Trouble shooting of anemometers in the TRITON buoy system

The TRITON buoy system, which monitors surface meteorology and vertical profiles of seawater temperature and salinity, consists of unmanned mooring array in the tropical West Pacific and eastern Indian Oceans. The observational data obtained through the system is used both for local fishery, operational monthly weather forecasts, and climatic research as to predict El Nino-Southern Oscillation (ENSO) events. In the system, analogue signals from anemometers are electronically converted into digital in a 3-minute-on and 7-minute-off cycle before satellite transmission. However, no data (error massage) were transmitted from some buoys for the night at the running test in Japan. The duration of such phenomena varied among the buoys. Buoys, which started to emit no data earlier at night, always started to emit normal data again later in the morning. Our inspections clarified that these phenomena were attributed to decrease of capacity of noise fitter condensor at low temperatures. The capacity decrease caused voltage insufficiency of DC source while rush current occured. We improved the data processing circuit board. In addition, we started to develop a new base.