Four-dimensional (4-D) Oceanographic Instrumentation

The dissemination of data collected from undersea systems historically has been accomplished via cable and/or by RF telemetry. In many cases the available (limited) signal processing capability has required the transmission of raw or only slightlyprocessed data to the end user. Due to recent major advances in DSP technology, it is now possible to develop systems of sensors with substantial organic computing power which permits in-situ data processing and data fusion. Because of recent majoradvances in undersea wireless acoustic communications, it is possible to deploy networks of such sensor systems covering large ocean areas, from very shallow water to the deepest oceans. We propose to develop the infrastructure to support wireless networks of underwater sensor systems, specifically including chemical sensing, optical imagery, and small sonar systems. Our immediate developments focus on supporting and enhancing thespectrophotometric elemental analysis systems (SEAS) for measurements of a wide variety of substances at nanomolar and subnanomolar concentrations. SEAS measurement capabilities include pH and CO2 partial pressure, ferrous and ferric iron, cupric andcuprous ions, nitrate and nitrite, hydrogen sulfide, chromate, and chlorophyll. Since SEAS analyses involve full spectral measurements in the visible (resolution approximately 3 nanometers), our systems are well suited to measurements of the visible lightattenuation characteristics of ocean water, and measurements of seawater fluorescence spectra. There is a strong interest internationally in monitoring of marine environments for pollution, fisheries management, and smuggling into littoral waters. The developments anticipated from this work will permit us to develop integrated systems to supportsuch monitoring.