Scientific Results using a Decade of Data Collected by the PNBOIAProgram in the South Atlantic

Olga T. Sato, Ph.D. Guilherme Campanoolga.sato@usp.br

Oceanographic Institute – University of São Paulo

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Roteiro

1 IntroductionThe ProgramData StatisticsTemperature and Velocity FieldsVariability and Trends

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Introduction

Roteiro

1 IntroductionThe ProgramData StatisticsTemperature and Velocity FieldsVariability and Trends

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Introduction The Program

Programa Nacional de Bóias - PNBOIA

Brazilian National Drifter ProgramActivities since 1997 under theGOOS/Brazil programPart of the Global Drifter ProgramMain goal: To obtain and distributeoceanographic and meteorologicalmeasurements on the Atlanticthrough an array of drifting andmoored buoys;Universities, research institutions,government and private sectors, andthe Navy (responsible for launchingoperations).

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Introduction The Program

Some specifics of the drifters

Surface Velocity Program (SVP) drifterwith a 15 m drogue (holey-sock)Measurements:

1 Water temperature (20-30 cm under thesurface)

2 Position and time velocity at 15 m3 Atmospheric pressure (SVP-B)

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Introduction Data Statistics

Spaghetti Plot - Drifters deployed since 1999

75 drifters predicted tobe deployed in 2010.

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Introduction Data Statistics

Data Distribution (1◦×1◦)

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Introduction Temperature and Velocity Fields

SST measured by the drifters

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Introduction Temperature and Velocity Fields

WOA09 monthly mean SST

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Introduction Temperature and Velocity Fields

SST difference (PNBOIA minus WOA09)

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Introduction Temperature and Velocity Fields

Near–Surface Current Velocity: 1◦×1◦

Hansen and Poulin(1996) scheme tofilter thetemperature andvelocity;

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Introduction Temperature and Velocity Fields

Surface Velocity Field at the SW Corner from Buoys

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Introduction Temperature and Velocity Fields

Surface Velocity Field from Altimeters - AVISO

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Introduction Variability and Trends

Velocity Variability at the SW Corner

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Introduction Variability and Trends

Conclusions 12

Some of the main dynamical features of the Atlantic is captured bythe statistical analysis of the trajectories of the drifters, e.g.,boundary currents, recirculation regions, etc.There are indications of warming and cooling trends in some partsof the South Atlantic as measured by drifters in comparison withclimatology; at the Brazil–Malvinas confluence this evidence isclearer.The analysis of the current velocities measured by the driftersshows an increase of its variability after 2006. This trend iscorroborated with altimeter derived velocities as well.

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Introduction Variability and Trends

goosbrasil.org

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Introduction Variability and Trends

Thank You!

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