Banca de QUALIFICAÇÃO: ÚRSULA MARTIN DAMASCENO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : ÚRSULA MARTIN DAMASCENO
DATA : 16/06/2019
HORA: 08:00
LOCAL: Sala 1 do PPGG
TÍTULO:

The role of the northeastern Brazilian margin physiography on the western boundary currents, local vortices and jets formation

PALAVRAS-CHAVES:

Continental slope; Equatorial margin; western boundary current; vortices

PÁGINAS: 27
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

Western boundary currents (WBCs) affect the global ocean circulation, climate, and produce localized impact along with their interactions with low latitude edges of ocean basins. This study analyses the response of WBCs over the interactions with the corn of South America Margin, particularly in the North and East sectors of Rio Grande do Norte (RN) on northeastern Brazil, based upon the geomorphological bathymetric characterization of the margin, in situ currents measurements, and ocean currents simulation using the ROMS model. The RN margin provides a critical pathway to the WBCs over the East and North sectors which are narrow and retracted shelf (up to 40 km offshore), and steep upper continental slopes (1:11), separated by a considerable wider (up to 80 km offshore) and shallower shelf (Touros High). To analyze this interaction, a simulation of currents of a period of 11 years was created based on a model ROMS already validated in the literature. This simulation revealed a region of current recirculation in the months of February and August on the Northeastern platform. The margin adjacent to the shade region ranges from 28 km to 38 km, with a depth of approximately 136 m, and a topographic gradient between 7º and 13.5º. The vortices in surface waters (depths of 20 m) in the month of February have diameters of approximately 50 km and 20 km. And in August there were meanders with an approximate extension of 120 km. In addition, it was possible to observe the Northern Undercurrent of Brazil (NBUC) in the numerical models referring to both periods (February and August) at a depth of 70 m.  Current retroflexions occur in this same region of recirculation. In the month of February, this return was more intense with an average velocity of 30 cm.s-¹. In August, the current in this area was almost stationary, with an average speed of less than 10 cm.s-¹.The results revealed that this margin physiography creates a large “shadow” area for the western boundary current at the north margin and provides the formation of vortices and meanders, which affects the sedimentary and ecological system on Brazilian Equatorial continental shelves.

MEMBROS DA BANCA:
Externo ao Programa - 1858120 - DAVID MENDES
Interna - 2218779 - HELENICE VITAL
Externo ao Programa - 2276514 - MARCIO MACHADO CINTRA
Presidente - 2042405 - MOAB PRAXEDES GOMES