| Abstract: An autonomous, moored profiler [the
Oceanic Remote Chemical/Optical Analyzer (ORCA)] was developed to sense
a variety of chemical and optical properties in the upper water column.
It is presently used to monitor water quality parameters in South Puget
Sound—a largely undeveloped area subject to extensive future
urbanization. ORCA has three main components: 1) a three-point moored
Autonomous Temperature Line Acquisition System (ATLAS) toroidal float;
2) a profiling assembly on the float with computer, winch, cellular
system, meteorological sensors (wind, temperature, humidity,
irradiance), solar panels, and batteries; and 3) an underwater sensor
package consisting of a Seabird CTD profiler, YSI dissolved oxygen
electrode, Wetlabs transmissometer, and Wetlabs chlorophyll fluorometer.
At regular sampling intervals, ORCA profiles the water column using the
winch and pressure information from the CTD. The data are recorded on
the computer and transmitted to the lab automatically via cellular
communications. Data are presented from a 1-day deployment in May 2000
and from a long-term, 7-month deployment. The dataset reveals the
combination of intermittent stratification mixing and strong seasonal
forcing in this estuarine system. |