HR: 08:00h
AN: PP21A-01 INVITED     [PDF]
TI: On the Location of the ITCZ
AU: * Philander, G S
EM: gphlder@splash.princeton.edu
AB: To arrive at a coherent and consistent picture of climatic conditions at a certain time in the past, information concerning the location of the ITCZ at that time needs to be complemented with additional information concerning parameters such as the intensity of equatorial upwelling, the depth of the thermocline and the period of El Nino. The integration of such diverse observations requires theoretical studies that explore why, over the tropical Pacific Ocean today, the location of the ITCZ and the associated surface wind patterns depend mainly on sea surface temperature (SST) patterns, which in turn depend on the winds. This result implies that ocean-atmosphere interactions amount to positive feedbacks. These feedbacks, unlike those involved in El Nino, are antisymmetrical about the equator and displace the ITCZ poleward. Their intensity decreases as the depth of the thermocline increases. These theoretical results imply that if, at a certain time in the past, the ITCZ was in a northerly position, then there should also be evidence of a shallow thermocline, low surface temperatures and increased upwelling near the equator, and a decrease in the period of El Nino. The possible reasons for inconsistencies between observations and theory (at the time of the Last Glacial maximum for example) will be discussed.
DE: 4267 Paleoceanography
DE: 4522 El Ni¤o
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting