11.6
On the North Atlantic decadal variability
Lixin Wu, University of Wisconsin, Madison, WI; and Z. Liu
Decadal variability in the North Atlantic is studied in a series of global coupled ocean-atmosphere model simulations aided by a modeling surgery approach. Both observations and the model show the North Atlantic exhibits two distinctive modes: an interannual to decadal tripole mode and a decadal to multidecadal basin-scale monopole mode. Our modeling surgery study found that the tripole mode originates predominantly from atmospheric internal variability known as the North Atlantic Oscillation with no need to invoke ocean-atmosphere coupling. In contrast, the decadal variability of the monopole depends critically on ocean-atmosphere coupling. The transition from the monopole to the tripole tends to be associated with the mean oceanic circulation. Analogy to the North Pacific decadal variability is then discussed.
Session 11, Observed Seasonal/Interannual Variability (Room 608)
Thursday, 15 January 2004, 11:00 AM-3:00 PM, Room 608
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