GREGORI DE ARRUDA MOREIRA

GREGORI DE ARRUDA MOREIRA

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Performance assessment of aerosol-lidar remote sensing skills to retrieve the time evolution of the urban boundary layer height in the Metropolitan Region of São Paulo City, Brazil
2022 - MOREIRA, GREGORI de A.; OLIVEIRA, AMAURI P. de; SANCHEZ, MACIEL P.; CODATO, GEORGIA; LOPES, FABIO J. da S.; LANDULFO, EDUARDO; MARQUES FILHO, EDSON P.
This paper investigates the performance of seven methods of retrieving the planetary boundary layer height (PBLH) from lidar measurements carried out in the Metropolitan Region of S˜ao Paulo (MRSP) during two MCITY-BRAZIL field campaigns of 2013. The performance is objectively assessed considering as reference the PBLH retrieved from rawinsonde carried out every 3 h during these campaigns. The role of clouds and aerosol load in the performance of the seven methods is analysed considering three case study scenarios representative of typical atmospheric conditions in the MRSP: (a) winter clean atmosphere, (b) summer low clouds and aerosol multilayers, (c) summer sea-breeze intrusion. Corroborating the case study results, the objective analysis indicated that most of the lidar methods retrieved PBLH closer to the top of the entrainment zone than the mixed layer, contradicting their definition. During daytime, the Wavelet Covariance Transform Method performs better than all the other six methods. The Inflexion Point Method performed better to estimate the Residual Layer height during night-time. In average, the diurnal evolution of the PBLH and its local rate of change based on lidar and rawinsonde measurements are in agreement.
Study of the planetary boundary layer height in an urban environment using a combination of microwave radiometer and ceilometer
2020 - MOREIRA, GREGORI de A.; GUERRERO-RASCADO, JUAN L.; BRAVO-ARANDA, JUAN A.; FOYO-MORENO, INMACULADA; CAZORLA, ALBERTO; ALADOS, INMACULADA; LYAMANI, HASSAN; LANDULFO, EDUARDO; ALADOS-ARBOLEDAS, LUCAS
The Planetary Boundary Layer (PBL) is an important part of the atmosphere that is relevant in different atmospheric fields like pollutant dispersion, and weather forecasting. In this study, we analyze four and five-year datasets of measurements gathered with a ceilometer and a microwave radiometer to study the PBL structure respectively, in the mid-latitude urban area of Granada (Spain). The methodologies applied for the PBL Height (PBLH) detection (gradient method for ceilometer and the combination of parcel method and temperature gradient method for microwave radiometer) provided a description in agreement with the literature about the PBL structure under simple scenarios. Then, the PBLH behavior is characterized by a statistical study of the convective and stable situations, so that the PBLH was obtained from microwave radiometer measurements. The analysis of the PBLH statistical study shows some agreement with other PBLH studies such as daily pattern and yearly cycle, and the discrepancies were explained in terms of distinct latitudes, topography and climate conditions. Finally, it was performed a joint long-term analysis of the residual layer (RL) provided by ceilometer and the stable and convective layer heights determined by microwave radiometer, offering a complete picture of the PBL evolution by synergetic combination of remote sensing techniques. The PBL behavior has been used for explaining the daily cycle of Black Carbon (BC) concentration, used as tracer of the pollutants emissions associated to traffic.
Seasonal analysis of the atmosphere during five years by using microwave radiometry over a mid-latitude site
2019 - BEDOYA-VELASQUEZ, ANDRES E.; NAVAS-GUZMAN, FRANCISCO; MOREIRA, GREGORI de A.; ROMAN, ROBERTO; CAZORLA, ALBERTO; ORTIZ-AMEZCUA, PABLO; BENAVENT-OLTRA, JOSE A.; ALADOS-ARBOLEDAS, LUCAS; OLMO-REYES, FRANCISCO J.; FOYO-MORENO, INMACULADA; MONTILLA-ROSERO, ELENA; HOYOS, CARLOS D.; GUERRERO-RASCADO, JUAN L.
This work focuses on the analysis of the seasonal cycle of temperature and relative humidity (RH) profiles and integrated water vapor (IWV) obtained from microwave radiometer (MWR) measurements over the mid-latitude city of Granada, southern Spain. For completeness the study, the maximum atmospheric boundary layer height (ABLHmax) is also included. To this end, we have firstly characterized the HATPRO-RPG MWR errors using 55 colocated radiosondes (RS) by means of the mean-bias (bias) profile and the standard deviation (SDbias) profile classified under all-weather conditions and cloud-free conditions. This characterization pointed out that temperature from HATPRO-MWR presents a very low bias respects RS mostly below 2.0 km agl, ranging from positive to negative values under all-weather conditions (from 1.7 to −0.4 K with SDbias up to 3.0 K). Under cloud-free conditions, the bias was very similar to that found under allweather conditions (1.8 to −0.4 K) but with smaller SDbias (up to 1.1 K). The same behavior is also seen in this lower part (ground to 2.0 km agl) for RH. Under all-weather conditions, the mean RH bias ranged from 3.0 to −4.0% with SDbias between 10 and 16.3% while under cloud-free conditions the bias ranged from 2.0 to −0.4% with SDbias from 0.5 to 13.3%. Above 2.0 km agl, the SDbias error increases considerably up to 4 km agl (up to −20%), and then decreases slightly above 7.0 km agl (up to−5%). In addition, IWV values from MWR were also compared with the values obtained from the integration of RS profiles, showing a better linear fit under cloudfree conditions (R2=0.96) than under all-weather conditions (R2=0.82). The mean bias under cloud-free conditions was −0.80 kg/m2 while for all-weather conditions it was −1.25 kg/m2. Thus, the SDbiasfor all the statistics (temperature, RH and IWV) of the comparison between MWR and RS presented higher values for allweather conditions than for cloud-free conditions ones. It points out that the presence of clouds is a key factor to take into account when MWR products are used. The second part of this work is devoted to a seasonal variability analysis over five years, leading us to characterize thermodynamically the troposphere over our site. This city atmosphere presents a clear seasonal cycle where temperature, ABLHmax and IWV increase from winter to summer and decrease in autumn, meanwhile RH decreases along the warmer seasons. This city presents cold winters (mean daily maximum temperature: 10.6 ± 1.1 °C) and dry/hot summers (mean daily maximum temperature of 28.8 ± 0.9 °C and mean daily maximum of surface RH up to 55.0 ± 6.0%) at surface (680m asl). Moreover, considering temporal trends, our study pointed out that only temperature and RH showed a linear increase in winters with a mean-rate of (0.5 ± 0.1) °C/year and (3.4 ± 1.7) %/year, respectively, from ground to 2.0 km agl, meanwhile IWV presented a linear increase of 1.0 kg·m−2/year in winters, 0.78 kg·m−2/year in summers and a linear decrease in autumns of −0.75 kg·m−2/year.
Study of the planetary boundary layer by microwave radiometer, elastic lidar and Doppler lidar estimations in Southern Iberian Peninsula
2018 - 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, LUCAS
The 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).
Sources and physicochemical characteristics of submicron aerosols during three intensive campaigns in Granada (Spain)
2018 - AGUILA, A. del; SORRIBAS, M.; LYAMANI, H.; TITOS, G.; OLMO, F.J.; ARRUDA-MOREIRA, G.; YELA, M.; ALADOS-ARBOLEDAS, L.
Aerosol particles in the submicron range and their physicochemical characteristics were investigated for the first time in Granada, southeastern Iberian Peninsula, during three intensive campaigns. The physical and chemical characteristics were analysed during two spring campaigns and one autumn campaign. New particle formation (NPF) events were found to be more frequent in spring than in autumn. The mean duration, growth rates and maximum diameters had ranges of 5.3–13.2 h, 2.4–4.0 nm h−1 and 35–47 nm, respectively. In addition, one shrinkage event occurred and had a duration of 2.2 h and a shrinkage rate of −2.5 nm h−1. During a period of atmospheric stagnation conditions under the influence of mountain breezes, three consecutive NPF events occurred. The high frequency of the NPF events was attributed to higher temperature and radiation levels and lower relative humidity than during a previous day with similar stagnant conditions but no nucleation occurrence. According to correlation analysis, mineral components correlated with particle number in the Aitken mode, while metals and secondary inorganic aerosols correlated with particle number in the finer and larger fractions, respectively. Pollutants such as CO, NO2, NO and black carbon showed moderate and high correlations with particle number in the submicron fraction. To assess the impact of the particle number contribution according to sources, a new approach was introduced using black carbon concentrations, resulting in four major contributors: urban background, traffic, NPF and biomass burning. The proposed approach was validated by means of different models based on the aerosol spectral dependencies and chemical compositions that classify aerosol populations. Both the models and the proposed approach identified biomass burning and fossil fuel particles during the same periods, and the results showed good agreement. The proposed approach can guide future studies attempting to account for submicron particle contributions in other urban environments.