Tropical Pacific-driven decadel energy transport variability

Publication Type  Journal Article
Year of Publication  2005
Authors  Hazeleger, W.; Severijns, C.; Seager, R.; Molteni, F.
Journal Title  Journal of Climate
Volume  18
Issue  12
Pages  2037-2051
Journal Date  Jun 15
ISBN Number  0894-8755
Accession Number  ISI:000230199600012
Key Words  ocean circulation; heat-transport; storm track; el-nino; climate; atmosphere; enso; teleconnections; thermocline; oscillation
Abstract  

The atmospheric energy transport variability associated with decadal sea surface temperature variability in the tropical Pacific is studied using an atmospheric primitive equation model coupled to a slab mixed layer. The decadal variability is prescribed as an anomalous surface heat flux that represents the reduced ocean heat transport in the tropical Pacific when it is anomalously warm. The atmospheric energy transport increases and compensates for the reduced ocean heat transport. Increased transport by the mean meridional overturning (i.e., the strengthening of the Hadley cells) causes increased poleward energy transport. The subtropical jets increase in strength and shift equatorward, and in the midlatitudes the transients are affected. NCEP-NCAR reanalysis data show that the warming of the tropical Pacific in the 1980s compared to the early 1970s seems to have caused very similar changes in atmospheric energy transport indicating that these atmospheric transport variations were driven from the tropical Pacific. To study the implication of these changes for the coupled climate system an ocean model is driven with winds obtained from the atmosphere model. The poleward ocean heat transport increased when simulated wind anomalies associated with decadal tropical Pacific variability were used, showing a negative feedback between decadal variations in the mean meridional circulation in the atmosphere and in the Pacific Ocean. The Hadley cells and subtropical cells act to stabilize each other on the decadal time scale.

Notes  

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