Banca de DEFESA: NARA POLIANA MENESES DE OLIVEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : NARA POLIANA MENESES DE OLIVEIRA
DATA : 07/05/2018
HORA: 08:30
LOCAL: Auditório do CCET
TÍTULO:

VALIDATION OF THE CALIPSO LIDAR RATIO USING AEROSOL OPTICAL DEPTH  OBTAINED FROM A SUN PHOTOMETER  IN PETROLINA/PE, BRAZIL

PALAVRAS-CHAVES:

Aerosol Optical Depth, CALIPSO, AERONET, LIDAR

PÁGINAS: 75
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Meteorologia
ESPECIALIDADE: Sensoriamento Remoto da Atmosfera
RESUMO:

There are many factors that turn the quantification of the aerosol’s influence on climate change processes challenging. These factors are associated to the uncertainties in the distribution and properties of aerosols and clouds, as well as their global interactions. With the purpose of reducing those uncertainties, the National Aeronautics and Space Administration (NASA) in collaboration with the Centre National d'Études Spatiales (CNES), launched the Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, that has on board a Cloud-Aerosol LIDAR with Orthogonal Polarization (CALIOP), consisting of a light detector and tracker Light Detection and Ranging (LIDAR). This system performs a vertical sounding of thin clouds and aerosols properties around the globe as the satellite passes. The optical properties of the atmosphere along the pathway where the CALIOP laser propagates, are recovered by a number of algorithms, and to ensure the quality of the results, it is necessary to validate the data by different instruments and/or methods. Even though satellite measurements have a wide coverage area, they need to be more accurate, since the incorporated data acquisition and processing algorithms still lack precision. For this reason ground-based measurements are necessary for calibration purposes.  In this study a methodology was used to validate the Lidar Ratio from CALIOP, by obtaining the aerosol optical depth data from 2007-2016 of a sun photometer part of the AERONET network and installed in Petrolina-PE in the Brazilian Northeast. The CALIOP data were obtained using 54 coincident measurements under cloud-free conditions which corresponds to 31%of all existing measurements in the proximity of Petrolina/PE from 2007-2016. An AERONET/CALIPSO model (A/C-Model) developed by Lopes et al. (2003) was used, which defined the new Lidar Ratio, for comparison with the values of the CALIOP HERA algorithm. The performance of the A/C-Model for the characterization of the different aerosol types in the study area registered high frequency occurrences of clean marine aerosol (25 to 30 sr) and smoke (70 sr),  whereas CALIOP registered high frequencies of a mixture of dust with pollution aerosol (55 sr to 60 sr), and biomass burning or polluted continental aerosol (70 sr). The results of the A/C model were compared to CALIOP, which showed that the global model indicated a superestimation of the Lidar Ratio. We assume that the global model may not be adequate for the region. A super estimation may be associated to the CALIOP calibration, especially due to the influence of the South Atlantic Anomaly of the Earth’s magnetic field that may affect the accuracy of the system’s measurements.

MEMBROS DA BANCA:
Presidente - 1879213 - JUDITH JOHANNA HOELZEMANN
Interno - 1752417 - CLAUDIO MOISES SANTOS E SILVA
Interno - 157.613.028-29 - MARIA PAULETE PEREIRA MARTINS - INPE
Externo à Instituição - CRISTINA TOBLER DE SOUSA RAE - UFRN
Externo à Instituição - FÁBIO JULIANO DA SILVA LOPES - IPEN