Evaluation of directly wind-coherent near-inertial surface currents off Oregon using a statistical parameterization and analytical and numerical models

2014 ◽  
Vol 119 (10) ◽  
pp. 6631-6654 ◽  
Author(s):  
Sung Yong Kim ◽  
P. Michael Kosro ◽  
Alexander L. Kurapov
Keyword(s):  
Numerical Models ◽  
Surface Currents ◽  
Inertial Surface

scholarly journals Estimation of Coastal Currents Using a Soft Computing Method: A Case Study in Galway Bay, Ireland

2019 ◽  
Vol 7 (5) ◽  
pp. 157 ◽  
Author(s):  
Lei Ren ◽  
Jianming Miao ◽  
Yulong Li ◽  
Xiangxin Luo ◽  
Junxue Li ◽  
...  
Keyword(s):  
Numerical Model ◽  
Soft Computing ◽  
Initial Conditions ◽  
Numerical Models ◽  
Surface Velocity ◽  
Training Dataset ◽  
Model Parameters ◽  
Surface Currents ◽  
Coastal Currents ◽  
Computing Models

In order to obtain forward states of coastal currents, numerical models are a commonly used approach. However, the accurate definition of initial conditions, boundary conditions and other model parameters are challenging. In this paper, a novel application of a soft computing approach, random forests (RF), was adopted to estimate surface currents for three analysis points in Galway Bay, Ireland. Outputs from a numerical model and observations from a high frequency radar system were used as inputs to develop soft computing models. The input variable structure of soft computing models was examined in detail through sensitivity experiments. High correlation of surface currents between predictions from RF models and radar data indicated that the RF algorithm is a most promising means of generating satisfactory surface currents over a long prediction period. Furthermore, training dataset lengths were examined to investigate influences on prediction accuracy. The largest improvement for zonal and meridional surface velocity components over a 59-h forecasting period was 14% and 37% of root mean square error (RMSE) values separately. Results indicate that the combination of RF models with a numerical model can significantly improve forecasting accuracy for surface currents, especially for the meridional surface velocity component.

On the flushing of Port Phillip Bay: an application of HF ocean radar

1999 ◽  
Vol 50 (6) ◽  
pp. 483 ◽  
Author(s):  
A. Prytz ◽  
M. L. Heron
Keyword(s):  
Numerical Models ◽  
Surface Current ◽  
Coastal Ocean ◽  
Current Data ◽  
Surface Currents ◽  
Tidal Forcing ◽  
Residual Currents ◽  
Tidal Component ◽  
The Matrix ◽  
Ocean Radar

HF ocean radar can produce maps of surface current in coastal ocean and estuarine waters by providing coverage in both the space and time dimensions. The deployment of COSRAD in Port Phillip Bay for two successive five-day periods provided hourly values of surface currents over the topographically complex area at the south end of the bay. Analysis of the current data provided tidal ellipses for the validation of numerical models, with resultant residual currents of the order of 0·05 m s–1. The repeated hourly maps were the basis for producing Lagrangian tracks; most tracks resulted in trapped paths which remained for long periods of time in the matrix of channels and sand-banks. A ‘tidal run’ technique was developed to calculate the length of Lagrangian tracks over one phase (ebb or flood) of the main tidal component. All tidal runs were about equal to, or shorter than, the length of the relevant channel; this indicates that tidal forcing is not effective in flushing the bay. In contrast, the observed residual currents can be an effective flushing agent if they persist for three days or longer. It is suggested that phenomena on the scale of meteorological to seasonal forcing are the effective flushing agents for Port Phillip Bay.

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.

scholarly journals Observations of Near-Inertial Surface Currents at Palau

Oceanography ◽  
2019 ◽  
Vol 32 (4) ◽  
pp. 74-83 ◽  
Author(s):  
Mika Siegelman ◽  
◽  
Mark Merrifield ◽  
Eric Firing ◽  
Jennifer MacKinnon ◽  
...  
Keyword(s):  
Surface Currents ◽  
Inertial Surface

scholarly journals Behaviorally Mediated Larval Transport in Upwelling Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Steven G. Morgan
Keyword(s):  
Continental Shelf ◽  
Numerical Models ◽  
Tidal Flow ◽  
Population Connectivity ◽  
Larval Transport ◽  
Low Flow ◽  
Surface Currents ◽  
Larval Habitats ◽  
Complete Development ◽  
Interspecific Differences

Highly advective upwelling systems along the western margins of continents are widely believed to transport larvae far offshore in surface currents resulting in larval wastage, limited recruitment, and increased population connectivity. However, suites of larval behaviors effectively mediate interspecific differences in the extent of cross-shelf migrations between nearshore adult habitats and offshore larval habitats. Interspecific differences in behavior determining whether larvae complete development in estuaries or migrate to the continental shelf are evident in large estuaries, but they sometimes may be disrupted by turbulent tidal flow or the absence of a low-salinity cue in shallow, low-flow estuaries, which are widespread in upwelling systems. Larvae of most species on the continental shelf complete development in the coastal boundary layer of reduced flow, whereas other species migrate to the mid- or outer shelf depending on how much time is spent in surface currents. These migrations are maintained across latitudinal differences in the strength and persistence of upwelling, in upwelling jets at headlands, over upwelling-relaxation cycles, and among years of varying upwelling intensity. Incorporating larval behaviors into numerical models demonstrates that larvae recruit closer to home and in higher numbers than when larvae disperse passively or remain in surface currents.

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

2011 ◽  
Vol 8 (2) ◽  
pp. 829-872 ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document