Orbital controls on the El Nino/Southern Oscillation and the tropical climate

Publication Type  Journal Article
Year of Publication  1999
Authors  Clement, A. C.; Seager, R.; Cane, M. A.
Journal Title  Paleoceanography
Volume  14
Issue  4
Pages  441-456
Journal Date  Aug
ISBN Number  0883-8305
Accession Number  ISI:000081564300003
Key Words  sea-surface temperature; last glacial maximum; ocean-atmosphere interactions; equatorial pacific-ocean; southern oscillation; seasonal cycle; hadley circulation; thermocline depth; nino; enso

The global synchroneity of glacial-interglacial events is one of the major problems in understanding the link between Milankovitch forcing and the climate of the late Quaternary. In this study we isolate a part of the climate system, the tropical Pacific, and test its sensitivity to changes in solar forcing associated with changes in the Earth's orbital parameters. We use a simplified coupled ocean-atmosphere model that is run for the past 150,000 years and forced with Milankovitch changes in the solar insolation. This system responds primarily to the presessional cycle in solar forcing and is capable of generating a mean response to the changes in the seasonal distribution of solar radiation even while the annual mean insolation is roughly constant. The mean response to the precessional forcing is due to an interaction between an altered seasonal cycle and the El Nino/Southern Oscillation (ENSO). Changes in the ENSO behavior result in a mean tropical climate change. The hypothesis is advanced that such a change in the tropical climate can generate a globally synchronous climate response to Milankovitch forcing.


218QZTimes Cited:141Cited References Count:87

URL  <Go to ISI>://000081564300003