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7 th Annual Summer Institute and Friday Harbor Laboratory Centennial Symposium How Does Ocean Circulation Matter for Climate Change? Sept. 14-17, 2008 Friday Harbor Laboratories, San Juan Island, WA. - PowerPoint PPT Presentation
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7th Annual Summer Institute
and
Friday Harbor Laboratory Centennial Symposium
How Does Ocean Circulation Matter for Climate Change?
Sept. 14-17, 2008
Friday Harbor Laboratories, San Juan Island, WA
The thermohaline circulation is sometimes called the ocean conveyor belt, the great ocean conveyor, or the global conveyor belt. On occasion, it is mistaken to mean the meridional overturning circulation (often abbreviated as MOC), but is distinct from it in two ways. Firstly, the MOC only occurs around the meridian - hence the name - and so is confined to the Atlantic Ocean. Secondly, there is published data on the MOC's existence, whilst the thermohaline circulation remains a purely theoretical conjecture.Wickipedia (Updated September 2, 2008)
•Volume integrate the fraction of AABW at each location
•Logarithmic Scale
•NADW 21% of the global ocean volume
•AABW 36% of the global ocean volume
•AABW has at least 1.7 times the volume of NADW
AABW and NADW Volumes (Johnson 2008)
NADW
AABW
Warming is apparent in the southern ocean
The Indian Ocean
SE Indian Ocean1994/5 & 2007
Johnson, Purkey, & Bullister (in press)
13-year time interval 2007- 1994/5
0.1C abyssal warming=0.9W/m2
4cm Sea level rise
Isolated to southern basins
The Pacific Ocean
MOC Active in Pacific, but shallow. Ocean drives fluxes to the atmosphere in the western
boundary current
MOC and Salinity
Coupled model
Ocean Only Model
Thompson and Cheng 2008
Sea Surface Height Variability and Mean Path of Kuroshio
AltimeterObservations
10 km model
Upper Ocean Heat BudgetFrom a High Resolution Ocean Model
Advection dominates (as in observationally derived budget) (Kelly et al, 2007)
Heat storage rate = surface flux + lateral flux + isotherm motion
The Atlantic Ocean
Connection between the mid and high latitudes is complex, and
linked to the atmosphere
Steve Yeager, NCAR
Stream Function
T anomaly
No ice Ice
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Mike McCartney, WHOI
Winter 850mb Storm Track
Winter Stability of boundary layer
Winter Surface Storm Track
Booth et al, 2008
Minobe et al, Nature, 2008 (picture from the New Scientist, March, 2008)
Influence of the Gulf Stream on the troposphere
Questions from PCC discussion, August 2008
• What is the definition of the MOC? THC? Can we separate the THC and wind-driven circulation?
• How should models be used to investigate ocean circulation and its impact on climate in the past and in the future?
• How fast does the circulation adjust in the deep ocean, and how fast do the deep tracers change?
• How well do we understand paleo-circulation? Are there limits to our knowledge?
More Questions:
• What is the relative importance of tropical and mid-latitude SST variability for mid-latitude climate?
• Are ocean heat transport anomalies compensated by atmospheric heat transport anomalies?
• Can internal processes alone generate atmospheric variability?
• What background state in the atmosphere favors influence of mid-latitudes SST on the atmosphere?
• What part of the high latitudes is important to climate? South of 40S? North of 60N? Is sea-ice the key?
Schedule
• Breakfast 7:45-8:15 Monday-Wednesday
• Morning Session 8:45-12:30
• Lunch 12:30-1
• Afternoons Free
• Dinner 6-6:30
• Evening Session 7-10:30
• Monday MorningThe Ocean in the Climate System
• Monday EveningOcean Circulation in the PastPanel Discussion--Can the Ocean Circulation Change Drastically as Implied by
Paleo Data?• Tuesday Morning
Variability of Ocean Circulation, Interannual to Decadal• Tuesday Evening
The Carbon cycle, and land/ice interactions: what is the role for the oceans in future and past climate change?
Panel Discussion--What can we say confidently? What is a reasonable best guess about the role of the ocean in future climate change?
• Wednesday MorningDebate: What can models tell us about ocean circulation and climate? Summary Presentation
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