The Effect of Peaks in the Solar Decadal Oscillation on Atmosphere and Ocean in the Pacific Region (Note: Change of title)
Harry van Loon, NCAR
During 14 peaks in the Decadal Solar Oscillation since 1860 the mean reponse of the atmosphere and ocean in the Pacific region during northern winter to the solar forcing was as follows: The process took place as a strengthening and meridional displacement of the Intertropical Convergence Zone in the Northern Hemisphere and of the South Pacific Convergence Zone, with increased rainfall in these Zones and strengthening of the SE-trades. Consequently upwelling of cooler water in the equatorial belt increased and the dry zone strengthened and extended westwards. The Hadley circulation weakened and the Walker circulation strengthened; and associated positive sea-level pressure anomalies were found in the Gulf of Alaska. The process appears as an enhancement of the climatological mean, has traits in common with Cold Events in the Southern Oscillation, but is far from as pronounced. It is the preferred response to solar forcing at its decadal peaks. In all other years the region is not constrained by a strong solar influence, and the circulation can then vary from Warm to Cold Events in the Southern Oscillation. The accompanying signal in the stratosphere is discussed.
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