Todd Fake

The Physical Oceanography of Long Island Sound

Coastal ocean ecosystems are strongly influenced by circulation, tides, waves, and the rates of mixing of the water. Many shoreline communities are increasingly threatened by the same phenomena, most notably through flooding and coastal erosion. In this review we summarize the observations that have been acquired in LIS to describe and explain the magnitude and variability of these physical processes. We also comment on the status of our theoretical understanding of the links between them and some of their consequences. Analysis of available buoy and coastal wind observations suggests that the shear stress due to wind over LIS is under-predicted by a factor of between 2 and 3 if shore station winds are used to make the estimates. This difference is significant to both water quality and wave forecasting. We describe the magnitude of seasonal variations in wind and waves and use long-term records from coastal stations to show that there are decadal-scale variations in both wind speed and directions. Available wave data from two buoys suggest that the wave field is consistent with that predicted by fetch- limited wind forcing. Semi-diurnal tidal sea level variations and vertically averaged currents are well described by theoretical models, however, recent observations show high amplitude over tides in the western LIS that remain to be explained. The vertical structure of the tidal currents is much more complex and a closer examination of model predictions, particularly of the across Sound velocity components, should be conducted. The interaction of the vertical structure of tidal currents and the salinity and temperature distributions may lead to significant heat and salt transport vertically and horizontally. Observations of the mean density, temperature, and salt distributions and the mean circulation in LIS are qualitatively consistent with several models and we summarize the recent work. A more critical evaluation is now appropriate. We also discuss evidence of long-term trends. The role of shorter time-scale meteorological forcing and the bathymetry of the Sound on the structure and variability of the circulation is summarized using observations and simulation. Long-term observations of both hypoxia duration and hypoxia areal extent in western and west central Long Island Sound are analyzed to determine the directional response to wind forcing. We show that a substantial fraction of the inter-annual variability in area and duration can be explained by the directional statistics of wind. Using simulation, we demonstrate that the geometry of the basin and across isobath flow may be significant. The response of the Sound to severe storms is outlined and the technical developments in simulation and observation that are necessary to the improvement of model predictions are suggested.

National IOOS high frequency radar search and rescue project

The U.S. Integrated Ocean Observing System (IOOS®) partners have begun an effort to extend the use of high frequency (HF) radar for U.S. Coast Guard (USCG) search and rescue operations to all U.S. coastal areas with HF radar coverage. This project builds on the success of an IOOS and USCG-supported regional USCG search and rescue product created by Applied Science Associates (ASA), Rutgers University and University of Connecticut for the mid-Atlantic region. We describe the regional product and the expanded national products two main components: optimally-interpolated velocity fields and a predicted velocity field.

Chapter 10 – How High-Resolution Wave Observations and HF Radar–Derived Surface Currents are Critical to Decision-Making for Maritime Operations

Abstract This paper will primarily focus on the value of high-resolution wave measurements and high-frequency (HF) radar–derived surface currents on maritime operations, and the contributions of the Coastal Data Information Program (CDIP) and the Coastal Observing Research and Development Center (CORDC) on those measurements, respectively. Use case scenarios are presented to demonstrate operational applications utilizing wave and surface current measurements. Both CDIP and CORDC are based at the Scripps Institution of Oceanography and rely on multiple partnerships and collaborations. CDIP, primarily funded by the United States Army Corps of Engineers, manages and ingests data from over 60 coastal wave buoys, many of them at entries to ports and harbors, supporting near shore navigation. CORDC manages the data acquisition and near real-time processing of the U.S. High Frequency Radar network (HFRNet), a network that includes numerous participating organizations. These programs work in partnership with the U.S. Integrated Ocean Observing System (IOOS ® ). IOOS provides vital collaborations enabling tracking, predicting, managing, and adapting to changes in our ocean, coastal, and Great Lakes environment. Discussions continue with the commercial and recreational maritime community as to which types of observational products are needed in order to improve safety and efficiency. Both the wave and surface current data are available through web services and the IOOS regional organizations, such as the Southern California Coastal Ocean Observing system (SCCOOS).