Third, important progress reports were presented by Drs. Delecluse, Hacker, Shetye, Jensen, Schiller and McCreary. All those somehow recognized the importance of the barrier layer and salinity effects in an ocean-atmosphere coupled system. The warm SST pool in the Indo-Pacific sector enhances precipitation over the region and introduces stable stratification in the surface layer. This reduces the entrainment of subsurface waters and leads to even warmer SST due to solar insolation. The positive feedback of this kind should be paid more attention in modeling studies. Also, the thin barrier layer is responsible for much stronger surface currents and thus for more active advection to redistribute heat and fresh water. In addition, Dr. McCreary demonstrated usefulness of the intermediate ocean model to understand water mass distribution in the Indian Ocean by taking into account precipitation minus evaporation (P-E), river runoffs, IT and saline intermediate water discharge from the Red Sea.
Last but not least are roles of subtropical phenomena and a possible link with the tropical phenomena. Dr. Morrow discussed excitation and propagation of mid-latitude Rossby waves and showed the existence of an interesting semi-annual signal along the west coast of Australia. Although it is not referred to often nowadays, discussed in the early 1980s was the reason why the ENSO signal appears first in the variation of the South Pacific High. To seek for a possible link with subtropical phenomena and even with the Southern Ocean is a challenging direction of a new research to enhance predictability. In this regard, the audience was briefed on a newly discovered subtropical dipole SST mode in the Indian Ocean (Behera and Yamagata, 2000).
In order to enhance measurement of surface fluxes (winds, heat, fresh water) and oceanic & atmospheric variables, we need to support the satellite altimeter/ ocean wind/sea surface salinity measurement missions. Introducing buoys is of urgent need to have operational forecasts at the same level with the counterpart in the Pacific. Since water mass redistribution is particularly important in the unique sector of the world, the ARGO program using the profiling ALACE floats in the Indian Ocean must be strongly endorsed. To strengthen the existing VOS (XBT/XCD) measurement is also a necessary element of the Indian Ocean Observing System. The new technology, AEROSONDE, will be also quite useful.
