Journal articles: 'Ocean currents'

1

Jones, David. "Ocean currents." Nature 334, no. 6182 (August 1988): 476. http://dx.doi.org/10.1038/334476a0.

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Wullenweber, Nellie, Lars R. Hole, Peygham Ghaffari, Inger Graves, Harald Tholo, and Lionel Camus. "SailBuoy Ocean Currents: Low-Cost Upper-Layer Ocean Current Measurements." Sensors 22, no. 15 (July 25, 2022): 5553. http://dx.doi.org/10.3390/s22155553.

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This study introduces an alternative to the existing methods for measuring ocean currents based on a recently developed technology. The SailBuoy is an unmanned surface vehicle powered by wind and solar panels that can navigate autonomously to predefined waypoints and record velocity profiles using an integrated downward-looking acoustic Doppler current profiler (ADCP). Data collected on two validation campaigns show a satisfactory correlation between the SailBuoy current records and traditional observation techniques such as bottom-mounted and moored current profilers and moored single-point current meter. While the highest correlations were found in tidal signals, strong current, and calm weather conditions, low current speeds and varying high wave and wind conditions reduced correlation considerably. Filtering out some events with the high sea surface roughness associated with high wind and wave conditions may increase the SailBuoy ADCP listening quality and lead to better correlations. Not yet resolved is a systematic offset between the measurements obtained by the SailBuoy and the reference instruments of ±0.03 m/s. Possible reasons are discussed to be the differences between instruments (various products) as well as changes in background noise levels due to environmental conditions.

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Cheng, Tianyi, Zhaohui Chen, Jingkai Li, Qing Xu, and Haiyuan Yang. "Characterizing the Effect of Ocean Surface Currents on Advanced Scatterometer (ASCAT) Winds Using Open Ocean Moored Buoy Data." Remote Sensing 15, no. 18 (September 21, 2023): 4630. http://dx.doi.org/10.3390/rs15184630.

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The ocean surface current influences the roughness of the sea surface, subsequently affecting the scatterometer’s measurement of wind speed. In this study, the effect of surface currents on ASCAT-retrieved winds is investigated based on in-situ observations of both surface winds and currents from 40 open ocean moored buoys in the tropical and mid-latitude oceans. A total of 28,803 data triplets, consisting of buoy-observed wind vectors, current vectors, and ASCAT Level 2 wind vectors, were collected from the dataset spanning over 10 years. It is found that the bias between scatterometer-retrieved wind speed and buoy-observed wind speed is negatively correlated with the ocean surface current speed. The wind speed bias is approximately 0.96 times the magnitude of the downwind surface current. The root-mean-square error between the ASCAT wind speeds and buoy observations is reduced by about 15% if rectification with ocean surface currents is involved. Therefore, it is essential to incorporate surface current information into wind speed calibration, particularly in regions with strong surface currents.

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Howarth, M. J. "Monitoring Ocean Currents." Physics in Technology 18, no. 6 (November 1987): 235–43. http://dx.doi.org/10.1088/0305-4624/18/6/301.

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Hensel, Michael. "Evolving Synergy: OCEAN Currents, Current OCEANs and Why Networks Must Displace Themselves." Architectural Design 76, no. 5 (2006): 104–8. http://dx.doi.org/10.1002/ad.331.

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WEAVER, ANDREW J. "Ocean currents and climate." Nature 347, no. 6292 (October 1990): 432. http://dx.doi.org/10.1038/347432a0.

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Berry, Paula. "Ocean currents and climate." Physics Bulletin 38, no. 11 (November 1987): 410. http://dx.doi.org/10.1088/0031-9112/38/11/016.

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Tweedie, M. Sara, Diane M. Stanitski, H. David Snyder, and Jennifer N. Hammond. "Follow the World's Ocean Currents with the Ocean Surface Currents Web Site and the Adopt a Drifter Program." Marine Technology Society Journal 39, no. 4 (December 1, 2005): 83–89. http://dx.doi.org/10.4031/002533205787465940.

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The ocean surface has provided the interface for commerce, adventure and exploration for millennia. Studies of ocean surface currents play a vital role in our present day understanding of the dynamics at this ocean-atmosphere interface. Using technology to bridge vast distances, students can now reach the oceans and experience real-life challenges that rival those of the space program. In this paper, we detail two efforts using different approaches to engage teachers and their students in the study of ocean surface currents.The NASA-sponsored Ocean Surface Currents Web site (www.oceanmotion.org) provides a comprehensive review of the surface circulation of Earth's ocean and classroom investigations appropriate for various disciplines at the high school level. The site highlights use of data derived from the online satellite data to understand patterns of ocean surface currents and how they relate to issues of exploration, commerce, marine life, weather/climate, natural hazards and national security. Classroom investigations help high school students practice skills matched to national standards, and keyed to topics covered in the traditional high school curriculum and to the stages of the 5 E's teaching and learning model.The NOAA-sponsored Adopt a Drifter Program (ADP) provides an educational opportunity for K-16 teachers to infuse ocean observing system data into their curriculum. The ADP promotes one-on-one partnerships between schools from the United States and international schools where students from both schools mutually adopt a drifting buoy to be deployed from a ship at sea. An educational sticker from each school is adhered to the drifter before deployment and teachers and their students access drifter location, sea surface temperature and/or sea surface pressure data from the drifter online at http://osmc.noaa.gov/OSMC/adopt_a_drifter.html.These resources better equip teachers with the tools necessary to ignite the interest of students and explain complex relationships between dynamic atmosphere and ocean systems.

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Chacko, Neethu, Meer M. Ali, and Mark A. Bourassa. "Impact of Ocean Currents on Wind Stress in the Tropical Indian Ocean." Remote Sensing 14, no. 7 (March 23, 2022): 1547. http://dx.doi.org/10.3390/rs14071547.

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This study examines the effect of surface currents on the bulk algorithm calculation ofwind stress estimated using the scatterometer data during 2007–2020 in the Indian Ocean. In the study region as a whole, the wind stress decreased by 5.4% by including currents in the wind stress equation. The most significant reduction in the wind stress is found along the most energetic regions with strong currents such as Somali Current, Equatorial Jets, and Agulhas retroflection. The highest reduction of 11.5% is observed along the equator where the Equatorial Jets prevail. A sensitivity analysis has been carried out for the study region and for different seasons to assess the relative impact of winds and currents in the estimation of wind stress by changing the winds while keeping the currents constants and vice versa. The inclusion of currents decreased the wind stress (consistent with scatterometer winds) and this decrease is prominent when the currents are stronger. This study showed that the equatorial Indian Ocean is the most sensitive region where the current can impact wind stress estimation. The results showed that uncertainties in the wind stress estimations are quite large at regional levels and hence better representation of wind stress incorporating ocean currents should be considered in the ocean/climatic models for accurate air-sea interaction studies that are not based on remotely sensed winds.

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Kusnanti, Eka Alifia, Dian C. Rini Novitasari, Fajar Setiawan, Aris Fanani, Mohammad Hafiyusholeh, and Ghaluh Indah Permata Sari. "Predicting Velocity and Direction of Ocean Surface Currents using Elman Recurrent Neural Network Method." Journal of Information Systems Engineering and Business Intelligence 8, no. 1 (April 26, 2022): 21–30. http://dx.doi.org/10.20473/jisebi.8.1.21-30.

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Background: Ocean surface currents need to be monitored to minimize accidents at ship crossings. One way to predict ocean currents—and estimate the danger level of the sea—is by finding out the currents’ velocity and their future direction. Objective: This study aims to predict the velocity and direction of ocean surface currents. Methods: This research uses the Elman recurrent neural network (ERNN). This study used 3,750 long-term data and 72 short-term data. Results: The evaluation with Mean Absolute Percentage Error (MAPE) achieved the best results in short-term predictions. The best MAPE of the U currents (east to west) was 14.0279% with five inputs; the first and second hidden layers were 50 and 100, and the learning rate was 0.3. While the best MAPE of the V currents (north to south) was 3.1253% with five inputs, the first and second hidden layers were 20 and 50, and the learning rate was 0.1. The ocean surface currents’ prediction indicates that the current state is from east to south with a magnitude of around 169,5773°-175,7127° resulting in a MAPE of 0.0668%. Conclusion: ERNN is more effective than single exponential smoothing and RBFNN in ocean current prediction studies because it produces a smaller error value. In addition, the ERNN method is good for short-term ocean surface currents but is not optimal for long-term current predictions. Keywords: MAPE, ERNN, ocean currents, ocean currents’ velocity, ocean currents’ directions

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Ninomiya, Junichi, Nobuhito Mori, Tomohiro Yasuda, Hajime Mase, and Naoto Kihara. "IMPROVEMENT OF STORM SURGE SIMULATION UPON PARAMETERIZATIONS OF COUPLED AIR-SEA INTERACTIONS." Coastal Engineering Proceedings 1, no. 33 (December 15, 2012): 51. http://dx.doi.org/10.9753/icce.v33.currents.51.

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Coupled atmosphere-ocean model has been developed in various organizations. Warner et al. developed fully coupled model, so-called COAWST, using the atmosphere model WRF, the ocean model ROMS and the wave model SWAN. Though there are several studies with coupled model, there is few research on tropical cyclone event analyzing the changes in ocean current and water temperature in detail. In this study, a series of numerical simulations was carried out targeting Typhoon Melor (2009), and it is analyzed against to the meteorologic and oceanic field data at Tanabe bay, Wakayama Prefecture in Japan. The results show that the wave energy dissipation by the wave model is effective in the change of ocean current and the thermal feedback by the atmospheric model is effective in the change of water temperature due to the typhoon passage.

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Callaghan, David P., Thuy T. T. Vu, David J. Hanslow, Peter Nielsen, Zai-Jin You, and Ian Teakle. "OCEAN DRIVEN FLOODING OF A COASTAL LAKE." Coastal Engineering Proceedings 1, no. 34 (October 30, 2014): 47. http://dx.doi.org/10.9753/icce.v34.currents.47.

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Torres, Hector S., Patrice Klein, Jinbo Wang, Alexander Wineteer, Bo Qiu, Andrew F. Thompson, Lionel Renault, et al. "Wind work at the air-sea interface: a modeling study in anticipation of future space missions." Geoscientific Model Development 15, no. 21 (November 7, 2022): 8041–58. http://dx.doi.org/10.5194/gmd-15-8041-2022.

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Abstract. Wind work at the air-sea interface is the transfer of kinetic energy between the ocean and the atmosphere and, as such, is an important part of the ocean-atmosphere coupled system. Wind work is defined as the scalar product of ocean wind stress and surface current, with each of these two variables spanning, in this study, a broad range of spatial and temporal scales, from 10 km to more than 3000 km and hours to months. These characteristics emphasize wind work's multiscale nature. In the absence of appropriate global observations, our study makes use of a new global, coupled ocean-atmosphere simulation, with horizontal grid spacing of 2–5 km for the ocean and 7 km for the atmosphere, analyzed for 12 months. We develop a methodology, both in physical and spectral spaces, to diagnose three different components of wind work that force distinct classes of ocean motions, including high-frequency internal gravity waves, such as near-inertial oscillations, low-frequency currents such as those associated with eddies, and seasonally averaged currents, such as zonal tropical and equatorial jets. The total wind work, integrated globally, has a magnitude close to 5 TW, a value that matches recent estimates. Each of the first two components that force high-frequency and low-frequency currents, accounts for ∼ 28 % of the total wind work and the third one that forces seasonally averaged currents, ∼ 44 %. These three components, when integrated globally, weakly vary with seasons but their spatial distribution over the oceans has strong seasonal and latitudinal variations. In addition, the high-frequency component that forces internal gravity waves, is highly sensitive to the collocation in space and time (at scales of a few hours) of wind stresses and ocean currents. Furthermore, the low-frequency wind work component acts to dampen currents with a size smaller than 250 km and strengthen currents with larger sizes. This emphasizes the need to perform a full kinetic budget involving the wind work and nonlinear advection terms as small and larger-scale low-frequency currents interact through these nonlinear terms. The complex interplay of surface wind stresses and currents revealed by the numerical simulation motivates the need for winds and currents satellite missions to directly observe wind work.

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GOLDSTEIN, R. M., H. A. ZEBKER, and T. P. BARNETT. "Remote Sensing of Ocean Currents." Science 246, no. 4935 (December 8, 1989): 1282–85. http://dx.doi.org/10.1126/science.246.4935.1282.

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15

Day, Charles. "Fish catch and ocean currents." Physics Today 71, no. 4 (April 2018): 23. http://dx.doi.org/10.1063/pt.3.3892.

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McWilliams, James C. "Submesoscale currents in the ocean." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, no. 2189 (May 2016): 20160117. http://dx.doi.org/10.1098/rspa.2016.0117.

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This article is a perspective on the recently discovered realm of submesoscale currents in the ocean. They are intermediate-scale flow structures in the form of density fronts and filaments, topographic wakes and persistent coherent vortices at the surface and throughout the interior. They are created from mesoscale eddies and strong currents, and they provide a dynamical conduit for energy transfer towards microscale dissipation and diapycnal mixing. Consideration is given to their generation mechanisms, instabilities, life cycles, disruption of approximately diagnostic force balance (e.g. geostrophy), turbulent cascades, internal-wave interactions, and transport and dispersion of materials. At a fundamental level, more questions remain than answers, implicating a programme for further research.

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Liang, W. D., T. Y. Tang, Y. J. Yang, M. T. Ko, and W. S. Chuang. "Upper-ocean currents around Taiwan." Deep Sea Research Part II: Topical Studies in Oceanography 50, no. 6-7 (March 2003): 1085–105. http://dx.doi.org/10.1016/s0967-0645(03)00011-0.

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Hays, Graeme C. "Ocean currents and marine life." Current Biology 27, no. 11 (June 2017): R470—R473. http://dx.doi.org/10.1016/j.cub.2017.01.044.

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Fischer, Andrea, Luiz Emílio B. de Almeida, and Alexandre Beluco. "CONVERTING ENERGY FROM OCEAN CURRENTS." International Journal of Research in Engineering and Technology 05, no. 03 (May 25, 2016): 220–27. http://dx.doi.org/10.15623/ijret.2016.0503044.

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Charnock, H. "Ocean currents and meridional transfers." Quarterly Journal of the Royal Meteorological Society 113, no. 475 (January 1987): 3–18. http://dx.doi.org/10.1002/qj.49711347502.

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Irrgang, Christopher, Jan Saynisch-Wagner, and Maik Thomas. "Depth of origin of ocean-circulation-induced magnetic signals." Annales Geophysicae 36, no. 1 (January 29, 2018): 167–80. http://dx.doi.org/10.5194/angeo-36-167-2018.

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Abstract. As the world ocean moves through the ambient geomagnetic core field, electric currents are generated in the entire ocean basin. These oceanic electric currents induce weak magnetic signals that are principally observable outside of the ocean and allow inferences about large-scale oceanic transports of water, heat, and salinity. The ocean-induced magnetic field is an integral quantity and, to first order, it is proportional to depth-integrated and conductivity-weighted ocean currents. However, the specific contribution of oceanic transports at different depths to the motional induction process remains unclear and is examined in this study. We show that large-scale motional induction due to the general ocean circulation is dominantly generated by ocean currents in the upper 2000 m of the ocean basin. In particular, our findings allow relating regional patterns of the oceanic magnetic field to corresponding oceanic transports at different depths. Ocean currents below 3000 m, in contrast, only contribute a small fraction to the ocean-induced magnetic signal strength with values up to 0.2 nT at sea surface and less than 0.1 nT at the Swarm satellite altitude. Thereby, potential satellite observations of ocean-circulation-induced magnetic signals are found to be likely insensitive to deep ocean currents. Furthermore, it is shown that annual temporal variations of the ocean-induced magnetic field in the region of the Antarctic Circumpolar Current contain information about sub-surface ocean currents below 1000 m with intra-annual periods. Specifically, ocean currents with sub-monthly periods dominate the annual temporal variability of the ocean-induced magnetic field. Keywords. Electromagnetics (numerical methods) – geomagnetism and paleomagnetism (geomagnetic induction) – history of geophysics (transport)

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Rajput, P., R. Ramakrishnan, and A. S. Rajawat. "Retrieval of coastal ocean currents using MCC technique on satellite imagery for supplementing altimeter derived currents." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (December 23, 2014): 1483–89. http://dx.doi.org/10.5194/isprsarchives-xl-8-1483-2014.

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Maximum Cross Correlation (MCC) technique have been used to derive coastal currents from sequential OCM derived suspended sediment concentration (SSC) maps and the MCC currents are integrated with the Ocean surface current analysis-Real time (OSCAR) ocean currents along the coastal regions of the Southern India. OSCAR currents are mainly depended on the oceanographic measurements from the satellite altimeter which have limitations in the coastal region and in representing the mesoscale properties dominating the coastal ocean. Sequential pair of atmospherically corrected and georeferenced OCM image is used to derive SSC, along the southern coast of India. Maximum Cross-Correlation (MCC) method is applied on the sequential time lapsed images of OCM for matching the suspended sediment dispersion patterns. The MCC technique involves computing of cross-correlation coefficients and identifying correlation peaks. The spatial change of the sediment pattern occurs due to the advection by the currents and the extent of the change corresponds to the speed and direction of the current. From the first image, template window is selected, which is searched in the second image within large region defined as the search window. The movement of the SSC pattern is calculated based on the maximum cross correlation in successive images. Error statistics are calculated between the spatially coherent MCC vectors and OSCAR currents. Based on statistical analysis, an error threshold of 30 degree for current direction and 0.06m/sec for current speed was given to MCC currents and MCC currents beyond the error limit are rejected, while the MCC current within the error limit is merged with the OSCAR ocean currents. The merging of MCC currents has spatially enhanced the OSCAR currents. MCC method is significant in calculating the coastal currents and its mesoscale properties, which dominate the coastal surface flow field and can be used in supplementing the OSCAR ocean currents. Merging of both the currents, have effectively resulted in preparing contiguous maps of coastal ocean currents.

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Soebyakto, Soebyakto, Muhammad Yusuf, Muhammad Fajar Sidiq, and Rusnoto Rusnoto. "THE DETERMINATION OF OCEANOGRAPHIC PHYSICAL PROPERTIES AT THE COASTAL AREA OF TEGAL CITY." IJMS : Indonesian Journal of Mathematics and Natural Science 1, no. 1 (April 21, 2023): 32–42. http://dx.doi.org/10.61214/ijms.v1i1.36.

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Throughout our observations, the coastal area of Tegal has not been equipped with geological data and oceanographic data, especially the distribution of ocean current patterns around the coastal area of Tegal City. It is very important to know the nature of the pattern of ocean currents near the coast because the coastal area is for recreational activities and shipping activities to and from the port. The speed of ocean currents and where they are heading needs to be described so that the users of the coastal area can monitor well about the danger or not. In the study of the current pattern at the coastal area of Tegal City, the tool used was designed based on the Lagrangian method and the Helmholtz method to obtain the direction and magnitude of the ocean current's velocity. The problem in determining the current pattern is that the current signal is the result of various signals having a certain frequency generated by several different forces. The next problem in determining the height of the waves, the initial coordinate point is needed as the zero point. From this problem, researchers are interested in the current pattern that is formed. Ocean currents are the mass movement of seawater from one place to another, either vertically (upward motion) or horizontally. The purpose of this study finds the energy of ocean currents and the physical properties of oceanography near the coast, to get the level of danger if used for recreational areas, shipping activities, and research activities.

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Banihashemi, Saeideh, James T. Kirby, Fengyan Shi, and Zhifei Dong. "WAVES AND STRONGLY SHEARED CURRENTS: EXTENSIONS TO COASTAL OCEAN MODELS." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 40. http://dx.doi.org/10.9753/icce.v36.currents.40.

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Significant progress has been made in the numerical modeling of wave-current interaction during the past decade. Typical coastal circulation and wave models, however, still only employ theoretical formulations which take depth-uniform mean flows into account, with realistic, non-uniform flows treated as being depth uniform through some chosen averaging procedure. Depending on the choice of average over depth, significant errors may arise in the estimation of properties such as group velocity and action density in realistic conditions. These errors, in turn, are fed back into the circulation model through incorrect representation of the vertical structure of wave forcing. A new framework for wave-current interaction theory for strongly sheared mean flows has been developed using vortex force formalism by Dong (2016). The resulting formulation leads to a conservation law for wave action identical to that of Voronovich (1976), and to expressions for wave-averaged forces in the Craik-Leibovich vortex force formalism. In this study, we are completing the development of a coupled NHWAVE/SWAN which implements the wave forcing formulation of Dong (2016) in a wave-averaged version of the non-hydrostatic model NHWAVE (Ma et al., 2012). The SWAN model is also being extended to incorporate a better representation of frequency and direction-dependent group velocity and intrinsic frequency in the neighborhood of the spectral peak, thus improving on the present practice of using quantities evaluated only at the spectral peak. The resulting model is being tested against field data collected in several recent experiments involving strong, vertically sheared currents in river mouths or straits.

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Hsin, Yi-Chia. "Trends of the Pathways and Intensities of Surface Equatorial Current System in the North Pacific Ocean." Journal of Climate 29, no. 18 (August 31, 2016): 6693–710. http://dx.doi.org/10.1175/jcli-d-15-0850.1.

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Abstract An ensemble of ocean reanalysis products is utilized to quantify the long-term tendencies of pathways and along-pathway transports of the three surface equatorial currents (North Equatorial Current, North Equatorial Countercurrent, and northern branch of the South Equatorial Current) in the North Pacific Ocean during the period of the 1900s–2000s. This study uses 12 ocean reanalysis products in the ensemble for the period after the 1960s, while only 2 Simple Ocean Data Assimilation (SODA) products are taken into consideration for the period prior to 1960s. The analyses indicate that the three currents in the western (eastern) Pacific Ocean have more southern (northern) mean central positions and tend to move southward (northward) over the past 100 years. All three currents have weakening tendencies, with the exception of the North Equatorial Current having intensified in the western Pacific Ocean. The Sverdrup dynamics, which directly relates the wind-driven circulation in the interior ocean to wind stress curl and Earth rotation, can be applied to simply address the long-term changes of intensities and pathways of the three surface currents in the tropical North Pacific Ocean.

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Brown, J., C. A. Clayson, L. Kantha, and T. Rojsiraphisal. "North Indian Ocean variability during the Indian Ocean dipole." Ocean Science Discussions 5, no. 2 (June 9, 2008): 213–53. http://dx.doi.org/10.5194/osd-5-213-2008.

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Abstract. The circulation in the North Indian Ocean (NIO henceforth) is highly seasonally variable. Periodically reversing monsoon winds (southwesterly during summer and northeasterly during winter) give rise to seasonally reversing current systems off the coast of Somalia and India. In addition to this annual monsoon cycle, the NIO circulation varies semiannually because of equatorial currents reversing four times each year. These descriptions are typical, but how does the NIO circulation behave during anomalous years, during an Indian Ocean dipole (IOD) for instance? Unfortunately, in situ observational data are rather sparse and reliance has to be placed on numerical models to understand this variability. In this paper, we estimate the surface current variability from a 12-year hindcast of the NIO for 1993–2004 using a 1/2° resolution circulation model that assimilates both altimetric sea surface height anomalies and sea surface temperature. Presented in this paper is an examination of surface currents in the NIO basin during the IOD. During the non-IOD period of 2000–2004, the typical equatorial circulation of the NIO reverses four times each year and transports water across the basin preventing a large sea surface temperature difference between the western and eastern NIO. Conversely, IOD years are noted for strong easterly and westerly wind outbursts along the equator. The impact of these outbursts on the NIO circulation is to reverse the direction of the currents – when compared to non-IOD years – during the summer for negative IOD events (1996 and 1998) and during the fall for positive IOD events (1994 and 1997). This reversal of current direction leads to large temperature differences between the western and eastern NIO.

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Mishra, Anshu Prakash, S. Rai, and A. C. Pandey. "Ocean Model Simulation of Southern Indian Ocean Surface Currents." Marine Geodesy 30, no. 4 (November 7, 2007): 345–54. http://dx.doi.org/10.1080/01490410701568467.

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Chen, Ziming, Jinjin Yan, Ruen Huang, Yisong Gao, Xiuyan Peng, and Weijie Yuan. "Path Planning for Autonomous Underwater Vehicles (AUVs) Considering the Influences and Constraints of Ocean Currents." Drones 8, no. 8 (July 26, 2024): 348. http://dx.doi.org/10.3390/drones8080348.

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Ocean currents pose a significant challenge in the path planning of autonomous underwater vehicles (AUVs), with conventional path-planning algorithms often failing to effectively counter these influences. In response to this challenge, we propose a path-planning algorithm that can consider the influences and constraints of ocean currents, which leverages the strengths of two widely employed path-planning algorithms, A* and the genetic algorithm (GA), to account for the influences of ocean currents on the planned paths. Specifically, it enhances the initial population generation, formulates a fitness function tailored to ocean current conditions, and employs an adaptive mutation approach to enhance population diversity and stability. By utilizing simulated and real-world ocean current datasets, we validated the feasibility of the proposed algorithm with quantitative metrics. The results demonstrate that in comparison to conventional methods, the new algorithm can deal with the influences and constraints of ocean currents in AUV path planning, resulting in notable enhancements in path smoothness, energy efficiency, and safety.

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Anisa, Nur, Mario Putra Suhana, and Harish Wirayuhanto. "Pemodelan Hidrodinamika 2-Dimensi Arus Laut Permukaan Perairan Desa Berakit Kabupaten Bintan." Rekayasa 16, no. 2 (August 12, 2023): 148–55. http://dx.doi.org/10.21107/rekayasa.v16i2.17227.

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Information related to ocean currents is not yet available in Berakit Village waters, ocean currents are an important parameter to determine the condition of a waters. An alternative that can be used to determine the condition of ocean currents is to use hydrodynamic modeling. The purpose of the study was to analyze the distribution pattern and characteristics of surface ocean currents. This research was conducted by conducting 2-dimensional hydrodynamic modeling simulating ocean currents for 1 (one) year in December 2020-November 2021 using MIKE 21 software by sampling in 6 (six) different conditions, namely at the highest tide, lowest tide, high tide. towards the ebb and flow of the full moon, the ebb towards the negligible tide, the tide towards the ebb tide and the ebb towards the negligible tide. The model results were validated by the RMSE formula with a value of 2%, the model results were very good, so that they could be used as a reference in providing an overview of the real conditions of the pattern and current distribution at the research location. The movement of ocean currents at the time of the full moon and negligible dominant currents move towards the south of the waters, while at the time of the full tide and negligible the dominant currents move towards the north of the waters. In the north season, the current velocity ranges from 0.00006 m/s-0.125 m/s with the dominant movement towards the north. East monsoon currents move predominantly north and south with speeds ranging from 0.0000003 m/s-0.129 m/s. In the south monsoon the dominant current moves to the north and south at a speed of 0.0000007 m/s-0.13 m/s. in the west season, the dominant current moves to the north and south at a speed of 0.00001 m/s-0.12 m/s. The speed of the dominant ocean currents is greater at high tide compared to low tide, this is due to differences in sea level elevation in the opposite direction of motion.

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Zhao, Xi, Benlong Wang, and Hua Liu. "PROPAGATION AND RUNUP OF TSUNAMI WAVES WITH BOUSSINESQ MODEL." Coastal Engineering Proceedings 1, no. 32 (January 30, 2011): 9. http://dx.doi.org/10.9753/icce.v32.currents.9.

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With certain profiles of bottom movements, orders of wave height of submarine earthquake-induced tsunami both in deep ocean and nearshore area have been studied using the Boussinesq equations. An earthquake of large magnitude generates a typical N-wave which can propagate long distance in open ocean without deformation. Since the magnitude and length of tsunami waves related to vertical and horizontal scale of geological movements, solitary wave and N-wave are extended to waves not tied to solitary property which represent tsunami waves better. In a horizontal one dimensional numerical wave flume, runup of solitary wave, N-wave, single crest and N-wave composed by a single crest and a single trough on a slope beach have been simulated. The results fit analytical solutions of nonlinear shallow water equations well. The Indian Ocean tsunami has been simulated with the horizontal two dimensional high order Boussinesq model. Comparison between numerical results and measured data from field survey validates the numerical model.

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Makkulau, Andi, Samsurizal Samsurizal, Miftahul Fikri, and Chesya Rusiana. "Perancangan Vertical Axis Twin Turbine Pada Pembangkit Listrik Arus Laut Di Suramadu." SUTET 12, no. 2 (January 1, 2023): 86–97. http://dx.doi.org/10.33322/sutet.v12i2.1670.

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Renewable energy sources are environmentally friendly energy sources that do not pollute the environment and do not contribute to climate change and global warming as in other traditional sources. Ocean currents are the movement of seawater masses from one place to another either vertically (upward motion) or horizontally (sideways movement) towards equilibrium, or the very wide movement of water that occurs throughout the world's oceans. In this study using experimental research where the maximum ocean current speed results in pile 56 were only 1.28 m / s, the turbine will need a greater speed to beat the initial torque of the 5 kW generator. The results of the 12-day test showed that the speed of the ocean current at Suramadu Bridge pile 56 ranged from 0 - 70 cm/s and only 1 week with a maximum ocean current speed, which was 128 cm/s. When using a 5 kW generator, it is likely that the generator will rotate and generate electric current for only a week. Beyond that the generator does not rotate because the speed of the ocean current is low. Therefore, the condition that the initial torque is obviously smaller than 10 kW in the twin turbines installed 3 generators each are 3.5 kW so that the turbine is still able to rotate at low current speeds such as the speed of ocean currents in Suramadu and generally Indonesian waters.

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32

Corela, Carlos, Afonso Loureiro, José Luis Duarte, Luis Matias, Tiago Rebelo, and Tiago Bartolomeu. "The effect of deep ocean currents on ocean- bottom seismometers records." Natural Hazards and Earth System Sciences 23, no. 4 (April 20, 2023): 1433–51. http://dx.doi.org/10.5194/nhess-23-1433-2023.

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Abstract. Ocean-bottom seismometers (OBSs) are usually deployed for seismological investigations, but these objectives are impaired by noise resulting from the ocean environment. We split the OBS-recorded seismic noise into three bands: short periods, microseisms and long periods, also known as tilt noise. We show that bottom currents control the first and third bands, but these are not always a function of the tidal forcing. Instead, we suggest that the ocean bottom has a flow regime resulting from two possible contributions: the permanent low-frequency bottom current and the tidal current. The recorded noise displays the balance between these currents along the entire tidal cycle, between neap and spring tides. In the short-period noise band, the ocean current generates harmonic tremors corrupting seismic dataset records. We show that, in the investigated cases, the harmonic tremors result from the interaction between the ocean current and mechanical elements of the OBS that are not essential during the sea bottom recording and thus have no geological origin. The data from a new broadband OBS type, designed and built at Instituto Dom Luiz (IDL – University of Lisbon)/Centre of Engineering and Product Development (CEIIA), hiding non-essential components from the current flow, show how utmost harmonic noise can be eliminated.

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33

Isern-Fontanet, Jordi, Joaquim Ballabrera-Poy, Antonio Turiel, and Emilio García-Ladona. "Remote sensing of ocean surface currents: a review of what is being observed and what is being assimilated." Nonlinear Processes in Geophysics 24, no. 4 (October 17, 2017): 613–43. http://dx.doi.org/10.5194/npg-24-613-2017.

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Abstract. Ocean currents play a key role in Earth's climate – they impact almost any process taking place in the ocean and are of major importance for navigation and human activities at sea. Nevertheless, their observation and forecasting are still difficult. First, no observing system is able to provide direct measurements of global ocean currents on synoptic scales. Consequently, it has been necessary to use sea surface height and sea surface temperature measurements and refer to dynamical frameworks to derive the velocity field. Second, the assimilation of the velocity field into numerical models of ocean circulation is difficult mainly due to lack of data. Recent experiments that assimilate coastal-based radar data have shown that ocean currents will contribute to increasing the forecast skill of surface currents, but require application in multidata assimilation approaches to better identify the thermohaline structure of the ocean. In this paper we review the current knowledge in these fields and provide a global and systematic view of the technologies to retrieve ocean velocities in the upper ocean and the available approaches to assimilate this information into ocean models.

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Cunningham, Stuart A. "Southern Ocean circulation." Archives of Natural History 32, no. 2 (October 2005): 265–80. http://dx.doi.org/10.3366/anh.2005.32.2.265.

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The Discovery Investigations of the 1930s provided a compelling description of the main elements of the Southern Ocean circulation. Over the intervening years, this has been extended to include ideas on ocean dynamics based on physical principles. In the modern description, the Southern Ocean has two main circulations that are intimately linked: a zonal (west-east) circumpolar circulation and a meridional (north-south) overturning circulation. The Antarctic Circumpolar Current transports around 140 million cubic metres per second west to east around Antarctica. This zonal circulation connects the Atlantic, Indian and Pacific Oceans, transferring and blending water masses and properties from one ocean basin to another. For the meridional circulation, a key feature is the ascent of waters from depths of around 2,000 metres north of the Antarctic Circumpolar Current to the surface south of the Current. In so doing, this circulation connects deep ocean layers directly to the atmosphere. The circumpolar zonal currents are not stable: meanders grow and separate, creating eddies and these eddies are critical to the dynamics of the Southern Ocean, linking the zonal circumpolar and meridional circulations. As a result of this connection, a global three-dimensional ocean circulation exists in which the Southern Ocean plays a central role in regulating the Earth's climate.

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35

Shinoda, Toshiaki, Weiqing Han, E. Joseph Metzger, and Harley E. Hurlburt. "Seasonal Variation of the Indonesian Throughflow in Makassar Strait." Journal of Physical Oceanography 42, no. 7 (July 1, 2012): 1099–123. http://dx.doi.org/10.1175/jpo-d-11-0120.1.

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Abstract The seasonal variation of Indonesian Throughflow (ITF) transport is investigated using ocean general circulation model experiments with the Hybrid Coordinate Ocean Model (HYCOM). Twenty-eight years (1981–2008) of ⅓° Indo-Pacific basin HYCOM simulations and three years (2004–06) from a global HYCOM simulation are analyzed. Both models are able to simulate the seasonal variation of upper-ocean currents and the total transport through Makassar Strait measured by International Nusantara Stratification and Transport (INSTANT) moorings reasonably well. The annual cycle of upper-ocean currents is then calculated from the Indo-Pacific HYCOM simulation. The reduction of southward currents at Makassar Strait during April–May and October–November is evident, consistent with the INSTANT observations. Analysis of the upper-ocean currents suggests that the reduction in ITF transport during April–May and October–November results from the wind variation in the tropical Indian Ocean through the generation of a Wyrtki jet and the propagation of coastal Kelvin waves, while the subsequent recovery during January–March originates from upper-ocean variability associated with annual Rossby waves in the Pacific that are enhanced by western Pacific winds. These processes are also found in the global HYCOM simulation during the period of the INSTANT observations. The model experiments forced with annual-mean climatological wind stress in the Pacific and 3-day mean wind stress in the Indian Ocean show the reduction of southward currents at Makassar Strait during October–November but no subsequent recovery during January–March, confirming the relative importance of wind variations in the Pacific and Indian Oceans for the ITF transport in each season.

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You, Zai Jin, Peter Nielsen, David Hanslow, and Tim Pritchard. "ELEVATED WATER LEVELS AT TRAINED RIVER ENTRANCES." Coastal Engineering Proceedings 1, no. 33 (December 14, 2012): 48. http://dx.doi.org/10.9753/icce.v33.currents.48.

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The south-east coast of Australia has many low-lying areas at river entrances that are vulnerable to coastal inundation due to high water levels elevated by ocean tides, coastal storms, ocean waves and other drivers. The penetration of elevated entrance water levels into rivers can further intensify river flooding associated with high rainfall events. In this study, historical water level data, which were collected continuously at 17 inshore and 5 offshore permanent tide stations along the East Coast of Australia, are used to study effects of tides and waves on water levels at trained river entrances and also to estimate extreme entrance water levels without major entrance rainfall-related flooding.

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Chang, Yu-Chia, Ruo-Shan Tseng, Guan-Yu Chen, Peter C. Chu, and Yung-Ting Shen. "Ship Routing Utilizing Strong Ocean Currents." Journal of Navigation 66, no. 6 (July 17, 2013): 825–35. http://dx.doi.org/10.1017/s0373463313000441.

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From the Surface Velocity Program (SVP) drifter current data, a detailed and complete track of strong ocean currents in the north-western Pacific is provided using the bin average method. The focus of this study is on the Kuroshio, the strong western boundary current of the North Pacific flowing northward along the east coast of Taiwan and then turning eastward off southern Japan. With its average flow speed of about 2 knots, the Kuroshio can significantly increase the ship's speed for a “super-slow-steaming” container ship travelling at speeds of 12 knots between the ports of Southeast Asia and Japan. By properly utilizing knowledge of strong ocean currents to follow the Kuroshio on the northbound runs and avoid it on the return trip, considerable fuel can be saved and the transit time can be reduced. In the future, the detailed Kuroshio saving-energy route could be built into electronic chart systems for all navigators and shipping routers.

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Abdolali, Ali, and James T. Kirby. "TSUNAMI PHASE SPEED REDUCTION DUE TO WATER COMPRESSIBILTY." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 9. http://dx.doi.org/10.9753/icce.v36.currents.9.

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Most existing tsunami propagation models consider the ocean to be an incompressible, homogenous medium. Recently, it has been shown that a number of physical features can slow the propagation speed of tsunami waves, including wave frequency dispersion, ocean bottom elasticity, water compressibility and thermal or salinity stratification. These physical effects are secondary to the leading order, shallow water or long wave behavior, but still play a quantifiable role in tsunami arrival time, especially at far distant locations. In this work, we have performed analytical and numerical investigations and have shown that consideration of those effects can actually improve the prediction of arrival time at distant stations, compared to incompressible forms of wave equations. We derive a modified Mild Slope Equation for Weakly Compressible fluid following the method proposed by Sammarco et al. (2013) and Abdolali et al. (2015) using linearized wave theory, and then describe comparable extensions to the Boussinesq model of Kirby et al. (2013). Both models account for water compressibility and compression of static water column to simulate tsunami waves. The mild slope model is formulated in plane Cartesian coordinates and is thus limited to medium propagation distances, while the Boussinesq model is formulated in spherical polar coordinates and is suitable for ocean scale simulations.

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39

Dohan, Kathleen, and Nikolai Maximenko. "Monitoring Ocean Currents with Satellite Sensors." Oceanography 23, no. 4 (December 1, 2010): 94–103. http://dx.doi.org/10.5670/oceanog.2010.08.

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40

Kamenkovich, Igor V., and Joseph Pedlosky. "Radiating Instability of Nonzonal Ocean Currents." Journal of Physical Oceanography 26, no. 4 (April 1996): 622–43. http://dx.doi.org/10.1175/1520-0485(1996)026<0622:rionoc>2.0.co;2.

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41

Chave, Alan D., Jean H. Filloux, and Douglas S. Luther. "Electromagnetic induction by ocean currents: BEMPEX." Physics of the Earth and Planetary Interiors 53, no. 3-4 (March 1989): 350–59. http://dx.doi.org/10.1016/0031-9201(89)90021-6.

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42

Dohan, Kathleen. "Ocean surface currents from satellite data." Journal of Geophysical Research: Oceans 122, no. 4 (April 2017): 2647–51. http://dx.doi.org/10.1002/2017jc012961.

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43

Deng, Zengan, Lian Xie, Bin Liu, Kejian Wu, Dongliang Zhao, and Ting Yu. "Coupling winds to ocean surface currents over the global ocean." Ocean Modelling 29, no. 4 (January 2009): 261–68. http://dx.doi.org/10.1016/j.ocemod.2009.05.003.

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44

Liu, Jianfei, William J. Emery, Xiongbin Wu, Miao Li, Chuan Li, and Lan Zhang. "Computing Ocean Surface Currents From GOCI Ocean Color Satellite Imagery." IEEE Transactions on Geoscience and Remote Sensing 55, no. 12 (December 2017): 7113–25. http://dx.doi.org/10.1109/tgrs.2017.2741924.

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45

Wang, Tianyu, Yan Du, and Minyang Wang. "Overlooked Current Estimation Biases Arising from the Lagrangian Argo Trajectory Derivation Method." Journal of Physical Oceanography 52, no. 1 (January 2022): 3–19. http://dx.doi.org/10.1175/jpo-d-20-0287.1.

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Abstract An Argo simulation system is used to provide synthetic Lagrangian trajectories based on the Estimating the Circulation and Climate of the Ocean Model, phase II (ECCO2). In combination with ambient Eulerian velocity at the reference layer (1000 m) from the model, quantitative metrics of the Lagrangian trajectory–derived velocities are computed. The result indicates that the biases induced by the derivation algorithm are strongly linked with ocean dynamics. In low latitudes, Ekman currents and vertically sheared geostrophic currents influence both the magnitude and the direction of the derivation velocity vectors. The maximal shear-induced biases exist near the equator with the amplitudes reaching up to about 1.2 cm s−1. The angles of the shear biases are pronounced in the low-latitude oceans, ranging from −8° to 8°. Specifically, the study shows an overlooked bias from the float drifting motions that mainly occurs in the western boundary current and Antarctic Circumpolar Current (ACC) regions. In these regions, a recently reported horizontal acceleration measured via Lagrangian floats is significantly associated with the strong eddy–jet interactions. The acceleration could induce an overestimation of Eulerian current velocity magnitudes. For the common Argo floats with a 9-day float parking period, the derivation speed biases induced by velocity acceleration would be as large as 3 cm s−1, approximately 12% of the ambient velocity. It might have implications to map the mean middepth ocean currents from Argo trajectories, as well as to understand the dynamics of eddy–jet interactions in the ocean.

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46

Lee, Han Soo, Takao Yamashita, Tomoaki Komaguchi, and Toyoaki Mishima. "STORM SURGE IN SETO INLAND SEA WITH CONSIDERATION OF THE IMPACTS OF WAVE BREAKING ON SURFACE CURRENTS." Coastal Engineering Proceedings 1, no. 32 (January 29, 2011): 17. http://dx.doi.org/10.9753/icce.v32.currents.17.

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Storm surge and storm wave simulations in Seto Inland Sea (SIS) in Japan were conducted for Typhoon Yancy (9313) and Chaba (0416) using an atmosphere (MM5)-wave (SWAN)-ocean (POM) modeling system. In the coupled modeling system, a new method for wave-current interaction in terms of momentum transfer due to whitecapping in deep water and depth-induced wave breaking in shallow water was considered. The calculated meteorological and wave fields show good agreement with the observations in SIS and its vicinities. The storm surge results also exhibit good accordance with the observations in SIS. To resolve a number of islands in SIS, we also performed numerical experiments with different grid resolutions and obtained improved results from higher resolutions in wave and ocean circulation fields.

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Nakamura, Ryota, Martin MÃ¤ll, Tomoya Shibayama, and Shigeru Kato. "INTER-COMPARISON OF COASTAL MODELS: CASE STUDY OF STORM SURGE AT NEMURO IN JAPAN." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 79. http://dx.doi.org/10.9753/icce.v36.currents.79.

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The numerical coastal circulation models play an essential role in predicting storm surges. Several models (e.g. ADCIRC: Dietrich et al., 2004, FVCOM: Chen et al., 2003) have been previously inter-compared (Kerr et al., 2013; Chen et al., 2013). In these studies, storm surges were reproduced in locations where the bathymetry has a gradual increase from offshore to coast, within a closed gulf. On the other hand, there are few studies in regards to modelling storm surge where the near coast bathymetry is steep and connected to open ocean. Considering the storm surge dependence on local bathymetry, it can be important to conduct an inter-comparison of ocean circulation models in such a region. In this study, numerical coastal circulation models (2D-ADCIRC and 3D-FVCOM) are compared by using a 2014 Dec. storm surge event at Nemuro city in Hokkaido (Japan), which was caused by a rapidly intensified extra-tropical cyclone approaching the area. In this region, local bathymetry is steep due to Japan Trench. The cyclone caused a storm surge of nearly up to 1.8 m within the Nemuro city between 00:00 UTC 16th and 17th Dec. 2014. The aim of this study is to evaluate the performance of ocean circulation models using several air-sea drag coefficients and contribute to inter-comparison studies using ADCIRC and FVCOM.

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Yan, Changxiang, and Jiang Zhu. "Evaluation of an Ocean Reanalysis System in the Indian and Pacific Oceans." Atmosphere 14, no. 2 (January 20, 2023): 220. http://dx.doi.org/10.3390/atmos14020220.

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This paper describes an ocean reanalysis system in the Indian and Pacific oceans (IPORA) and evaluates its quality in detail. The assimilation schemes based on ensemble optimal interpolation are employed in the hybrid coordinate ocean model to conduct a long-time reanalysis experiment during the period of 1993–2020. Different metrics including comparisons with satellite sea surface temperature, altimetry data, observed currents, as well as other reanalyses such as ECCO and SODA are used to validate the performance of IPORA. Compared with the control experiment without assimilation, IPORA greatly reduces the errors of temperature, salinity, sea level anomaly, and current fields, and improves the interannual variability. In contrast to ECCO and SODA products, IPORA captures the strong signals of SLA variability and reproduces the linear trend of SLA very well. Meanwhile, IPORA also shows a good consistence with observed currents, as indicated by an improved correlation and a reduced error.

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Huang, Yongjiang, Xixiang Liu, Qiantong Shao, and Zixuan Wang. "Virtual Metrology Filter-Based Algorithms for Estimating Constant Ocean Current Velocity." Remote Sensing 15, no. 16 (August 20, 2023): 4097. http://dx.doi.org/10.3390/rs15164097.

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The strap-down inertial navigation system (SINS) and Doppler velocity log (DVL) integrated navigation system are widely used for autonomous underwater vehicles (AUVs). Whereas DVL works in the water tracking mode, the velocity provided by DVL is relative to the current layer and cannot be directly used to suppress the divergence of SINS errors. Therefore, the estimation and compensation of the ocean current velocity play an essential role in improving navigation positioning accuracy. In recent works, ocean currents are considered constant over a short term in small areas. In the common KF algorithm with the ocean current as a state vector, the current velocity cannot be estimated because the current velocity and the SINS velocity error are coupled. In this paper, two virtual metrology filter (VMF) methods are proposed for estimating the velocity of ocean currents based on the properties that the currents remain unchanged at the adjacent moments. New measurement equations are constructed to decouple the current velocity and the SINS velocity error, respectively. Simulations and lake tests show that both proposed methods are effective in estimating the current velocity, and each has its advantages in estimating the ocean current velocity or the misalignment angle.

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Knutsen, Halvor, Per Erik Jorde, Ole Thomas Albert, A. Rus Hoelzel, and Nils Chr Stenseth. "Population genetic structure in the North Atlantic Greenland halibut (Reinhardtius hippoglossoides): influenced by oceanic current systems?" Canadian Journal of Fisheries and Aquatic Sciences 64, no. 6 (June 29, 2007): 857–66. http://dx.doi.org/10.1139/f07-070.

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We report statistically significant genetic structure among samples of Greenland halibut (Reinhardtius hippoglossoides), rejecting the null hypothesis of panmixia in the North Atlantic. The species appears instead to be subdivided into partially isolated populations, with some evidence for isolation by distance. However, there is a dichotomy between transatlantic sample comparisons and those within a regional current system, even when geographic distance is similar. Calculating geographic distance along the flow of ocean currents gave a more linear correlation with genetic differentiation than straight-line geographic distances, suggesting that gene flow follows ocean currents. We hypothesize that gene flow is mediated by drift of eggs and larvae with ocean currents, a hypothesis that is consistent with the extended pelagic phase of Greenland halibut larvae. This implies an important role for ocean currents in shaping the genetic structure of this and potentially other deep-sea species.

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Journal articles on the topic 'Ocean currents'

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