A New, Autonomous, Current, Temperature and Salinity Profiler for Storm Conditions

The commercial development and initial deployments of the EM-APEX, a new instrument that is capable of measuring repeated profiles of ocean velocity, temperature, and salinity during hurricanes and severe storms, is proposed. Our understanding of oceanand atmosphere dynamics during severe storms is handicapped, in part, by a lack of instruments and deployment techniques suitable for this severe environment. The EM-APEX represents a union of two mature technologies. The vertical variations ofhorizontal velocity of seawater is determined by the measurement of electric currents induced in seawater as the instrument moves through the earth's magnetic field. These observations of the horizontal electric field (HEF) in the ocean have beensuccessfully used in a wide variety of situations, including high wind and sea conditions. We propose to integrate this proven sensor EM technology with a mature autonomous ocean profiling instrument, the APEX (Autonomous Profiling Explorer), of whichover 2000 units have been built and deployed. APEX is certified by US DOD for deployment from C130 aircraft, and has been deployed by this method in the Atlantic Ocean, Red Sea, Japan, Mediterranean, and South China Seas.The new velocity and water property profiling floats will be deployed in 2004 hurricanes chosen by the ONR CBLAST program. They will be programmed to continuously profile from their parking depth, say 200 m to the surface. Each profile will require abouthalf an hour to traverse 200 m, more if a deeper parking depth is chosen. The floats will be deployed in a 2004 hurricane along with other CBLAST floats and assets. Improved understanding of storm dynamics will benefit storm forecasters, naval and commercial ship operations, coastal communities and the insurance and offshore petroleum industry. This work will assure that this technology is available to the Navy andworldwide users. There is the expectation that many of these velocity profiling floats will be used in the international ARGO float program. The results should be improved weather prediction, storm detection, SML evolution, and basic research.