GIOVANNI SOUZA
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Resumo IPEN-doc 30951 Exploring the impact of cirrus clouds in São Paulo2024 - SOUZA, GIOVANNI; BARJA, BORIS; LOPES, FABIO J.S.; LANDULFO, EDUARDO; BECA, TOMAS; VAUGHAN, MARK A.Cirrus clouds play a role in the greenhouse effect by interacting with the outgoing thermal radiation released by the Earth's surface. There has been a growing interest in studying these clouds in recent decades, and scientists globally have been gathering data on their physical and optical characteristics. Understanding their impact on climate is crucial for improvements in atmospheric models. The positive impact of cirrus clouds on the radiative budget is attributed to their thickness and their ability to allow shortwave solar radiation while blocking longwave radiation emitted from the surface. These clouds have extensive coverage across the globe, particularly in tropical regions, significantly influencing the climate. This study presents an extensive analysis of cirrus cloud characteristics in the São Paulo state region using data collected by the CALIPSO satellite over eleven years (2007-2017). The investigation covers various aspects of cirrus clouds, including their distribution, altitude, thickness, temperature, and optical properties. Yearly distributions reveal prevalent cirrus clouds occurring between 10 and 15 km, with little variations over the years. Monthly distributions highlight seasonal dynamics in base and top altitudes, while cirrus thickness remains relatively consistent. This study explores cirrus cloud optical depth (COD), showing variations across different thicknesses. This research aims to contribute to a deeper understanding of cirrus cloud behavior in South America and its implications for atmospheric processes.Resumo IPEN-doc 30950 Evaluation of the impacts of stratospheric aerosols on São Paulo after the 2019-2020 wildfires in Australia (Black Summer)2024 - LOPES, PEROLA P.Q.; MELLO, LUISA D.; SOUZA, GIOVANNI; LOPES, FABIO J.S.; MOREIRA, GREGORI de A.; LANDULFO, EDUARDOIn August 2019, a series of wildfires erupted in Australia, later termed "Black Summer," rapidly spreading across various states and consuming a total area of approximately 103,000 square kilometers. This study employed the MSP-Lidar I, an advanced remote sensing system, to analyze aerosol disturbances in the stratosphere above São Paulo, with a focus on altitudes ranging from 15-30 km during January 2020. Through lidar measurements at three different wavelengths, we successfully identified and analyzed the vertical dispersion of aerosol plumes. By utilizing atmospheric modeling, HYSPLIT, the study traced the path of these plumes across the Pacific Ocean to São Paulo. The analysis revealed three distinct plumes at specific altitudes, all originating from the regions affected by the Australian wildfires. This research underscores the effectiveness of the MSP-Lidar I in tracking complex atmospheric phenomena and significantly enhances our understanding of the long-term dynamics of aerosol dispersion. These findings are crucial for air quality and global climate change studies, as they underscore the far-reaching transcontinental impacts of large-scale wildfires. The study highlights the urgent need for international collaboration in monitoring and mitigating the effects of such fires on global atmospheric conditions.Artigo IPEN-doc 30209 Comparison of PBL heights from ceilometer measurements and greenhouse gases concentrations in São Paulo2023 - SANTOS, AMANDA V. dos; ARAUJO, ELAINE C.; ANDRADE, IZABEL da S.; CORREA, THAIS; MARQUES, MARCIA T.A.; SOUTO-OLIVEIRA, CARLOS E.; LEONARDO, NOELE F.; MACEDO, FERNANDA de M.; SOUZA, GIOVANNI; LOPES, PEROLA P. de Q.; MOREIRA, GREGORI de A.; ANDRADE, MARIA de F.; LANDULFO, EDUARDOThis paper presents a study conducted in São Paulo, Brazil, where the planetary boundary layer height (PBLH) was determined using ceilometer data and the wavelet covariance transform method. The retrieved PBLH values were subsequently compared with the concentrations of CO2 and CH4 measured at three distinct experimental sites in the city. The period of study was July 2021. This study also included a comparison between ceilometer data and lidar data, which demonstrated the favorable applicability of the ceilometer data for PBLH estimation. An examination of the correlation between changes in average CO2 concentrations and PBLH values revealed stronger correlations for the IAG and UNICID stations, with correlation coefficients (ρ) of approximately −0.86 and −0.85, respectively, in contrast to the Pico do Jaraguá station, which exhibited a lower correlation coefficient of −0.42. When assessing changes in CH4 concentrations against variations in PBL height, the retrieved correlation coefficients were approximately −0.78 for IAG, −0.66 for UNICID, and −0.38 for Pico do Jaraguá. The results indicated that CO2/CH4 concentrations are negatively correlated with PBL heights, with CO2 concentrations showing more significant correlation than CH4 . Additionally, among the three measurement stations, IAG measurements displayed the most substantial correlation. The results from this study contribute to the understanding of the relationship between PBLH and greenhouse gas concentrations, emphasizing the potential of remote sensing systems like ceilometers in monitoring and studying atmospheric processes.Dissertação IPEN-doc 29775 Study of cirrus clouds physical properties over the state of São Paulo, Brazil, from CALIPSO/CALIOP level 2 data2023 - SOUZA, GIOVANNISatellite measurements have made an enormous contribution to the development of scientific knowledge. By providing data on atmospheric components over large areas and long periods of time, these instruments have enabled researchers to gain a much deeper understanding of the environment. In this study, we analyzed level 2 data from the CALIPSO/CALIOP satellite to investigate the physical and optical characteristics of cirrus clouds in the state of São Paulo between 2007 and 2017. The study showed that cirrus is the most present type of cloud in the region, and they mainly form at altitudes between 10 km and 14 km, and average thickness of 1.4 km. They form at low temperatures, typically less than -40°C. The analysis of the seasonal characteristics showed that the frequency of occurrence of cirrus clouds increase during summer, and coincide with the formation of convective clouds due to the formation of cirrus from anvil clouds. The optical depth analysis revealed that the most common type of cirrus is thick (optical depth > 0.3), with a overall frequency of occurrence above 45%. These results provide valuable insights into the behavior of cirrus clouds in the region and demonstrate the important role that satellite measurements can play in advancing our understanding of the atmosphere.Resumo IPEN-doc 28969 Study of optical properties and spatial distribution of cirrus clouds over São Paulo, Brazil, using CALIPSO level 2 data2021 - SOUZA, GIOVANNI; LOPES, FABIO J.S.; LANDULFO, EDUARDOCirrus clouds have an important role in the earth’s radiation budget, they have a wide spatial extension and are the most present type of clouds in the atmosphere, especially in tropical regions (Sassen et al., 2018). Due their thickness, Cirrus clouds are almost transparent for the incoming shortwave solar radiation and opaque to the longwave emitted by the planet's surface. Despite the importance of Cirrus clouds in the earth’s climate, there is a lack of studies focused on this type of cloud in the southern hemisphere. Since 2006, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), a joint mission between NASA and the French space agency, CNES, provides physical and optical information of clouds and aerosols to improve the understanding of their role in the climate, air quality and radiation budget in the Earth. The primary instrument of CALIPSO payload is the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), which is a lidar system operating on 1064 nm and 532 nm (with parallel and perpendicular polarization) wavelengths. CALIOP provides as level 1 data, high-resolution vertical profiles of aerosols and clouds. In turn, the level 2 data provides processed products such as cloud-aersol discrimination, cloud base and top layer altitude, and cloud optical depth. The aim of this work is use the CALIOP global coverage to study the physical and optical properties of Cirrus clouds over the São Paulo State (roughly centered on 21.3°S, 50.3°W), in Brazil. We have employed a statistic analysis of 9 years (2007-2015) of data using the level 2 products to obtain spatial distribution and optical properties of cirrus clouds over São Paulo state, in order to understanding the long-term trend of Cirrus clouds coverage in the São Paulo state and later on Brazil.