Banca de DEFESA: GUSTAVO LAUTON DE OLIVEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : GUSTAVO LAUTON DE OLIVEIRA
DATA : 07/02/2019
HORA: 09:00
LOCAL: IGEO
TÍTULO:

 

OBSERVATIONS OF BREAKING NONLINEAR BAROCLINIC TIDES ON THE AUSTRALIAN NORTH WEST SHELF EDGE DURING WINTER STRATIFICATION

PALAVRAS-CHAVES:

 

internal tides; tidal bores; solitary waves; solitons; turbulent boluses; wave breaking.

PÁGINAS: 74
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Oceanografia
SUBÁREA: Oceanografia Física
ESPECIALIDADE: Movimento da Água do Mar
RESUMO:

A comprehensive observational data set was used to examine the shoaling and breaking characteristics of shoreward propagating nonlinear internal tides on the edge of the Australian North West Shelf (NWS) during the late winter of 2013. The internal wave events supported the grouping of field observations into two distinct categories: (1) prior-; and, (2) post- wave breaking. It was found that the transition from (1) to (2) was marked by the rise of nonlinear steepening () and reduction in dispersion (), both coefficients that parameterize nonlinear wave effects on the Korteweg-de Vries (KdV) equation. We developed a criterion for wave breaking from the dimensionless parameter that relates these two terms: where wave breaking occurs when In the first group, the rear of the internal tide was initially composed of a series of internal solitary waves (ISWs) of depression, these high-frequency waveforms were apparently merged into the rear face of a longer wave, which steepened and formed a shoaling bore while decreases. In the second, as dropped below the unit, the wave broke and formed multiple turbulent boluses at the rear. The kinematics of the wave field, taken together with a number of empirical parameters adapted from numerical solutions for ISWs of depression, suggested that these turbulent features have resulted from collapsing-plunging breakers and that the boluses have developed trapped cores. Therefore, explaining strong events of diapycnal mixing and onshore transport of water and material observed during late winter. Nothing similar has ever been described during summer months for the region, thus opposing preconceived suggestions that the nonlinear internal wave field is of secondary importance on the NWS in winter. Additionally, we have proposed the adjustment of the breaking location criterion to long internal tides, which produced a prognostic that was confirmed empirically through glider’s profiles.

MEMBROS DA BANCA:
Interno - 1562309 - CARLOS ALESSANDRE DOMINGOS LENTINI
Interno - 1868627 - JANINI PEREIRA
Externo à Instituição - JOAO ANTONIO LORENZZETTI - INPE