Global Conveyor Belt

Conveyor Belt Circulation

• Diagnose conveyor belt pathways– Mass, volume, heat & salt budgets (inverse analysis)

• Water mass analysis

– T, S, O2 & Nuts provide water mass pathways

• NADW production

– Where, how & change over time

• Transient tracers

–water mass pathways & age since ventilation

Global Conveyor Belt

Global Circulation

Global Heat Transport

Global Heat Transport

Water Mass Analyses

Water Mass Analyses

Global Surface Water Masses

Deep Water Masses

Locations of Deep Water Production

WOCE A16 Line

Atlantic Circulation

Atlantic Circulation

Global Conveyor Belt

Global Conveyor Belt

NADW

AAIW

AABW

Med

Global Conveyor Belt

Global Conveyor Belt

Global Conveyor Belt

Tracing Out AA Water Masses

Following AAIW

Atlantic Circulation

North Atlantic Currents

NADW Production

Working in the Labrador Sea

Global Conveyor Belt

NADW Production

NADW Simulatio

nOGCM simulation of NADW dispersal

1/4o eddy permitting

300 year experiment

Tracer is release in North Atlantic

Followed in time

NADW Simulatio

nOGCM simulation of NADW dispersal

Model tracer @ depth of max NADW outflow

100 y

300 y

1000 y

Mankind to the rescue!!!

Transient Tracers

A22 CFC-12 Concentrations

STMW

GS

DeepCaribbean

AAIW

High CFC’s – recently ventilated waters

Low CFC’s – old water

NAD

W

Transient Tracers

Pacific P16 CFC-12

AAIW

AABWVery Old Water

CFC’s as Transient Tracers

Mixing with ocean imprints ventilated waters w/ CFC levels

Provides a ventilation “age” for water mass

Atmospheric CFC’s are now dropping

Good for the O3 hole

Bad for tracer work…

A22 CFC-12 Concentrations

STMW

GS

DeepCaribbean

AAIW

High CFC’s – recently ventilated waters

Low CFC’s – old water

NAD

W

Atlantic A22 CFC-12 Age

Age calculations by Bill Smethie & Samar Khatiwala [LDEO]

STMW

DeepCaribbean

AAIW

NAD

W

Transient Tracer Age

Ocean & atmosphere CFC concentrations are used to determine a pCFC age

Takes into account exchanges of CFC at sea surface

Lots of assumptions…

Labrador Sea Water age

Transient Tracers

OGCM simulation of atmos CFC dispersal

1/4o eddy permitting

120 year experiment

Tracer is exchanged by sea surface

Followed in time

Anthropogenic CO2

Anthropogenic CO2

CFCs & CO2 observations are used to estimate anthropogenic CO2

Globally 118 +/- 19 Pg C

Nearly ½ of all fossil fuel CO2 are in oceans

Sabine et al. [2005]

Anthropogenic CO2

Another Conveyor Belt

QuickTime™ and a decompressor

are needed to see this picture.

Meridional Overturning Circulation

QuickTime™ and a decompressor

are needed to see this picture.

Overturning circulation in Sverdrups

Is Overturning Slowing?

Is Overturning Slowing?

• Stronger southward transport in upper ocean• Decrease in NADW flow south

NADW

Is Overturning Slowing?

Global Conveyor Belt

Conveyor Belt Circulation

• Diagnose conveyor belt pathways– Mass, volume, heat & salt budgets (inverse analysis)

• Water mass analysis

– T, S, O2 & Nuts provide water mass pathways

• NADW production

– Where, how & change over time

• Transient tracers

–water mass pathways & age since ventilation