We present analyses of large-scale sea-level variations at seasonal and interannual timescales in three different oceans, using a combination of TOPEX/POSEIDON (T/P) data, satellite SSTs, and OGCMs. In the Indian Ocean, propagating semi-annual Rossby waves from 20-30°S are evident in both the T/P sea level anomalies and SSTs, and are important in carrying the large interannual variations from the eastern boundary into the ocean interior. In the Atlantic, surface heat fluxes have been inverted

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... om T/P data via an OGCM, and could be used to improve those derived from meteorological models. Finally, in the Pacific, vertical baroclinic modes derived from an OGCM are used to estimate the first three baroclinic contributions to T/P sea level. Rossby wave propagation in the south Indian Ocean We have been investigating the southeast Indian Ocean boundary as a generation region for many westward propagating signals. Annual Rossby waves around 10°S are well documented, but there is also a broad range of westward propagating signals between 20-35°S with periods between 100-180 days, and spatial scales of around 500 km [Morrow and Birol, 1997]. These mesoscale features appear to originate at the eastern boundary, where instabilities in the density-driven coastal current generate a large amount of variability, in the form of meanders and separating eddies. Whether these propagating features are generated by local or remote wind-forcing, or local separation of eddies is currently under investigation. Figure 1 shows that these westward propagating signals have distinct signatures in both dynamic height (measured from altimetry) and SST (from AVHRR). In particular, interannual variations at the eastern Indian boundary can be carried to the ocean interior. For example, altimetry and XBTs show a large warming event on the eastern Indian boundary around May, 1994, which propagates offshore. During the following summer the additional steric effect leads to a large-scale anomalous SST warming in the ocean interior around 90-110°E, lasting several months.