scholarly journals Prediction of geostrophic currents using big weather data archive and neural networks for the Aegean Sea

2019 ◽  
Vol 9 (1) ◽  
pp. 10-20
Author(s):  
Timur İnan ◽  
Ahmet Fevzi BABA
Keyword(s):  
Neural Network ◽  
Surface Current ◽  
Aegean Sea ◽  
Current Data ◽  
Sea Surface ◽  
Weather Data ◽  
Time Of Arrival ◽  
Surface Currents ◽  
Data Archive ◽  
Wave Direction

Prediction of sea and weather environment variables like wind speed, wind direction, wave height, wave direction, sea surface current direction and magnitude has always been an important subject in marine engineering as they effect on ship speed and effect the time of arrival to destination point as well. In this study, we propose a neural network that can predict the latitudinal and longitudinal components of sea surface currents in the Aegean Sea. The system can predict the sea surface currents components using the wind components which are gathered from the INMARSAT weather report system. The neural network is trained using the historical data which is gathered from UCAR historical weather database and historical surface current data which is gathered from IFREMER database. Keywords: Sea surface current, weather report, prediction, neural network, big data archive.

scholarly journals Gap Filling of the CALYPSO HF Radar Sea Surface Current Data through Past Measurements and Satellite Wind Observations

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Adam Gauci ◽  
Aldo Drago ◽  
John Abela
Keyword(s):  
Oil Spills ◽  
Surface Current ◽  
Radar Data ◽  
Current Data ◽  
Hf Radar ◽  
Sea Surface ◽  
Machine Learning Techniques ◽  
Learning Techniques ◽  
Spatial Coverage ◽  
Essential Components

High frequency (HF) radar installations are becoming essential components of operational real-time marine monitoring systems. The underlying technology is being further enhanced to fully exploit the potential of mapping sea surface currents and wave fields over wide areas with high spatial and temporal resolution, even in adverse meteo-marine conditions. Data applications are opening to many different sectors, reaching out beyond research and monitoring, targeting downstream services in support to key national and regional stakeholders. In the CALYPSO project, the HF radar system composed of CODAR SeaSonde stations installed in the Malta Channel is specifically serving to assist in the response against marine oil spills and to support search and rescue at sea. One key drawback concerns the sporadic inconsistency in the spatial coverage of radar data which is dictated by the sea state as well as by interference from unknown sources that may be competing with transmissions in the same frequency band. This work investigates the use of Machine Learning techniques to fill in missing data in a high resolution grid. Past radar data and wind vectors obtained from satellites are used to predict missing information and provide a more consistent dataset.

Gaps Filling in HF Radar Sea Surface Current Data Using Complex Empirical Orthogonal Functions

2020 ◽  
Vol 177 (12) ◽  
pp. 5969-5992
Author(s):  
Siva Srinivas Kolukula ◽  
Balaji Baduru ◽  
P. L. N. Murty ◽  
J. Pavan Kumar ◽  
E. Pattabhi Rama Rao ◽  
...  
Keyword(s):  
Surface Current ◽  
Current Data ◽  
Empirical Orthogonal Functions ◽  
Hf Radar ◽  
Sea Surface ◽  
Orthogonal Functions

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 Improving the Altimeter-Derived Surface Currents Using Sea Surface Temperature (SST) Data: A Sensitivity Study to SST Products

2020 ◽  
Vol 12 (10) ◽  
pp. 1601 ◽  
Author(s):  
Daniele Ciani ◽  
Marie-Hélène Rio ◽  
Bruno Buongiorno Nardelli ◽  
Hélène Etienne ◽  
Rosalia Santoleri
Keyword(s):  
High Resolution ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Surface Current ◽  
Zonal Flow ◽  
Sensitivity Study ◽  
Sea Surface ◽  
Global Network ◽  
Altimeter Data ◽  
Surface Currents

Measurements of ocean surface topography collected by satellite altimeters provide geostrophic estimates of the sea surface currents at relatively low resolution. The effective spatial and temporal resolution of these velocity estimates can be improved by optimally combining altimeter data with sequences of high resolution interpolated (Level 4) Sea Surface Temperature (SST) data, improving upon present-day values of approximately 100 km and 15 days at mid-latitudes. However, the combined altimeter/SST currents accuracy depends on the area and input SST data considered. Here, we present a comparative study based on three satellite-derived daily SST products: the Remote Sensing Systems (REMSS, 1/10 ∘ resolution), the UK Met Office OSTIA (1/20 ∘ resolution), and the Multiscale Ultra-High resolution SST (1/100 ∘ resolution). The accuracy of the marine currents computed with our synergistic approach is assessed by comparisons with in-situ estimated currents derived from a global network of drifting buoys. Using REMSS SST, the meridional currents improve up to more than 20% compared to simple altimeter estimates. The maximum global improvements for the zonal currents are obtained using OSTIA SST, and reach 6%. Using the OSTIA SST also results in slight improvements (≃1.3%) in the zonal flow estimated in the Southern Ocean (45 ∘ S to 70 ∘ S). The homogeneity of the input SST effective spatial resolution is identified as a crucial requirement for an accurate surface current reconstruction. In our analyses, this condition was best satisfied by the lower resolution SST products considered.

scholarly journals Satellite-Derived Surface Current Divergence in Relation to Tropical Atlantic SST and Wind

2007 ◽  
Vol 37 (5) ◽  
pp. 1357-1375 ◽  
Author(s):  
Robert W. Helber ◽  
Robert H. Weisberg ◽  
Fabrice Bonjean ◽  
Eric S. Johnson ◽  
Gary S. E. Lagerloef
Keyword(s):  
Atlantic Ocean ◽  
Velocity Component ◽  
Surface Current ◽  
Sea Surface ◽  
Surface Currents ◽  
Tropical Atlantic ◽  
Cold Tongue ◽  
Equatorial Atlantic ◽  
Zonal Velocity ◽  
Mass Divergence

Abstract The relationships between tropical Atlantic Ocean surface currents and horizontal (mass) divergence, sea surface temperature (SST), and winds on monthly-to-annual time scales are described for the time period from 1993 through 2003. Surface horizontal mass divergence (upwelling) is calculated using surface currents estimated from satellite sea surface height, surface vector wind, and SST data with a quasi-linear, steady-state model. Geostrophic and Ekman dynamical contributions are considered. The satellite-derived surface currents match climatological drifter and ship-drift currents well, and divergence patterns are consistent with the annual north–south movement of the intertropical convergence zone (ITCZ) and equatorial cold tongue evolution. While the zonal velocity component is strongest, the meridional velocity component controls divergence along the equator and to the north beneath the ITCZ. Zonal velocity divergence is weaker but nonnegligible. Along the equator, a strong divergence (upwelling) season in the central/eastern equatorial Atlantic peaks in May while equatorial SST is cooling within the cold tongue. In addition, a secondary weaker and shorter equatorial divergence occurs in November also coincident with a slight SST cooling. The vertical transport at 30-m depth, averaged across the equatorial Atlantic Ocean between 2°S and 2°N for the record length, is 15(±6) × 106 m3 s−1. Results are consistent with what is known about equatorial upwelling and cold tongue evolution and establish a new method for observing the tropical upper ocean relative to geostrophic and Ekman dynamics at spatial and temporal coverage characteristic of satellite-based observations.

scholarly journals Surface currents in the Porsanger fjord in northern Norway

2016 ◽  
Vol 37 (3) ◽  
pp. 337-360 ◽  
Author(s):  
Malgorzata Stramska ◽  
Andrzej Jankowski ◽  
Agata Cieszyńska
Keyword(s):  
Sea Level ◽  
Barents Sea ◽  
Surface Current ◽  
Current Data ◽  
Tidal Range ◽  
Surface Currents ◽  
Tidal Component ◽  
Level Data ◽  
Sea Level Oscillations ◽  
Tidal Constituents

Abstract We describe surface currents in the Porsanger fjord (Porsangerfjorden) located in the European Arctic in the vicinity of the Barents Sea. Our analysis is based on surface current data collected in the summer of 2014 using High Frequency (WERA, Helzel Messtechnik GmbH) radar system. One of our objectives was to separate out the tidal from the nontidal components of the currents and to determine the most important tidal constituents. Tides in the Porsanger fjord are substantial, with tidal range on the order of about 3 m. Tidal analysis attributes to tides about 99% of variance in sea level time series recorded in Honningsvaag. The most important tidal component in sea level data is the M2 component, with amplitude of ~90 cm. The S2 and N2 constituents (amplitude of ~20 cm) also play a significant role in the semidiurnal sea level oscillations. The most important diurnal component is K1 with amplitude of about 8 cm. The most important tidal component in analyzed surface currents records is the M2 component. The second most important component is the S2. Our results indicate that in contrast to sea level, only about 10-30% of variance in surface currents can be attributed to tidal currents. This means that about 70-90% of variance is due to wind-induced and geostrophic currents.

scholarly journals Sea Surface Current Velocity Retrieving from TanDAM-X Satellite Data

2021 ◽  
pp. 1-10
Author(s):  
M. Marghany ◽  
J.L. Genderen
Keyword(s):  
Neural Network ◽  
Coastal Waters ◽  
Optimal Solution ◽  
Surface Current ◽  
Hopfield Neural Network ◽  
Pareto Optimal Solution ◽  
Sea Surface ◽  
Pareto Optimal ◽  
Network Algorithm ◽  
Neural Network Algorithm

This is the first investigation for the use of TanDEM-X data, satellite for the Malaysian coastal waters. This aims at utilizing an optimization of the Hopfield neural network to retrieve variation of sea surface current along Malaysian coastal waters. In doing so, a multi-objective evolutionary algorithm based on the Pareto front is used to minimize the error produced due to non-linearity between TanDEM-X data and sea surface movements. This work aimed at retrieving sea surface current from TanDEM-X data along the coastal waters of Malaysia. Two approaches have been implemented, the Hopfield neural network algorithm and Pareto optimal solution. The study shows that the Pareto optimal solution has a higher performance than the Hopfield neural network algorithm with a lower RMSE of ±0.009. Furthermore, a Pareto optimal solution can determine the sea surface current pattern variation along the coastal water from TanDEM-X data. In conclusion, TanDEM-X data shows an excellent promise for retrieving sea surface currents.

scholarly journals Characteristics of surface currents in Manado Bay, North Sulawesi, Indonesia

2021 ◽  
Vol 5 (1) ◽  
pp. 42-52
Author(s):  
Aulia Dyan Yohanlis ◽  
Mutiara Rachmat Putri
Keyword(s):  
Surface Current ◽  
Current Speed ◽  
Sea Surface ◽  
Marine Debris ◽  
Surface Currents ◽  
Hydrodynamic Simulation ◽  
Average Speed ◽  
Debris Accumulation ◽  
North Sulawesi ◽  
Current Flows

Manado Bay is a complex waterway located in Manado City, North Sulawesi, Indonesia. It is an entry point for the Indonesia Trough-Flow, and its circulation is affected by the seasonal winds. Manado City has no debris net on its river estuaries. Therefore, marine debris can easily be carried away by the ocean currents and accumulate in the tourism areas located along the coast of Manado Bay. Consequently, it is important to study the sea surface current circulation in Manado Bay to deal with marine debris accumulation. In the present study, we utilized the DELFT3D software to simulate the hydrodynamic circulation in Manado Bay from 2016-2017. We conducted a 2-dimension (2D) horizontal hydrodynamic simulation using tidal and wind forcing from European Centre for Medium-Range Weather (ECMWF). The simulation results indicate that the change in bathymetry and wind affect the sea surface currents. During the summer monsoon (June-August), the sea surface current flows from the northeast to the southwest with an average speed of 1.1 cm s-1. On the contrary, during the transitional monsoon 1 (September-November), the sea surface current flows from the southeast to the northwest with an average speed of 1.3 cm s-1. Meanwhile, in the winter monsoon (December-February), the sea surface current originated from the southwest flows to the east with an average velocity of 1.9 cm s-1. Then, it moves from west to east during transitional monsoon 2 (March-May) with an average speed of 1.5 cm s-1. The current speed increases whenthe water enters the strait between the Bunaken Islands due to refraction, diffraction, and shallowing effect. As current flows toward the shallower area, the current speed increases, compensating the water column reduction.

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