Banca de DEFESA: MARIA RAYLA DOS SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIA RAYLA DOS SANTOS
DATE: 28/02/2020
TIME: 09:00
LOCAL: Auditório CCET
TITLE:

SURFACE OCEANIC WAVES FROM SEISMIC NOISE IN THE EAST COAST OF NORTHEAST BRAZIL

KEY WORDS:

Microsseism. Surface oceanic gravity waves. PNBOIA. Coastal variability.

PAGES: 69
BIG AREA: Ciências Exatas e da Terra
AREA: Oceanografia
SUBÁREA: Oceanografia Física
SPECIALTY: Interação do Oceano com a Atmosfera
SUMMARY:

The study of ocean waves spread and dissipation is of extreme importance for the safety and efficiency to the offshore engineering works, as well as for the coastline management. However, there are difficulties associated with obtaining measured data at sea that make a good time-space sampling difficult to obtain. An alternative to filling these voids in the observations comes from the production of ocean waves data indirectly through the geophysical effect registered by means of the microseisms. The frequencies of the signals which are of interest of this proposition at frequencies lower than 1 Hz (períodos > 1 s). In this context, this research aims to evaluate the association of the oceanic gravity waves parameters and the microseismic signals recorded in the northeastern Brazilian coast. The oceanographic data come from the Recife buoy, which is the only one of the Programa Nacional de Boias (PNBOIA) located on the eastern part of the northeast Brazilian coast, from June 11 to November 16, 2015, in addition to WAVEWATCH III output, when required. The meteorological data come from reanalysis ERA5 and images of the infrared channel from GOES 13 and METEOSAT-10 satellites. The seismological data come from the NBRF station, installed in Rio Formoso – PE (closest station to the oceanic buoy). From the analysis of gravity wave characteristics, it was observed that H_s has a median of 1.99 m in winter and 1.53 in spring, predominantly from the southeast, with a median T_p of 8.3 s. From the investigation of the main oceanic events it was found that the largest H_s are related to advance of cold fronts that intensified the winds at the ASAS extremities and the southeastern trade wind, along with small trough near the east coast of the Northeast. The pre-processing and spectrograms of the seismograms revealed that for the work area the microsisms are in the range 0.04 - 0.12 Hz (8 - 25 s) for primary microseism and at 0.12 - 0.70 Hz (1 - 8 s) for secondary microseism. The amplitudes of secondary microseism, from 0.7 * (1e-7) nanometers, showed a linear behavior with the variation of H_s which allowed the estimation of a transfer equation given by . So the efficiency of the use of microseism for the oceanographic and, consequently, meteorological study was demonstrated.

BANKING MEMBERS:
Presidente - 1164414 - WEBER ANDRADE GONCALVES
Interno - 1858120 - DAVID MENDES
Externo ao Programa - 1451214 - ADERSON FARIAS DO NASCIMENTO
Externo ao Programa - 2276514 - MARCIO MACHADO CINTRA
Externo à Instituição - MARCUS ANDRÉ SILVA - UFPE