HR: 10:55h
AN: OS11B-03 INVITED     [PDF]
TI: AO/NAO Patterns in the North Atlantic - Arctic Ocean?
AU: * Bond, G C
EM: gcb@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, Rt. 9w, Palisades, NY 10964 United States
AB: There is little question that on annual to possibly decadal time scales, the AO/NAO has an important influence on climate of the Arctic Ocean and northern North Atlantic; however, it has been widely debated whether the same is true on much longer time scales of multi-centuries to millennia. Some authors claiming NAO dipole or tripole patterns on those time scales in the northern North Atlantic have refuted those claims in later publications. Adding to the problem is the possibility that reduction in thermohaline overturning, local buildup of sea ice, or response to solar variations might produce patterns similar to those of the NAO. Certainly, it is far from clear how a pattern resulting purely from atmospheric forcing can be maintained on long time scales. A compilation of temperature-related records spanning most or all of the Holocene together with new data from cores our group has analyzed does not appear to produce geographic patterns of temperature change that are consistent with the AO/NAO. Those records extend from the Laptev Sea to about 40 degrees N in the North Atlantic and are, with the exception of the Laptev Sea, from the open ocean. The sense of temperature change appears to be the same at all of the coring sites; that is, there is no evidence of multipole patterns. Records from the Labrador Sea and from near-shore areas off the Scotian margin, however, exhibit more complicated patterns, but still not those expected from the AO/NAO. In those more restricted areas, the complicated patterns may reflect local climate dynamics and/or the influence of sea ice cover on near surface ocean temperatures.
DE: 1610 Atmosphere (0315, 0325)
DE: 1620 Climate dynamics (3309)
DE: 1635 Oceans (4203)
DE: 3344 Paleoclimatology
DE: 4207 Arctic and Antarctic oceanography
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting