Propagation and Decay of Forced and Free Baroclinic Rossby….pdfVIP

NOVEMBER 1997 Q I U E T A L . 2405 Propagation and Decay of Forced and Free Baroclinic Rossby Waves in Off-Equatorial Oceans* ¨ BO QIU, WEIFENG MIAO, AND PETER MULLER Department of Oceanography, University of Hawaii at Manoa, Honolulu, Hawaii (Manuscript received 22 January 1997, in final form 16 April 1997) ABSTRACT Baroclinic Rossby wave motions in the off-equatorial oceans are investigated with emphasis on how eddy dissipation can influence the propagation of the height anomalies when both the forced wave response to wind in the interior ocean and the free wave response originating along the ocean’s coastal and topographic boundaries are present. By explicitly estimating the decay scale for the long baroclinic Rossby wave, the authors show that the forced wave patterns at all off-equatorial regions appear to propagate westward at 2c , where c is the phase r r speed of the long baroclinic wave. The presence of the boundary-generated, free Rossby waves in the low latitudes, however, reinforces the 1cr phase propagation in the combined height anomaly fields. Toward higher latitudes, this reinforcement weakens as the boundary-generated, free waves become highly dissipative; as a result, the