Data assimilation with High-Frequency (HF) radar surface currents at a marine renewable energy test site

2015 ◽  
pp. 189-193 ◽  
Author(s):  
L Ren ◽  
S Nash ◽  
M Hartnett
Keyword(s):  
Renewable Energy ◽  
Data Assimilation ◽  
High Frequency ◽  
Test Site ◽  
Hf Radar ◽  
Surface Currents ◽  
Marine Renewable Energy

scholarly journals Forecasting of Surface Currents via Correcting Wind Stress with Assimilation of High-Frequency Radar Data in a Three-Dimensional Model

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Lei Ren ◽  
Stephen Nash ◽  
Michael Hartnett
Keyword(s):  
Data Assimilation ◽  
High Frequency ◽  
Three Dimensional ◽  
Hf Radar ◽  
Surface Velocity ◽  
Shear Stresses ◽  
Surface Currents ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
The Impact

This paper details work in assessing the capability of a hydrodynamic model to forecast surface currents and in applying data assimilation techniques to improve model forecasts. A three-dimensional model Environment Fluid Dynamics Code (EFDC) was forced with tidal boundary data and onshore wind data, and so forth. Surface current data from a high-frequency (HF) radar system in Galway Bay were used for model intercomparisons and as a source for data assimilation. The impact of bottom roughness was also investigated. Having developed a “good” water circulation model the authors sought to improve its forecasting ability through correcting wind shear stress boundary conditions. The differences in surface velocity components between HF radar measurements and model output were calculated and used to correct surface shear stresses. Moreover, data assimilation cycle lengths were examined to extend the improvements of surface current’s patterns during forecasting period, especially for north-south velocity component. The influence of data assimilation in model forecasting was assessed using a Data Assimilation Skill Score (DASS). Positive magnitude of DASS indicated that both velocity components were considerably improved during forecasting period. Additionally, the improvements of RMSE for vector direction over domain were significant compared with the “free run.”

Backtracking drifting objects using surface currents from high-frequency (HF) radar technology

2012 ◽  
Vol 62 (7) ◽  
pp. 1073-1089 ◽  
Author(s):  
Ana Julia Abascal ◽  
Sonia Castanedo ◽  
Vicente Fernández ◽  
Raúl Medina
Keyword(s):  
High Frequency ◽  
Hf Radar ◽  
Surface Currents

Development of Wireless Control System With Underwater Fish-Eye Camera to Monitor Fish at the Test Site of Marine Renewable Energy

2019 ◽  
Author(s):  
Takero Yoshida ◽  
Yoichi Mizukami ◽  
Jinxin Zhou ◽  
Daisuke Kitazawa
Keyword(s):  
Renewable Energy ◽  
Real Time ◽  
Test Site ◽  
Energy Device ◽  
Camera System ◽  
Wireless Monitoring ◽  
Marine Renewable Energy ◽  
Wireless Control ◽  
Before And After ◽  
Fish Eye

Abstract Environmental impact assessment is important when marine renewable energy device is installed. Fishermen concern the effect of device on local fish. To confirm the effect before and after installation of marine renewable energy device, we developed wireless monitoring system using an underwater fish eye camera. The camera system is composed of a dome-shaped fish eye lens, a container, and a float. Two thrusters are attached on the container to change the monitoring directions. In the current research, this system was developed to monitor underwater situation around device remotely and in real time. We tested to monitor a target and fish in a fish case at the site off Kamaishi city. The recorded video showed the target and fish. Effectiveness of this system was shown through the field test for real time monitoring around marine renewable energy device.

scholarly journals Estimation of currents using SARAL/AltiKa in the coastal regions of India

2014 ◽  
Vol XL-8 ◽  
pp. 1365-1367
Author(s):  
A. Chaudhary ◽  
N. Agarwal ◽  
R. Sharma
Keyword(s):  
High Frequency ◽  
Coastal Region ◽  
Hf Radar ◽  
Altimeter Data ◽  
Surface Currents ◽  
Radar Observations ◽  
Geostrophic Currents ◽  
The Moment ◽  
Track Surface ◽  
Along Track

The present study explores the possibility of deriving the across track currents along the Indian coastal region from SARAL/AltiKa mission. The across track surface geostrophic currents obtained from along track SARAL altimeter data are directly compared (qualitatively) with high frequency (HF) radar observations of surface currents in the Bay of Bengal. The velocity component from HF radar which is perpendicular to the altimeter tracks is considered. Since the ageostrophic velocity contribution is ignored for the moment, the surface geostrophic currents SARAL compare well only under low wind conditions. Due to high along track resolution of SARAL there are large variations in velocity which are not captured by the HF radar observations. In general, the magnitude and variations in surface currents derived from SARAL altimeter are comparable with HF radar observations.

scholarly journals Coastal observing and forecasting system for the German Bight – estimates of hydrophysical states

Ocean Science ◽  
2011 ◽  
Vol 7 (5) ◽  
pp. 569-583 ◽  
Author(s):  
E. V. Stanev ◽  
J. Schulz-Stellenfleth ◽  
J. Staneva ◽  
S. Grayek ◽  
J. Seemann ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Data Assimilation ◽  
German Bight ◽  
Numerical Models ◽  
Coastal Ocean ◽  
Hf Radar ◽  
Optimal Interpolation ◽  
Surface Currents ◽  
Arctic Seas

Abstract. A coastal observing system for Northern and Arctic Seas (COSYNA) aims at construction of a long-term observatory for the German part of the North Sea, elements of which will be deployed as prototype modules in Arctic coastal waters. At present a coastal prediction system deployed in the area of the German Bight integrates near real-time measurements with numerical models in a pre-operational way and provides continuously state estimates and forecasts of coastal ocean state. The measurement suite contributing to the pre-operational set up includes in situ time series from stationary stations, a High-Frequency (HF) radar system measuring surface currents, a FerryBox system and remote sensing data from satellites. The forecasting suite includes nested 3-D hydrodynamic models running in a data-assimilation mode, which are forced with up-to-date meteorological forecast data. This paper reviews the present status of the system and its recent upgrades focusing on developments in the field of coastal data assimilation. Model supported data analysis and state estimates are illustrated using HF radar and FerryBox observations as examples. A new method combining radial surface current measurements from a single HF radar with a priori information from a hydrodynamic model is presented, which optimally relates tidal ellipses parameters of the 2-D current field and the M2 phase and magnitude of the radials. The method presents a robust and helpful first step towards the implementation of a more sophisticated assimilation system and demonstrates that even using only radials from one station can substantially benefit state estimates for surface currents. Assimilation of FerryBox data based on an optimal interpolation approach using a Kalman filter with a stationary background covariance matrix derived from a preliminary model run which was validated against remote sensing and in situ data demonstrated the capabilities of the pre-operational system. Data assimilation significantly improved the performance of the model with respect to both SST and SSS and demonstrated a good skill not only in the vicinity of the Ferry track, but also over larger model areas. The examples provided in this study are considered as initial steps in establishing new coastal ocean products enhanced by the integrated COSYNA-observations and numerical modelling.

Investigation of Monitoring Fish Using Underwater Fish-Eye Camera at the Test Site of Marine Renewable Energy

2018 ◽  
Author(s):  
Takero Yoshida ◽  
Daisuke Kitazawa ◽  
Yoichi Mizukami ◽  
Qiaochu Chen ◽  
Akito Mochizuki
Keyword(s):  
Renewable Energy ◽  
Test Site ◽  
Wave Power ◽  
Energy Device ◽  
Power Generator ◽  
Horizontal Visibility ◽  
Marine Renewable Energy ◽  
Before And After ◽  
Fish Eye ◽  
Iwate Prefecture

Assessment of any significant effects on the local marine environment when considering the installation of a marine renewable energy device is of the utmost importance. In particular, the effect of such device on fish is concerned by local fishermen. To confirm variation of fish before and after installing the device of marine renewable energy, we investigated effective monitoring system using an underwater fish-eye camera. In this paper, visibility of the fish-eye camera was tested off Kamaishi city, Iwate prefecture, Japan, which is a test site of marine renewable energy in Japan. Device of wave power generation is planning to install at this site in the future. We confirmed the visibility of the fish-eye camera using a fish-shaped target by changing the distance between the target and camera. The water depth and photon were simultaneously measured. From the result, the horizontal visibility was discussed, and then we made a plan to observe around wave power generator using this fish-eye camera.

scholarly journals A new Lagrangian-based short-term prediction methodology for high-frequency (HF) radar currents

Ocean Science ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. 755-768
Author(s):  
Lohitzune Solabarrieta ◽  
Ismael Hernández-Carrasco ◽  
Anna Rubio ◽  
Michael Campbell ◽  
Ganix Esnaola ◽  
...  
Keyword(s):  
Real Time ◽  
High Frequency ◽  
Skill Score ◽  
Hf Radar ◽  
Surface Currents ◽  
Short Term ◽  
High Frequency Radar ◽  
Term Prediction ◽  
Short Term Prediction ◽  
Temporal Horizon

Abstract. The use of high-frequency radar (HFR) data is increasing worldwide for different applications in the field of operational oceanography and data assimilation, as it provides real-time coastal surface currents at high temporal and spatial resolution. In this work, a Lagrangian-based, empirical, real-time, short-term prediction (L-STP) system is presented in order to provide short-term forecasts of up to 48 h of ocean currents. The method is based on finding historical analogs of Lagrangian trajectories obtained from HFR surface currents. Then, assuming that the present state will follow the same temporal evolution as the historical analog, we perform the forecast. The method is applied to two HFR systems covering two areas with different dynamical characteristics: the southeast Bay of Biscay and the central Red Sea. A comparison of the L-STP methodology with predictions based on persistence and reference fields is performed in order to quantify the error introduced by this approach. Furthermore, a sensitivity analysis has been conducted to determine the limit of applicability of the methodology regarding the temporal horizon of Lagrangian prediction. A real-time skill score has been developed using the results of this analysis, which allows for the identification of periods when the short-term prediction performance is more likely to be low, and persistence can be used as a better predictor for the future currents.

Sign in / Sign up

Export Citation Format

Share Document