A Near-Real-Time Web-Based Robotic Monitoring Station on Cayuga Lake, New York

摘要

An autonomous Remote Underwater Sampling Station (RUSS) was deployed at the 25m isobath inrnmesotrophic Cayuga Lake, Ithaca, New York on June 6, 2001. Cayuga Lake is deep (max depth 132rnm), long (61 km), and narrow (mean width 2.8 km) with principal axis oriented in the north-southrndirection and has predominantly north-south winds. Several short-term studies (e.g. Birge and Judayrn1914) have been conducted on Cayuga Lake but published long-term water quality and physicalrnprocess studies are lacking.rnThe RUSS is a solar powered system composed of a remotely operated buoyancy controlled profilerrnequipped with a water quality multiparameter probe, a meteorological station, and two-way 900rnMHz communications to land enabling modification of instrument operation as well as data upload.rnThe multiparameter probe measures temperature, conductivity, pH, oxidation-reduction potentialrn(ORP), dissolved oxygen, chlorophyll a, turbidity, chloride, as well as upwelling and downwellingrnphotosynthetically active radiation (PAR). The meteorological station monitors wind speed, windrndirection, air temperature, relative humidity, irradiance, and surface water temperature. The RUSSrnis equipped with an RS-232 data communications system, making it easy to incorporate otherrninstrumentation (e.g. an Acoustic Doppler Current Profiler – or ADCP). Data from the RUSS isrnprovided in near-real-time in graphical form to a web site, www.cayugalake.cornell.edu. The RUSSrnunit is advantageous for researchers and citizens, allowing easy access to long temporal and verticalrnspatial data via the internet.rnThe vertical spatial resolution of the RUSS allows the investigation of physical and biologicalrnprocesses and their interactions. As examples, temperature and conductivity data show evidence ofrnstrong non-linear internal seiche events that lead to upwelling and, as shown by turbidityrnmeasurements, can resuspend sediment. Chlorophyll a levels exhibit a subsurface maximum andrndissolved oxygen measurements exhibit a metalimnetic minimum (negative heterograde curve)rnsuggesting significant coupled interactions of vertical turbulent fluxes and biological sources andrnsinks.