Observations of Upper Ocean Hydrography and Currents in the Japan Sea Using PALACE Floats

The long-term goal of this project is to better understand the properties of the upper portion of the water column in the Japan Sea. It is important to understand the seasonal cycle in the upper 1000 meters of the Japan Sea: how the Sea stratifies in spring and summer and how it forms a mixed layer in fall and winter, sometimes with deep convection occurring. I want to be able to study the circulation and hydrography of the upper 1000 meters of the Japan Sea over at least a few complete seasonal cycles so as to understand the process of mixed-layer formation and destruction there. In some ways the Japan Sea behaves as a subtropical ocean, and in other ways it is more like a subarctic one. As a result, it is a useful laboratory for studying many oceanographic processes that occur throughout the world ocean. I plan to deploy about 40 PALACE floats in the western Japan Sea during the summer of 1999. These floats will be deployed from the Russian research vessel Professor Khromov from the FERHRI laboratory in Vladivostok. These floats will cycle between the sea surface and 1000 meters depth at approximately 10 days intervals and will collect profiles of temperature and salinity during their ascent phase on each cycle. In all, about 1500 profiles per year will be collected this way. This will provide good coverage of the Japan Sea, even in the winter season. All of the results will be made available in real-time via the ARGOS system and a web page. Most of the planned deployments will take place inside the Russian EEZ in the Japan Sea. To carry out this work, clearance has been requested from the Russian government, and I have been informed that there is a good chance of approval. The instruments will be deployed by Russian scientists; no U.S. personnel will be allowed to participate in the cruise. Several Russians will visit Seattle in January to be instructed in the use of these instruments.