The primary objectives of the proposed equipment funds are to design, fabricate and install GPS receiver-equipped floating buoys in the non-coastal region of Lake Erie for improving the temporal and spatial resolutions of "absolute" and near real-time lake elevation measurements. The lake elevation data are to be used to potentially improve forecasting accuracies of the current operational Great Lakes forecast systems, by providing near-real time, geocentric, and interior Lake Erie water level measurements.

The investigation is to provide a demonstration of the use of space geodetic measurement in GPS-buoys for improving temporal and spatial resolutions of measurements for "absolute" lake elevation. The demonstration of the use of GPS-buoy water level instrument indicates that it has the potential to be a viable instrument for measuring lake water level in any part of the lake and to be used for absolute calibration of altimeters, which is critical for global sea level and climate change studies.

Space geodetic measurements are accurate, abundant, all-weather system, and they are ideally suited to be used as a cost-effective data source for a number of environmental research and operational studies in the Great Lakes. Current observations used for environmental monitoring and coastal forecasting systems are tide gauges and GOES and AVHRR imageries, which are not all-weather measurement systems. We propose to study space geodetic measurements as a strong complementary data set to the existing data used for environmental monitoring and Lake Circulation and weather forecasting. GPS-equipped on a floating buoy can measure absolute lake elevations away from coast, and the measurement can also provide Integrated Water Vapor (IWV) which is potentially useful for Lake forecasting.

The space geodetic measurement proposed is the GPS-buoys (geocentric lake elevation, directional wave measurements). It is anticipated that the GPS-buoy measurement can potentially supplement the current use of Great Lakes tide gauge stations as the only source of lake elevation measurements. We will collaborate with NOAA/NGS in the design, fabrication, and installation of a prototype GPS buoy for automated water level and water vapor measurement gathering, which could potentially improve Lake forecasting. The GPS buoy is also planned to be used for radar altimeter calibration, which is critical for climate change and sea level studies.

GPS-Buoy can measure water level anywhere in the lakes and vertical integrated water vapor from nadir and is an all-weather system to enhance Great Lakes forecasting systems.