GREGORI DE ARRUDA MOREIRA
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Artigo IPEN-doc 25711 Analyzing the turbulent planetary boundary layer by remote sensing systems2019 - 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, LUCASThe 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.Artigo IPEN-doc 25115 Study of the planetary boundary layer by microwave radiometer, elastic lidar and Doppler lidar estimations in Southern Iberian Peninsula2018 - MOREIRA, GREGORI de A.; GUERRERO-RASCADO, JUAN L.; BRAVO-ARANDA, JUAN A.; BENAVENT-OLTRA, JOSE A.; ORTIZ-AMEZCUA, PABLO; ROMAN, ROBERTO; BEDOYA-VELASQUEZ, ANDRES E.; LANDULFO, EDUARDO; ALADOS-ARBOLEDAS, LUCASThe Planetary Boundary Layer (PBL) is a relevant part of the atmosphere with a variable extension that clearly plays an important role in fields like air quality or weather forecasting. Passive and active remote sensing systems have been widely applied to analyze PBL characteristics. The combination of different remote sensing techniques allows obtaining a complete picture on the PBL dynamic. In this study, we analyze the PBL using microwave radiometer, elastic lidar and Doppler lidar data. We use co-located data simultaneously gathered in the framework of SLOPE-I (Sierra Nevada Lidar aerOsol Profiling Experiment) campaign at Granada (Spain) during a 90- day period in summer 2016. Firstly, the PBL height (PBLH) obtained from microwave radiometer data is validated against PBLH provided by analyzing co-located radiosondes, showing a good agreement. In a second stage, active remote sensing systems are used for deriving the PBLH. Thus, an extended Kalman filter method is applied to data obtained by the elastic lidar while the vertical wind speed variance method is applied to the Doppler lidar. PBLH′s derived by these approaches are compared to PBLH retrieved by the microwave radiometer. The results show a good agreement among these retrievals based on active remote sensing in most of the cases, although some discrepancies appear in instances of intense PBL changes (either growth and/or decrease).Artigo IPEN-doc 24756 Estimating the planetary boundary layer height from radiosonde and doppler lidar measurements in the city of São Paulo - Brazil2018 - MARQUES, MARCIA T.A.; MOREIRA, GREGORI de A.; PINERO, MACIEL; OLIVEIRA, AMAURI P.; LANDULFO, EDUARDOThis study aims to compare the planetary boundary layer height (PBLH) values estimated by radiosonde data through the bulk Richardson number (BRN) method and by Doppler lidar measurements through the Carrier to Noise Ratio (CNR) method, which corresponds to the maximum of the variance of CNR profile. The measurement campaign was carried during the summer of 2015/2016 in the city of São Paulo. Despite the conceptual difference between these methods, the results show great agreement between them.Artigo IPEN-doc 23155 A new methodology for PBL height estimations based on lidar depolarization measurements: analysis and comparison against MWR and WRF model-based results2017 - 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.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.Artigo IPEN-doc 20746 Comparison between two algorithms based on different wavelets to obtain the planetary boundary layer height2014 - MOREIRA, GREGORI de A.; LOPES, FABIO J. da S.; GUERRERO RASCADO, JUAN L.; GRANADOS MUNOZ, MARIA J.; BOURAYOU, RIAD; LANDULFO, EDUARDOResumo IPEN-doc 19736 A comparison between image methods and WRF model in determination the top of atmospheric boundary layer2013 - MOREIRA, GREGORI de A.; LANDULFO, EDUARDO; SANTIAGO, ALEXANDRE M.; SALVADOR, NADIR; LORIATO, AYRES G.; ALBUQUERQUE, TACIANA T. de A.; REIS JUNIOR, NEYVAL C.