREIRA, GREGORI de A. ; GUERRERO-RASCADO, JUAN L.; BENAVENT-OLTRA, JOSE A.; ORTIZ-AMEZCUA, PABLO; ROMAN, ROBERTO; BEDOYA-VELASQUEZ, ANDRES E.; BRAVO-ARANDA, JUAN A.; REYES, FRANCISCO J.O.; LANDULFO, EDUARDO ; ALADOS-ARBOLEDAS, LUCAS. Analyzing the turbulent planetary boundary layer by remote sensing systems: the Doppler wind lidar, aerosol elastic lidar and microwave radiometer. Atmospheric Chemistry and Physics, v. 19, n. 2, p. 1263-1280, 2019. DOI: 10.5194/acp-19-1263-2019

    Abstract: The planetary boundary layer (PBL) is the lowermost region of troposphere and is endowed with turbulent characteristics, which can have mechanical and/or thermodynamic origins. This behavior gives this layer great importance, mainly in studies about pollutant dispersion and weather forecasting. However, the instruments usually applied in studies of turbulence in the PBL have limitations in spatial resolution (anemometer towers) or temporal resolution (instrumentation aboard an aircraft). Ground-based remote sensing, both active and passive, offers an alternative for studying the PBL. In this study we show the capabilities of combining different remote sensing systems (microwave radiometer – MWR, Doppler lidar – DL – and elastic lidar – EL) for retrieving a detailed picture on the PBL turbulent features. The statistical moments of the high frequency distributions of the vertical wind velocity, derived from DL, and of the backscattered coefficient, derived from EL, are corrected by two methodologies, namely first lag correction and 􀀀2=3 law correction. The corrected profiles, obtained from DL data, present small differences when compared with the uncorrected profiles, showing the low influence of noise and the viability of the proposed methodology. Concerning EL, in addition to analyzing the influence of noise, we explore the use of different wavelengths that usually include EL systems operated in extended networks, like the European Aerosol Research Lidar Network (EARLINET), Latin American Lidar Network (LALINET), NASA Micro-Pulse Lidar Network (MPLNET) or Skyradiometer Network (SKYNET). In this way we want to show the feasibility of extending the capability of existing monitoring networks without strong investments or changes in their measurements protocols. Two case studies were analyzed in detail, one corresponding to a well-defined PBL and another corresponding to a situation with presence of a Saharan dust lofted aerosol layer and clouds. In both cases we discuss results provided by the different instruments showing their complementarity and the precautions to be applied in the data interpretation. Our study shows that the use of EL at 532 nm requires a careful correction of the signal using the first lag time correction in order to get reliable turbulence information on the PBL.

    Palavras-Chave: boundary layers; troposphere; planetary atmospheres; doppler effect; wind; optical radar; monitoring; microwave radiation; radiometers; aerosols; elastic scattering; remote sensing

    Icon

  • IPEN-DOC 26738

    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

    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

    Icon

  • IPEN-DOC 14494

    LANDULFO, E. ; FREITAS, S.R.; LONGO, K.M.; UEHARA, S.T.; SAWAMURA, P.. A comparison study of regional atmospheric simulations with and elastic backscattering lidar and sunphotometry in an urban area. Atmospheric Chemistry and Physics, v. 9, n. 18, p. 6767-6774, 2009.

    Palavras-Chave: urban areas; atmospheres; simulation; optical radar; backscattering; sun; photometers; air pollution; comparative evaluations

    Icon

  • IPEN-DOC 22700

    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

    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

    Icon

  • IPEN-DOC 26653

    BENAVENT-OLTRA, JOSE A.; ROMAN, ROBERTO; CASQUERO-VERA, JUAN A.; PEREZ-RAMIREZ, DANIEL; LYAMANI, HASSAN; ORTIZ-AMEZCUA, PABLO; BEDOYA-VELASQUEZ, ANDRES E.; MOREIRA, GREGORI de A. ; BARRETO, AFRICA; LOPATIN, ANTON; FUERTES, DAVID; HERRERA, MILAGROS; TORRES, BENJAMIN; DUBOVIK, OLEG; GUERRERO-RASCADO, JUAN L.; GOLOUB, PHILIPPE; OLMO-REYES, FRANCISCO J.; ALADOS-ARBOLEDAS, LUCAS. Different strategies to retrieve aerosol properties at night-time with the GRASP algorithm. Atmospheric Chemistry and Physics, v. 19, n. 22, p. 14149-14171, 2019. DOI: 10.5194/acp-19-14149-2019

    Abstract: This study evaluates the potential of the GRASP algorithm (Generalized Retrieval of Aerosol and Surface Properties) to retrieve continuous day-to-night aerosol properties, both column-integrated and vertically resolved. The study is focused on the evaluation of GRASP retrievals during an intense Saharan dust event that occurred during the Sierra Nevada Lidar aerOsol Profiling Experiment I (SLOPE I) field campaign. For daytime aerosol retrievals, we combined the measurements of the ground-based lidar from EARLINET (European Aerosol Research Lidar Network) station and sun–sky photometer from AERONET (Aerosol Robotic Network), both instruments co-located in Granada (Spain). However, for night-time retrievals three different combinations of active and passive remote-sensing measurements are proposed. The first scheme (N0) uses lidar night-time measurements in combination with the interpolation of sun–sky daytime measurements. The other two schemes combine lidar night-time measurements with nighttime aerosol optical depth obtained by lunar photometry either using intensive properties of the aerosol retrieved during sun–sky daytime measurements (N1) or using the Moon aureole radiance obtained by sky camera images (N2). Evaluations of the columnar aerosol properties retrieved by GRASP are done versus standard AERONET retrievals. The coherence of day-to-night evolutions of the different aerosol properties retrieved by GRASP is also studied. The extinction coefficient vertical profiles retrieved by GRASP are compared with the profiles calculated by the Raman technique at night-time with differences below 30% for all schemes at 355, 532 and 1064 nm. Finally, the volume concentration and scattering coefficient retrieved by GRASP at 2500ma.s.l. are evaluated by in situ measurements at this height at Sierra Nevada Station. The differences between GRASP and in situ measurements are similar for the different schemes, with differences below 30% for both volume concentration and scattering coefficient. In general, for the scattering coefficient, the GRASP N0 and N1 show better results than the GRASP N2 schemes, while for volume concentration, GRASP N2 shows the lowest differences against in situ measurements (around 10 %) for high aerosol optical depth values.

    Palavras-Chave: algorithms; aerosol monitoring; surface properties; dusts; optical properties; optical radar; deserts; aerosol wastes; raman effect

    Icon

  • IPEN-DOC 11678

    TREBS, I.; LARA, L.L.; ZERI, M.; GATTI, LUCIANA V. ; ARTAXO, PAULO; DLUGI, R.; SLANINA, J.; ANDREAE, M.O.; MEIXNER, FRANZ X.. Dry and wet deposition of inorganic nitrogen compounds to a tropical pasture site (Rondonia, Brazil). Atmospheric Chemistry and Physics, v. 6, p. 447-469, 2006.

    Palavras-Chave: nitrogen compounds; washout; deposition; pastures; tropical regions

    Icon

  • IPEN-DOC 22805

    SOUTO-OLIVEIRA, CARLOS E.; ANDRADE, MARIA de F.; KUMAR, PRASHANT; LOPES, FABIO J. da S. ; BABINSKI, MARLY; LANDULFO, EDUARDO . Effect of vehicular traffic, remote sources and new particle formation on the activation properties of cloud condensation nuclei in the megacity of São Paulo, Brazil. Atmospheric Chemistry and Physics, v. 16, p. 14635-14656, 2016. DOI: 10.5194/acp-16-14635-2016

    Abstract: Atmospheric aerosol is the primary source of cloud condensation nuclei (CCN). The microphysics and chemical composition of aerosols can affect cloud development and the precipitation process. Among studies conducted in Latin America, only a handful have reported the impact of urban aerosol on CCN activation parameters such as activation ratio (AR) and activation diameter (D-act). With over 20 million inhabitants, the Metropolitan Area of Sao Paulo (MASP) is the largest megacity in South America. To our knowledge, this is the first study to assess the impact that remote sources and new particle formation (NPF) events have on CCN activation properties in a South American megacity. The measurements were conducted in the MASP between August and September 2014. We measured the CCN within the 0.2-1.0% range of supersaturation, together with particle number concentration (PNC) and particle number distribution (PND), as well as trace-element concentrations and black carbon (BC). NPF events were identified on 35% of the sampling days. Combining multivariate analysis in the form of positive matrix factorization (PMF) with an aerosol profile from lidar and HYSPLIT model analyses allowed us to identify the main contribution of vehicular traffic on all days and sea salt and biomass burning from remote regions on 28 and 21% of the sampling days, respectively. The AR and D-act parameters showed distinct patterns for daytime with intense vehicular traffic and nighttime periods. For example, CCN activation was lower during the daytime than during the nighttime periods, a pattern that was found to be associated mainly with local road-traffic emissions. A decrease in CCN activation was observed on the NPF event days, mainly due to high concentrations of particles with smaller diameters. We also found that aerosols from sea salt, industrial emissions, and biomass burning had minor effects on D-act. For example, nights with biomass burning and vehicular emissions showed slightly lower CCN activation properties than sea-salt, industrial and non-event nights. Our results show that particulate matter from local vehicular emissions during the daytime has a greater effect on CCN activation parameters than that from remote sources.

    Palavras-Chave: clouds; brazil; geography; meteorology; condensation nuclei; elements; trace amounts; gases; ultraviolet radiation; optical radar; atmospheric chemistry

    Icon

  • IPEN-DOC 25148

    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

    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

    Icon

  • IPEN-DOC 24676

    BEDOYA-VELASQUEZ, ANDRES E.; NAVAS-GUZMAN, FRANCISCO; GRANADOS-MUNOZ, MARIA J.; TITOS, GLORIA; ROMAN, ROBERTO; CASQUERO-VERA, JUAN A.; ORTIZ-AMEZCUA, PABLO; BENAVENT-OLTRA, JOSE A.; MOREIRA, GREGORI de A. ; MONTILLA-ROSERO, ELENA; HOYOS, CARLOS D.; ARTINANO, BEGONA; COZ, ESTHER; OLMO-REYES, FRANCISCO J.; ALADOS-ARBOLEDAS, LUCAS; GUERRERO-RASCADO, JUAN L.. Hygroscopic growth study in the framework of EARLINET during the SLOPE I campaign: synergy of remote sensing and in situ instrumentation. Atmospheric Chemistry and Physics, v. 18, n. 10, p. 7001-7017, 2018. DOI: 10.5194/acp-18-7001-2018

    Abstract: This study focuses on the analysis of aerosol hygroscopic growth during the Sierra Nevada Lidar AerOsol Profiling Experiment (SLOPE I) campaign by using the synergy of active and passive remote sensors at the ACTRIS Granada station and in situ instrumentation at a mountain station (Sierra Nevada, SNS). To this end, a methodology based on simultaneous measurements of aerosol profiles from an EARLINET multi-wavelength Raman lidar (RL) and relative humidity (RH) profiles obtained from a multi-instrumental approach is used. This approach is based on the combination of calibrated water vapor mixing ratio (r) profiles from RL and continuous temperature profiles from a microwave radiometer (MWR) for obtaining RH profiles with a reasonable vertical and temporal resolution. This methodology is validated against the traditional one that uses RH from co-located radiosounding (RS) measurements, obtaining differences in the hygroscopic growth parameter (γ) lower than 5 % between the methodology based on RS and the one presented here. Additionally, during the SLOPE I campaign the remote sensing methodology used for aerosol hygroscopic growth studies has been checked against Mie calculations of aerosol hygroscopic growth using in situ measurements of particle number size distribution and submicron chemical composition measured at SNS. The hygroscopic case observed during SLOPE I showed an increase in the particle backscatter coefficient at 355 and 532 nm with relative humidity (RH ranged between 78 and 98 %), but also a decrease in the backscatter-related Ångström exponent (AE) and particle linear depolarization ratio (PLDR), indicating that the particles became larger and more spherical due to hygroscopic processes. Vertical and horizontal wind analysis is performed by means of a co-located Doppler lidar system, in order to evaluate the horizontal and vertical dynamics of the air masses. Finally, the Hänel parameterization is applied to experimental data for both stations, and we found good agreement on γ measured with remote sensing (γ532 = 0.48 ± 0.01 and γ355 = 0.40 ± 0.01) with respect to the values calculated using Mie theory (γ532 = 0.53 ± 0.02 and γ355 = 0.45 ± 0.02), with relative differences between measurements and simulations lower than 9 % at 532 nm and 11 % at 355 nm.

    Palavras-Chave: hygroscopicity; optical radar; atmospheric circulation; aerosols

    Icon

  • IPEN-DOC 22411

    PANDEY, SUDHANSHU; HOUWELING, SANDER; KROL, MAARTEN; AHEN, ILSE; CHEVALLIER, FREDERIC; DLUGOKENCKY, EDWARD J.; GATTI, LUCIANA V. ; GLOOR, EMANUEL; MILLER, JOHN B.; DETMERS, ROB; MACHIDA, TOSHINOBU; ROCKMANN, THOMAS. Inverse modeling of GOSAT-retrieved rations of total column CHsub(4) and COsub(2) for 2009 and 2010. Atmospheric Chemistry and Physics, v. 16, n. 8, p. 5043-5062, 2016.

    Palavras-Chave: simulation; methane; carbon dioxide; comparative evaluations; investigations; greenhouse gases; satellites; limiting values

    Icon

  • IPEN-DOC 12848

    KUHN, U.; ANDREAE, M.O.; AMMANN, C.; ARAUJO, A.C.; BRANCALEONI, E.; CICCIOLI, P.; DINDORF, T.; FRATTONI, M.; GATTI, L.V. ; GANZEVELD, L.; KRUIJT, B.; LLOYD, J.; MEIXNER, F.X.; NOBRE, A.D.; POSCHL, U.; SPIRIG, C.; STEFANI, P.; THIELMANN, A.; VALENTINI, R.; KESSELMEIER, J.. Isoprene and monoterpene fluxes from Central Amazonian rainforest inferred from tower-based and airbone measurements, and implications on the atmospheric chemistry and the local carbon budget. Atmospheric Chemistry and Physics, v. 7, p. 2855-2879, 2007.

    Palavras-Chave: brazil; tropical regions; atmospheric chemistry; forests; particulates; measuring methods; climatic change; carbon; isoprene

    Icon

  • IPEN-DOC 17836

    QUERINO, C.A.S.; SMEETS, C.J.P.P.; VIGANO, I.; HOLZINGER, R.; MOURA, V.; GATTI, L.V. ; MARTINEWSKI, A.; MANZI, A.O.; ARAUJO, A.C. de; ROCKMANN, T.. Methane flux, vertical gradient and mixing ratio measurements in a tropical forest. Atmospheric Chemistry and Physics, v. 11, n. 15, p. 7943-7953, 2011.

    Palavras-Chave: tropical regions; forests; methane; mixing ratio; greenhouse gases

    Icon

  • IPEN-DOC 23086

    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. . Modelling the radiative effects of smoke aerosols on carbon fluxes in Amazon. Atmospheric Chemistry and Physics, p. 14785-14810, 2017. DOI: 10.5194/acp-17-14785-2017

    Abstract: 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.

    Icon

  • IPEN-DOC 23155

    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

    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.

    Icon

  • IPEN-DOC 21298

    MOLLINA, L.; BROQUET, G.; IMBACH, P.; POULTER, B.; BONAL, D.; BURBAN, B.; RAMONET, M.; GATTI, L.V. ; WOFSY, S.C.; MUNGER, J.W.; DLUGOKENCKY, E.; CIAIS, P.. On the ability of a global atmospheric inversion to constrain variations of COsub(@) fluxes over Amazonia. Atmospheric Chemistry and Physics, v. 15, p. 8423-8438, 2015.

    Palavras-Chave: atmospheric chemistry; carbon dioxide; brazil; south america; forests

    Icon

  • IPEN-DOC 11677

    DULI, CHAND; GUYON, PASCAL; ARTAXO, PAULO; SCHMID, OTMAR; FRANK, G.P.; RIZZO, L.V.; MAYOL BRACERO, O.L.; GATTI, LUCIANA V. ; ANDREAE, M.O.. Optical and physical properties of aerosols in the boundary layer and free troposphare over the Amazon Basin during the biomass burning season. Atmospheric Chemistry and Physics, v. 6, p. p. 2911-2925, 2006.

    Palavras-Chave: brazil; amazon river; aerosols; boundary layers; troposphere; carbon monoxide; biomass; seasonal variations; optical properties; physical properties

    Icon

  • IPEN-DOC 12951

    RISSLER, J.; SWIETLICKI, E.; ZHOU, J.; ROBERTS, G.; ANDREAE, M.O.; GATTI, L.V. ; ARTAXO, P.. Physical properties of the sub-micrometer aerosol over the Amazon rain forest during the wet-to-dry season transition - comoparison of modeled and measured CCN concentrations. Atmospheric Chemistry and Physics, v. 4, p. 2119-2143, 2004.

    Palavras-Chave: brazil; forests; climates; seasonal variations; aerosols; physical properties; hygrometry; clouds; aerosol monitoring

    Icon

  • IPEN-DOC 27254

    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

    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

    Icon

  • IPEN-DOC 14865

    D'AMELIO, M.T.S.; GATTI, L.V. ; MILLER, J.B.; TANS, P.. Regional Nsub(2)O fluxes in Amazonia derived from aircraft vertical profiles. Atmospheric Chemistry and Physics, v. 9, n. 22, p. 8785-8797, 2009.

    Palavras-Chave: brazil; nitrous oxide; greenhouse gases; aircraft; biomass; burnup

    Icon

  • IPEN-DOC 11679

    SCHMID, OTMAR; ARTAXO, PAULO; ARNOTT, PATRICK W.; DULI, CHAND; GATTI, LUCIANA V. ; FRANK, G.P.; HOFFER, A.; SCHNAITER, M.; ANDREAE, M.O.. Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin. I: Comparison and field calibration of absorption measurement techniques. Atmospheric Chemistry and Physics, v. 6, p. p. 3443-3462, 2006.

    Palavras-Chave: amazon river; biomass; aerosols; absorption spectra; light sources; measuring instruments; photometers

    Icon

A pesquisa no RD utiliza os recursos de busca da maioria das bases de dados. No entanto algumas dicas podem auxiliar para obter um resultado mais pertinente.

É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

A pesquisa apresentará melhor resultado selecionando um dos filtros disponíveis em Navegar

Os filtros disponíveis em Navegar tais como: Coleções, Ano de publicação, Títulos, Assuntos, Autores, Revista, Tipo de publicação são autoexplicativos. O filtro, Autores IPEN apresenta uma relação com os autores vinculados ao IPEN; o ID Autor IPEN diz respeito ao número único de identificação de cada autor constante no RD e sob o qual estão agrupados todos os seus trabalhos independente das variáveis do seu nome; Tipo de acesso diz respeito à acessibilidade do documento, isto é , sujeito as leis de direitos autorais, ID RT apresenta a relação dos relatórios técnicos, restritos para consulta das comunidades indicadas.

A opção Busca avançada utiliza os conectores da lógica boleana, é o melhor recurso para combinar chaves de busca e obter documentos relevantes à sua pesquisa, utilize os filtros apresentados na caixa de seleção para refinar o resultado de busca. Pode-se adicionar vários filtros a uma mesma busca.

Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, bibl@ipen.br .

Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.