A5084924641- Ocean Waves and Remote Sensing
- Radar Systems and Signal Processing
- Underwater Acoustics Research
- Oceanographic and Atmospheric Processes
- Tropical and Extratropical Cyclones Research
- Underwater Vehicles and Communication Systems
- Direction-of-Arrival Estimation Techniques
- Meteorological Phenomena and Simulations
- Coastal and Marine Dynamics
- Radio Wave Propagation Studies
- Oil Spill Detection and Mitigation
- Marine and fisheries research
- Marine and coastal ecosystems
- Arctic and Antarctic ice dynamics
- Advanced SAR Imaging Techniques
- Evaluation and Performance Assessment
- Soil Moisture and Remote Sensing
- Maritime Navigation and Safety
- Atmospheric and Environmental Gas Dynamics
- Tourism, Volunteerism, and Development
- Antenna Design and Analysis
- Ichthyology and Marine Biology
- Wind Turbine Control Systems
- Educational Assessment and Improvement
- Fish Ecology and Management Studies
University of California, Santa Barbara
2004-2024
Earth Science Institute of the Slovak Academy of Sciences
2009
University of Colorado Boulder
2007
A new generation of integrated sea surface temperature (SST) data products are being provided by the Global Ocean Data Assimilation Experiment (GODAE) High-Resolution SST Pilot Project (GHRSST-PP). These combine in near-real time various from several different satellite sensors and situ observations maintain fine spatial temporal resolution needed inputs to operational models. The practical realization such an approach is complicated characteristic differences that exist between measurements...
The performance of a network five CODAR (Coastal Ocean Dynamics Application Radar) SeaSonde high-frequency (HF) radars, broadcasting near 13 MHz and using the Multiple Signal Classification (MUSIC) algorithm for direction finding, is described based on comparisons with an array nine moorings in Santa Barbara Channel Maria basin deployed between June 1997 November 1999. Eight carried vector-measuring current meters (VMCMs), ninth had upward-looking ADCP. Coverage areas HF radars included...
Abstract Dense arrays of surface drifters are used to quantify the flow field on time and space scales over which high-frequency (HF) radar observations measured. Up 13 were repetitively deployed off Santa Barbara San Diego coasts 7 days during 18 months. Each day a regularly spaced grid overlaid 1-km2 (San Diego) or 4-km2 (Santa Barbara) square, located where HF radial data nearly orthogonal, was seeded with drifters. As moved from they retrieved replaced maintain spatially uniform...
We characterize stratification patterns over diel, seasonal, and annual time scales in inshore offshore regions of Lake Victoria, East Africa; determine conditions leading to horizontal exchanges; and, using surface energy budgets derived from local meteorological stations two reanalysis products, address whether depends on advective as opposed processes. The largest change the budget occurred when winds intensified at end long rains, with wind's intensification, duration, spatial extent...
Relative dispersion statistics and related Lagrangian parameters, not well observed in coastal regions, are obtained from situ surface drifter observations presented the context of stochastic models. Clusters GPS tracked drifters, with initial horizontal spacing 5–10 m, were repetitively deployed Santa Barbara Channel July 2004 to June 2005. The drifters sampled their position every 10 min for 1–2 days. Mean square pair separation distance, or relative dispersion, increases approximately...
Abstract HF radars measure ocean surface currents near coastlines with a spatial and temporal resolution that remains unmatched by other approaches. Most employ direction-finding techniques, which obtain the most accurate current data when using measured, rather than idealized, antenna patterns. Simplifying automating pattern measurement (APM) process would improve utility of radar data, since idealized patterns are widely used. A method is presented for obtaining measurements from ships...
Abstract A new method is described employing small drone aircraft for antenna pattern measurements (APMs) of high-frequency (HF) oceanographic radars used observing ocean surface currents. Previous studies have shown that accurate current using HF radar require APMs. The APMs provide directional calibration the receive antennas direction-finding radars. In absence APMs, so-called ideal patterns are assumed and these can differ substantially from measured patterns. Typically, obtained...
Abstract HF radars typically produce maps of surface current velocities without estimates the measurement uncertainties. Many users radar data, including spill response and search rescue operations, incorporate these observations into models would thus benefit from quantified Using both simulations coincident baseline between two operational SeaSonde radars, we demonstrate utility expressions for estimating uncertainty in direction obtained with Multiple Signal Classification (MUSIC)...
Abstract Submesoscale eddies form an important component of the circulation Southern California Bight (SCB). Despite their acknowledged significance in influencing ocean physics, biology, and ecological processes, submesoscale have been exceptionally hard to study observe because technical challenges posed by both field remote platforms. Here, using a decade high‐frequency radar surface current observations, we describe SCB. Between 2012 2021, total ∼235,000 were detected, averaging 452 ±...
The majority of ocean current measuring HF radars obtain the direction arrival (DOA) signals backscattered from with multiple signal classification (MUSIC) algorithm. These often operate under conditions including low signal-to-noise ratio (SNR), numbers data samples (aka snapshots), and number sources approaching or exceeding receive antenna elements. Improving accuracy coverage radar in these situations would improve produced by networks such as U.S. Integrated Ocean Observing System,...
Abstract While land-based high-frequency (HF) radars are the only instruments capable of resolving both temporal and spatial variability surface currents in coastal ocean, recent high-resolution views suggest that ocean is more complex than presently deployed radar systems able to reveal. This work uses a hybrid system, having elements phased arrays direction finding radars, improve azimuthal resolution HF radars. Data from two along U.S. East Coast configured as 8-antenna grid were used...
The spatial structure of phytoplankton distributions in the mesoscale eddy field North Atlantic (vicinity 20°W, 59°N) was examined with a series high resolution, towed transects. Data were obtained after fall transition August 1991 as part Marine Light-Mixed Layers (MLML) program. Measurements chlorophyll fluorescence (CF) and beam attenuation coefficient anomaly (Δc490) show that particles are confined to surface mixed layer seasonal pycnocline. Two water masses account for potential...
Recent pathways taken by pelagic juvenile fishes to offshore oil platforms were reconstructed from remotely sensed and in situ measurements of currents hydrography. Juvenile comprised 52.8% (16,952 23 species) all individuals (32,080 juveniles adults 35 observed during scuba surveys conducted about twice per week at two the eastern Santa Barbara Channel May August 2004. Blacksmith, Chromis punctipinnis (Cooper, 1863), rockfishes (genus Sebastes , least 18 taxa) 95.1% recruits. Almost...
We describe using small drone aircraft for antenna pattern measurements (APMs) of high-frequency (HF) oceanographic radars observing ocean surface currents. Prior studies show that accurate current HF radar require APMs. Typically APMs are obtained research vessels carrying radio signal sources or transponders in circular arcs around individual sites. This procedure is expensive because it requires sea-going technicians, a vessel, and other equipment necessary to support boat operations....
CODAR Ocean Sensors, Ltd. and the University of California, Santa Barbara are developing a method by which HF radar antenna response patterns can be calibrated automatically over time. Currently, 130 units providing coastal surface current maps to public via U.S. Integrated Observing System (USIOOS): http://www.ioos.gov/hfradar/. These real-time data used for Coast Guard Search Rescue, Hazardous Materials Spills Response, Water Quality Monitoring, Monitoring Harmful Algal Blooms, Fisheries...
Abstract The new system for the inspection of special schools was introduced in England September 1994, using common criteria as those used mainstream schools. One main purposes stated by Office Standards Education (OFSTED) is school improvement. This paper presents perceptions headteachers process arising from first inspections carried out during September‐December 1994. evidence base on these also considered. These data are to suggest that improvement can be enhanced under certain...
High-frequency (HF) ocean radar has the potential to observe sea ice, but this application not been thoroughly investigated. In article, we explore ice observation with HF (HFR) and develop a corresponding signal processing procedure. We derived radial velocities from raw HFR data determined angular positions using MUltiple SIgnal Classification (MUSIC) algorithm. Sea were evaluated by comparison measurements moored acoustic Doppler current profilers (ADCPs) drifting buoy. The...
Advances in oceanographic HF radar processing methods improving the accuracy and resolution of ocean current measurements, would reveal new understanding coastal dynamics. Processing techniques presently employ MUSIC for direction finding, with a low number data snapshots, often SNR. We report on investigation alternative signal methods, including application Maximum Likelihood Estimation (MLE) finding. Simulated backscatter, based realistic flows high-resolution regional model, is used to...
Oceanographic High Frequency (HF) radars are used to monitor coastal ocean conditions, such as waves and surface current velocities, up 250 km from shore in near real-time. Applications using HF radar outputs include search rescue, oil spill response, harmful algal bloom monitoring, tsunami detection, among others. Offshore wind turbines the field of view act strong reflectors can cause interference, leading loss and/or bias oceanographic measurements. With U.S. administration's goal...
Abstract Previous work with simulations of oceanographic high-frequency (HF) radars has identified possible improvements when using maximum likelihood estimation (MLE) for direction arrival; however, methods determining the number emitters (here defined as spatially distinct patches ocean surface) have not realized these improvements. Here we describe and evaluate use ratio (LR) emitter detection, demonstrating its application to HF radar data. The combined detection–estimation MLE-LR are...