Seminar in Applied Mathematics

Michael Bruno Department of Civil, Environmental, and Ocean Engineering Stevens Institute of Technology Real-time nearshore wave measurement and forecast system: Preliminary results Monday,November 15, 1999 3:00pm Morton 105

Abstract:   The New Jersey - Long Island coastal region, bounded on the north by the Hudson-Raritan estuary and Long Island and on the south by Delaware Bay, is characterized by a wave climate with extreme spatial variability. Wave dynamics along the northern coastlines are dominated by the sheltering influence of Long Island, as well as the topographic influence of the Hudson Canyon. As a result waves from the south of east quadrant dominate the northern New Jersey and Long Island regions and waves from the north of east quadrant dominate the southern New Jersey region. Additional nearshore variability occurs as a result of the localized influence of the numerous tidal inlets along the two shorelines. This variability has a profound influence on the shoreline response to tropical and extratropical storms, with important ramifications to both hazard mitigation efforts and commercial and recreational uses of the nearshore environment. Stevens Institute of Technology recently established the New Jersey Coastal Monitoring Network (CMN). This system provides real-time observations and archived records of shallow water (5m) wave, water level and meteorological conditions (wind speed and direction, temperature, atmospheric pressure), as well as digital images of the beach and nearshore, at three locations - Avalon, Long Beach Township, and Spring Lake - that span the State's ocean shoreline. This information is disseminated via the Internet through the Davidson Laboratory's web site: http://www.dl.stevens.edu. The system is designed to provide: 1) real-time information to local, State, and Federal emergency management personnel; and 2) long-term records of wave and weather conditions, and shoreline response for use by the coastal scientific community. The observational network is being combined with an existing wave transformation model and WAM deepwater wave forecasts to create a wave measurement and forecasting system covering the entire New Jersey and Long Island coastal ocean region, including shallow nearshore and offshore deepwater areas. The system will provide real-time observations at the three shallow water locations along the New Jersey shoreline, and 12-to-72 hour forecasts of wave conditions throughout the region. As part of this effort, we first examined the wave transformation patterns throughout the region. Synoptic measurements of incident deepwater wave conditions at NOAA buoys 44025 and 44009 and nearshore conditions at the three CMN stations and at two Army Corps of Engineers shallow (10m) wave gauges at Long Branch, (northern) New Jersey and Westhampton, Long Island were employed in the analysis. These measurements, combined with the local wind observations at each measurement location, were employed to examine several factors of concern to the eventual forecasting scheme, including the spatial variability in the wave climate associated with the sheltering of incident deepwater waves from the north, and the potentially significant role of local winds - including the highly variable contribution of fetch-limited windsea and wave dissipation through white capping.

Refreshments immediately following the talk. For additional information contact Patrick Miller  or Yi Li.