Banca de DEFESA: ANDERSON LUIZ PINHEIRO DE OLIVEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ANDERSON LUIZ PINHEIRO DE OLIVEIRA
DATA : 20/12/2016
HORA: 10:00
LOCAL: AUDITÓRIO DO DEPARTAMENTO DE GEOFÍSICA
TÍTULO:

GRAVITY WAVE STUDY IN THE EQUATORIAL STRATOSPHERE OVER THE SOUTH AMERICAN SECTOR OF LATITUDES

PALAVRAS-CHAVES:

Gravity waves, Equatorial Stratosphere, Weather balloons, Temperature profile, Brunt-Väisälä frequency.

PÁGINAS: 110
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Geofísica
ESPECIALIDADE: Aeronomia
RESUMO:

Atmospheric disturbances generated by gravity waves exhibiting quasi-periodic characteristics have been intensively studied in recent decades. However, only a few of these studies refers to equatorial atmosphere above the South American sector latitudes. In this work we discuss results concerning the study of gravity waves signatures in the temperature profile of the equatorial stratosphere, in a height range of 16 – 30 km from radiosonde installed in weather balloons routinely launched by the Meteorological Station located in Launching Center of Barreira do Inferno (CLBI), in the metropolitan region of Natal/RN, (5.8°S; 35.5°W), during the year 2000. The objective of this research was to study the characteristics of the disturbances, the temperature profile of the stratosphere, which could be attributed to passing gravity waves that layer. Thus, the data obtained by radiosonde were compared with the theoretical data generated from the MSIS-90 semi-empirical model and, therefore, from the Fast Fourier Transform (FFT) was possible to determine the angular frequency of disturbance and comparable them with the fundamental frequency of oscillation of the neutral atmosphere, or the Brunt-Väisälä frequency. In addition, the density profile of potential energy was calculated and the results were compared of the classical theory of linear gravity waves, it is estimated that the overall energy associated to wave whose dissipation occurs in the average atmosphere. During the study period, the year 2000, the CLBI Meteorological Station held a total of 185 daytime surveys, all around 12 hours (UT). After analysis of these surveys were detected 29 cases in which it was observed almost periodic disturbances with periods, angular frequency and vertical wavelengths compatible with gravity waves. The periods have found in the range 5.7 – 26.0 minutes, vertical wavelengths was in the range of 1.0 – 3.0 km, the angular frequencies of the order of 10-3 rad/s and associated energy density to order waves was in the range 0.5 to 9.0 J/kg.

MEMBROS DA BANCA:
Externo à Instituição - CARLOS ALEXANDRE BARROS DE ALMEIDA - IFRN
Interno - 1858120 - DAVID MENDES
Presidente - 348011 - GILVAN LUIZ BORBA
Interno - 1346630 - LARA DE MELO BARBOSA ANDRADE
Externo à Instituição - RAFAEL CASTELO GUEDES MARTINS - UFERSA