The Oceanic Remote Chemical Analyzer (ORCA) is an autonomous moored profiling system providing real-time data streams of water and atmospheric conditions. It consists of a profiling underwater sensor package with a variety of chemical and optical sensors, and a surface mounted weather station, solar power system, winch, and custom computer and software package equipped with WIFI/cellular communication.
Since its deployment in 2000, the ORCA system has provided a near-continual stream of high-resolution water quality data from locations in the Puget Sound, Washington State. There are currently 6 mooring systems deployed, spread throughout Puget Sound and Hood Canal.
The original goal of the ORCA project was to develop a robust remote chemical and biological monitoring system that could:
- incorporate a large variety of sensors to allow monitoring of key water and atmospheric parameters, such as:
- temperature, salinity, solar radiation, wind speed and direction
- nutrient, oxygen, and chlorophyll concentraitons, turbidity
- gas exchange parameters
- and currents
- monitor the spectrum of time-scales, including hourly (tidal flucuations), daily (solar cycles), weekly and monthly (plankton growth and blooms), and annual (seasons and inter-annual cycles, i.e. El Nino)
- telemeter data back in near-real time
Now that the system has been developed, the project has been able to focus on the analysis of the high frequency database the ORCA system has collected. While we will continue to develop the flexibility, expandability, and robustness of the system, our current goals are to:
- use the high frequency data set to describe natural variability and characterize and help evaluate potential human influences
- validate current physical and biological models for the Puget Sound
- develop ORCA as a learning tool
- allowing access to the high-resolution time series to undergraduate and graduate students who design and execute experiments
- use the time-series as a real world example to teach oceanographic concepts to area middle and high school science classes
The high frequency data set produced by the ORCA project allows investigation of many key questions relevant to the Puget Sound, especially the area of South Puget Sound and Hood Canal:
- What are the relative roles of Tidal (12.2 hr), Diel (24 hr), Bloom (week-month), Seasonal (year), and El Nino (inter-annual) cycles?
- To what relative extents are phytoplankton blooms in this region dependent on: stratification, insolation and nutrients?
- Are human-derived nutrient inputs currently small relative to natural (physical and biological) fluxes?
- Will increases in nutrient inputs (eutrophication) as population and industrialization increase adversely impact water quality in South Puget Sound?
- What are the key factors in the cause of hypoxia in southern Hood Canal?
ORCA consists of a surface ATLAS float in a 3-point mooring configuration. The float has a platform, which supports a Linux micro-computer, wifi communications system, marine batteries, solar panels, meteorological station and an electric winch with slip rings. A Seabird CTD package at the end of a conducting cable provides pressure information to the surface computer, which in turn drives the winch. Weather and CTD data is transmitted back to the University of Washington lab after each cast.
SBE 19plus v2 SEACAT Profiler, SBE 19plus SEACAT Profiler
SBE 43 Oxygen sensor
SeaFET pH Sensor
ECO FLNTU Fluorometer and Turbidity Sensor
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