Hans Graber

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High-frequency (HF) radar systems can provide periodic, two-dimensional, vector current estimates over an area approaching 1000 km •. As the use of these HF systems has gained wider acceptance, a number of attempts have been made to estimate the accuracy of such systems. However, comparisons of HF radar current estimates with in situ sensors are difficult(More)
Surface currents measured by HF Doppler radar as part of a study of the Chesapeake Bay outflow plume are examined using a 'real-vector' empirical orthogonal function (EOF) analysis (Kaihatu et al., 1998). Based on about 23 days of nearly continuous data, the analysis shows that the first three EOF modes, judged to be the only significant modes, account for(More)
surface currents were measured using the high-frequency (25.4 MHz) mode of the Ocean Surface Current Radar at 20-min intervals at a horizontal resolution of 1 km over an approximate 30 km ϫ 44 km domain. Comparisons to subsurface current measurements at 1–2 m beneath the surface from two broadband acoustic Doppler current profilers (ADCP) revealed good(More)
Ocean surface current measurements from high-frequency (HF) radar are assessed by comparing these data to near-surface current observations from 1 to 30 October 1994 at two moored subsurface current meter arrays (20 and 25 m) instrumented with vector-measuring current meters (VMCMs) and Seacat sensors during the Duck94 experiment. A dual-station ocean(More)
The validation of estimates of ocean surface current speed and direction from high-frequency (HF) Doppler radars can be obtained through comparisons with measurements from moored near-surface current meters, acoustic Doppler current profilers, or drifters. Expected differences between current meter (CM) and HF radar estimates of ocean surface vector(More)
(SURA) has advanced the SURA Coastal Ocean Observing and Prediction (SCOOP) program as a multi-institution collaboration to design and prototype a modular, distributed system for real-time prediction and visualization of the coastal impacts from extreme atmospheric events, including hurricane inundation and waves. The SCOOP program vision is a community "(More)
The Southeastern University Research Association (SURA) Coastal Ocean Observing and Prediction (SCOOP) program includes university, government, and private sector partners working together to implement Information Technology solutions. The SCOOP program goal is a modular and distributed system for predicting and visualizing the coastal response to extreme(More)
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Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis, sediment and(More)