12C.1
The Nature of the Indian Ocean Zonal Mode
Galina Chirokova, University of Colorado, Boulder, CO; and P. J. Webster, C. Clark, and W. Han
We portray the Indian Ocean Zonal Mode (IOZM or Indian Ocean Dipole) as a coupled ocean atmosphere instability of the Indian Ocean occurring often in conjunction with extremes of ENSO but also independently. By examination of data and the results of numerical models of the atmosphere and the ocean, we show that the IOZM has many characteristics of the a lagged-oscillator and made up of atmospheric forced ocean waves. The IOZM is shown to be strongly tied to the annual cycle and, depending on the phase, a result of anomalously strong or weak monsoons. The IOZM is shown to possess a identifiable canonical life cycle. The life-cycle is sufficiently robust to allow the foreshadowing of excessive rainfall or drought in East Africa during the autumnal equinox, or anomalous sea-level heights in the Bay of Bengal.
Session 12C, Ocean-Atmosphere Interaction I (Parallel with Sessions 12A, 12B, and 12D)
Thursday, 2 May 2002, 9:00 AM-10:30 AM
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