Date post: | 21-Dec-2015 |
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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
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
A22 CFC-12 Concentrations
STMW
GS
DeepCaribbean
AAIW
High CFC’s – recently ventilated waters
Low CFC’s – old water
NAD
W
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
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]
Meridional Overturning Circulation
QuickTime™ and a decompressor
are needed to see this picture.
Overturning circulation in Sverdrups
Is Overturning Slowing?
• Stronger southward transport in upper ocean• Decrease in NADW flow south
NADW