HR: 10:20h
AN: U32A-01 INVITED     [Abstracts]
TI: How does Atlantic climate change affect the eastern Pacific: Coupled modeling and paleoclimate implications
AU: * Xie, S
EM: xie@hawaii.edu
AF: IPRC, University of Hawaii, United States
AU: Timmermann, A
EM: axel@hawaii.edu
AF: IPRC, University of Hawaii, United States
AU: Okumura, Y
EM: yukoo@ucar.edu
AF: CGD, NCAR, United States
AU: Miyama, T
EM: tmiyama@jamstec.go.jp
AF: FRCGC, JAMSTEC, United States
AB: Paleoclimate observations suggest coherent variability in various parts of the globe in step with the Dansgaard- Oeschger cycles, which are often associated with Heinrich events of massive land ice sheet discharges into the North Atlantic. Recent water-hosing experiments with coupled GCMs show that a shutdown of the Atlantic meridional overturning circulation induces large ocean-atmospheric anomalies not only in the Atlantic but in the Pacific as well. In particular, the intensified cross-Central American winds have been identified as a key conduit for the tropical Pacific response. Central America features narrow mountain ranges with three major gaps: Tehuantepec, Papagayo, and Panama. The IPRC regional ocean-atmosphere model (iROAM), consisting of a regional atmospheric model (RAM) and a Pacific Ocean basin model, is used to study the conduit mechanisms of narrow Central American Isthmus. The RAM extends from the central Pacific to the western Atlantic, from 35S to 35N. The 0.5 deg resolution is a significant improvement over global coupled GCMs in representing Central American mountains. In response to the North Atlantic cooling, the SST annual cycle weakens on the equator, triggered by an intensified Panama wind jet. The tropical eastern Pacific response is highly seasonal, with a major cooling during the February-April season but much weaker SST anomalies in other seasons. The ocean-atmospheric processes leading to this strong seasonality, and the cause of consistency and diversity among different GCM water-hosing experiments will be discussed in detail in the presentation.
UR: http:iprc.soest.hawaii.edu/~xie
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 4901 Abrupt/rapid climate change (1605)
SC: Union [U]
MN: 2007 Joint Assembly