Next Generation Ocean Observing Systems: Part 2, Sensors/Data System/Sampling

Oceanography is an observational science driven by data collected from ships, moorings, satellites, AUVs, etc. Oceanographers are now beginning to contribute to global scale climate change studies, which requires distributing data to others in near-real time. With the new technology developments in satellites and AUV remote sensing, there is still a need for continuous, long-term time-series observations from moored platforms in support of climate change research, weather forecasting and prediction programs, environmental monitoring and assimilative modeling efforts in near real-time. To accomplish this, improved buoys and mooring technologies need to be utilized, new sensors and data systems with intelligent sampling and processing capability need to be incorporated, and world-wide, two-way, high-speed satellite telmetry systems need to be developed to return the data in near-real time to the resesarch and modeling efforts, and allow control of the remote platform from shore.

A moored or freely drifting ocean observing platform requires sensors and a data system to provide environmental information for process, monitoring and assimilative modeling efforts/studies. Most of the forcing and water property changes occur at the air-sea interface. Meteorology sensors allow the forcing to be monitored. Successful measurements have been made on Georges Bank of winds (vector averaged components, speed and gust), air temperature, relative humidity, long and short wave radiation and PAR (photosynthetically active radiation). This allows momentum flux and latent and sensible heat flux studies to be conducted. A vertical array of temperature and conductivity (salinity) sensors in the water column monitor water property changes due to surface flux and advective effects. Water velocity is profiled with acoustic Doppler current profilers to study water property and biota transport. Bottom pressure provides tidal and weather forced sea surface elevation and some wave statistics to be collected. With newer sensors measuring bio-optical properties (optical transmission and backscattering, chlorophyll-a fluorescence, photosynthetically active radiation, spectral absorption and attenuation, and spectral radiance and irradiance) help couple the physical observations with biological studies, and ocean color satellite investigations.

Computer based data systems with increased sampling, processing and storage capability, coupled with greater telemetry capability, are allowing long term studies to be conducted which sample both the short term and long term variability. Burst sampling, conditional sampling, and user requested sampling schemes are all very realistic. PC based systems running DOS and LINUX are being routinely deployed which can utilize/control higher speed telemetry links. Two-way telemetry systems are starting to be used for near-real time return of data to databases on the World Wide Web. They also allow the user some control of the remote instrumentation. The data system can also apply realistic data compression schemes to take advantage of telemetry link capability as well as optimize on-board data storage capability. The end result is more data, more timely data, and better data in support of scientific, monitoring and modeling efforts.