Journal articles: 'Rip currents'

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Dalrymple, Robert A., Jamie H. MacMahan, Ad J. H. M. Reniers, and Varjola Nelko. "Rip Currents." Annual Review of Fluid Mechanics 43, no. 1 (January 21, 2011): 551–81. http://dx.doi.org/10.1146/annurev-fluid-122109-160733.

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Choi, Junwoo, Sung-Bum Yoon, Jimin Ko, and Tae-Soon Kang. "PERFORMANCES OF THE RIP CURRENT WARNING SYSTEM AT THE HAEUNDAE COAST OF SOUTH KOREA." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 20. http://dx.doi.org/10.9753/icce.v36.currents.20.

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Haeundae is one of the most beautiful beaches in Korea, and is also notorious for frequent and strong rip currents. Every recent year in this beach, hundreds of swimmers rescued from rip currents have been reported. The large-scale Haeundae rip current is known to be a kind of transient rip currents which is hardly predicted. The successive ends of wave-crest pattern (i.e., honeycomb wave-crest pattern(Dalrymple et al., 2011)), which generate rip current, are mainly formed by two-directional wave trains due to the refraction of incident swells over submerged shoals and ridges of the Haeundae coast. Many people are caught by the rip current in the relatively calm sea and weather conditions. The incident waves generating rip currents are nearly monochromatic with the wave period of 7-13 seconds. These swells are supposed to be generated by distant typhoons formed in the Philippine Sea. Some of them might propagate with dispersion and dissipation during the travel toward the south coast of the Korean Peninsula, especially to the Haeundae coast. In order to protect the swimmers from the rip current accidents, Choi et al. (2014) proposed a method for a rip current warning system, and Korea Hydrographic and Oceanographic Administration (KHOA) has established and operated the rip current warning system to the Haeundae beach. The rip current warning system estimates the rip current risk level based on the real-time incident wave conditions measured near the beach and the database pre-calculated by a numerical model according to various wave and tide conditions and the topography of the Haeundae coast. The Boussinesq wave model, FUNWAVE (Wei et al., 1999; Choi et al., 2015) was utilized for resolving the ends of the wave crests. This study showed the performance of the forecast and warning system of the rip current at the Haeundae coast of South Korea.

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Winter, Gundula, Ap Van Dongeren, Matthieu De Schipper, and Jaap Van Thiel de Vries. "A FIELD AND NUMERICAL STUDY INTO RIP CURRENTS IN WIND-SEA DOMINATED ENVIRONMENTS." Coastal Engineering Proceedings 1, no. 33 (October 25, 2012): 36. http://dx.doi.org/10.9753/icce.v33.currents.36.

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Rip currents are wave-induced and off-shore directed flows which occur frequently in the surf zone and can pose a serious threat to swimmers. While the behaviour of rip currents has been studied in swell-dominated environments, less is known about their characteristics in wind-sea dominated environments. This study aims to improve the knowledge on rip currents in these environments such as the Dutch coast. In a field campaign at Egmond aan Zee (The Netherlands), Lagrangian velocities in the surf zone were measured with drifter floats. An extensive dataset of rip current measurements was collected from which parameters that initiate rip currents and affect their mean flow properties were identified. Numerical simulations with XBeach aided to understand and confirm the observations made in the field. A reduction of the hydrodynamic parameters along with simplification of the bathymetry in the model allowed for identification of the governing rip current parameters, which can be the basis for a warning system.

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Pitman, Sebastian J., Katie Thompson, Deirdre E. Hart, Kevin Moran, Shari L. Gallop, Robert W. Brander, and Adam Wooler. "Beachgoers' ability to identify rip currents at a beach in situ." Natural Hazards and Earth System Sciences 21, no. 1 (January 14, 2021): 115–28. http://dx.doi.org/10.5194/nhess-21-115-2021.

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Abstract. Rip currents (“rips”) are the leading cause of drowning on surf beaches worldwide. A major contributing factor is that many beachgoers are unable to identify rip currents. Previous research has attempted to quantify beachgoers' rip identification ability using photographs of rip currents without identifying whether this usefully translates into an ability to identify a rip current in situ at the beach. This study is the first to compare beachgoers ability to identify rip currents in photographs and in situ at a beach in New Zealand (Muriwai Beach) where a channel rip current was present. Only 22 % of respondents were able to identify the in situ rip current. The highest rates of success were for males (33 %), New Zealand residents (25 %), and local beach users (29 %). Of all respondents who were successful at identifying the rip current in situ, 62 % were active surfers/bodyboarders, and 28 % were active beach swimmers. Of the respondents who were able to identify a rip current in two photographs, only 34 % were able to translate this into a successful in situ rip identification, which suggests that the ability to identify rip currents by beachgoers is worse than reported by previous studies involving photographs. This study highlights the difficulty of successfully identifying a rip current in reality and that photographs are not necessarily a useful means of teaching individuals to identify rip currents. It advocates for the use of more immersive and realistic education strategies, such as the use of virtual reality headsets showing moving imagery (videos) of rip currents in order to improve rip identification ability.

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Choi, Junwoo, Min Roh, and Hyung-sik Hwang. "LABORATORY MODEL TEST OF TRANSIENT RIP CURRENTS DUE TO PSEUDO HONEYCOMB PATTERN WAVES." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 19. http://dx.doi.org/10.9753/icce.v36.currents.19.

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The Haeundae coast of South Korea is famous for its beautiful beach, but the rip current, from which the beach-guards rescue more than 100 people every summer at the beach, is now a notorious phenomenon. The large-scale Haeundae rip current is known to be a transient rip current caused by multi-directional wave trains rather than the topography-induced rip current, for example, due to a gap of sandbar. In other words, the rip current seems develop along the cross-shore nodal line area in the honeycomb wave-crest pattern (Dalrymple et al., 2011) which are generated in a shallow water when two wave trains propagate with slightly different wave directions (i.e., interference pattern). The wave pattern is formed by the refraction of incident swells over submerged shoals and ridges of the Haeundae coast. The Haeundae rip current is an example explained by the vortex generation due to the ends of wave crests in Peregrine(1998), which is known of the basic generation mechanism of rip currents(Johnson and Pattiaratchi, 2006; Clark et al., 2012; Feddersen, 2014). To understand the generation mechanism and verify the numerical model results of the Haeundae rip current, the laboratory experiment was planned. This study showed the preliminary laboratory observations which include the pseudo honeycomb pattern of incident waves and its resultant rip current.

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Marshall, David P., Bendix Vogel, and Xiaoming Zhai. "Rossby rip currents." Geophysical Research Letters 40, no. 16 (August 20, 2013): 4333–37. http://dx.doi.org/10.1002/grl.50842.

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Ruju, Andrea, Pablo Higuera, Javier L. Lara, Inigo J. Losada, and Giovanni Coco. "RIP CURRENTS ON A BARRED BEACH." Coastal Engineering Proceedings 1, no. 33 (December 14, 2012): 38. http://dx.doi.org/10.9753/icce.v33.currents.38.

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This work presents the numerical study of rip current circulation on a barred beach. The numerical simulations have been carried out with the IH-FOAM model which is based on the three dimensional Reynolds Averaged Navier-Stokes equations. The new boundary conditions implemented in IH-FOAM have been used, including three dimensional wave generation as well as active wave absorption at the boundary. Applying the specific wave generation boundary conditions, the model is validated to simulate rip circulation on a barred beach. Moreover, this study addresses the identification of the forcing mechanisms and the three dimensional structure of the mean flow.

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Drozdzewski, D., W. Shaw, D. Dominey-Howes, R. Brander, T. Walton, A. Gero, S. Sherker, J. Goff, and B. Edwick. "Surveying rip current survivors: preliminary insights into the experiences of being caught in rip currents." Natural Hazards and Earth System Sciences 12, no. 4 (April 26, 2012): 1201–11. http://dx.doi.org/10.5194/nhess-12-1201-2012.

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Abstract. This paper begins a process of addressing a significant gap in knowledge about people's responses to being caught in rip currents. While rip currents are the primary hazard facing recreational ocean swimmers in Australia, debate exists about the best advice to give swimmers caught in rip currents. Such surf rescue advice – on what to do and how to respond when caught in a rip – relies on empirical evidence. However, at present, knowledge about swimmers reactions and responses to rip currents is limited. This gap is a considerable barrier to providing effective advice to beach goers and to understanding how this advice is utilised (or not) when actually caught in the rip current. This paper reports the findings of a pilot study that focussed on garnering a better understanding of swimmers' experiences when caught in rip currents. A large scale questionnaire survey instrument generated data about rip current survivors' demographics, knowledge of beach safety and their reactions and responses when caught in a rip current. A mix of online and paper surveys produced a total of 671 completed surveys. Respondents were predominantly an informed group in terms of rip current knowledge, beach experience and had a high self-rated swimming ability. Preliminary insights from the survey show that most respondents recalled a "swim across the rip/parallel to the beach" message when caught in the rip and most escaped unassisted by acting on this message. However, while nearly a quarter of respondents recalled a message of "not to panic", short answer responses revealed that the onset of panic inhibited some respondents from recalling or enacting any other type of beach safety message when caught in the rip current. Results also showed that despite the research sample being younger, competent and frequent ocean swimmers, they were more likely to swim at unpatrolled beaches and outside of the red and yellow safety flags. Moreover, they were still caught in a rip current and they panicked. The findings of this study have significant implications for a range of demographic groups of differing beach safety knowledge and swimming ability who may be caught in rip currents behave, we know very little about how beach goers may respond to being caught in them.

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Jalali Farahani, Rozita, Robert A. Dalrymple, Alexis Hérault, and Giuseppe Bilotta. "SPH MODELING OF MEAN VELOCITY CIRCULATION IN A RIP CURRENT SYSTEM." Coastal Engineering Proceedings 1, no. 33 (December 14, 2012): 37. http://dx.doi.org/10.9753/icce.v33.currents.37.

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A Lagrangian numerical model called Smoothed Particle Hydrodynamics is used to analyze rip current system generated by a single bar and a rip channel. The pattern of the wave-induced circulation cell over the bar, the oppositely-rotating circulation cell on-shore and a strong seaward-directed current in the rip channel is modeled numerically. The mean horizontal variations of rip current system as well as three-dimensional circulations are studied. The results in three-dimensional space reveal the wave-current interaction and flow patterns in different parts of rip channel, bar, and the trough located near shore. For comparison to experimental data, Eulerian nodes are introduced to the numerical model and SPH interpolation over neighboring Lagrangian particles is implemented to find fluid parameters at those specific nodes. This methodology leads to a better understanding of depth-integrated flows and a more accurate comparison of numerical results with experimental results. Model predictions are compared to laboratory measurements of Drønen et al. (2002) and show good agreement, including mean velocity profiles, mean surface elevation and three-dimensional velocity components.

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HALLER, MERRICK C., and R. A. DALRYMPLE. "Rip current instabilities." Journal of Fluid Mechanics 433 (April 25, 2001): 161–92. http://dx.doi.org/10.1017/s0022112000003414.

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A laboratory experiment involving rip currents generated on a barred beach with periodic rip channels indicates that rip currents contain energetic low-frequency oscillations in the presence of steady wave forcing. An analytic model for the time-averaged flow in a rip current is presented and its linear stability characteristics are investigated to evaluate whether the rip current oscillations can be explained by a jet instability mechanism. The instability model considers spatially growing disturbances in an offshore directed, shallow water jet. The effects of variable cross-shore bathymetry, non-parallel flow, turbulent mixing, and bottom friction are included in the model. Model results show that rip currents are highly unstable and the linear stability model can predict the scales of the observed unsteady motions.

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11

Schlatter, Thomas. "Weather Queries: Rip Currents." Weatherwise 43, no. 3 (June 1990): 165. http://dx.doi.org/10.1080/00431672.1990.9927134.

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Barlas, Baris, and Serdar Beji. "RIP CURRENT FATALITIES ON THE BLACK SEA BEACHES OF ISTANBUL AND EFFECTS OF WINDS." Coastal Engineering Proceedings, no. 35 (June 23, 2017): 15. http://dx.doi.org/10.9753/icce.v35.waves.15.

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This study investigates fatalities due to rip currents on the Black Sea coast of Istanbul. Results include the incidence rate of fatalities from rip currents, their causes, temporal and spatial distributions. The data shows that, nearly 70% of all drowning fatalities are associated with rip currents, and that on the average 33 people reportedly die from rip currents each year in Istanbul Black Sea coast. Thus, considering the wind speeds versus rip current fatalities, about one third of the fatalities occur when the wind speed is between 1.5-2.0 m/s. For the wind speeds 1.0-1.5 m/s the rip current magnitude is not too intense so people consider themselves capable enough to swim but for poor swimmers this is the most dangerous case. Nearly 60% of the fatalities in this wind speed interval is found to be children.

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13

Deguchi, Ichiro, Mamoru Arita, and Takumi Yoshii. "FLUCTUATION OF RIP CURRENT MEASURED IN SHALLOW WATER REGION WITH SMALL TIDAL RANGE." Coastal Engineering Proceedings 1, no. 32 (January 25, 2011): 44. http://dx.doi.org/10.9753/icce.v32.currents.44.

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Disappearance and formation processes of rip channel are discussed based on the field measurements of wave height, current velocity, bottom topography and flow pattern of near-shore current. Sudden increase in wave height together with the change in the wave direction took place during a half day caused these phenomena and rip current rose and fell according to the transition of the bottom topography. Furthermore, flow pattern of rip current was not steady but transformed itself with low frequency fluctuations of the period of few minutes. It is found that such low frequency fluctuations are caused by the intrinsic fluctuations of the incident waves (grouping waves) through the numerical simulations.

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Cong, Nguyen Chi, Le Dinh Mau, Nguyen Van Tuan, Nguyen Thi Thuy Dung, Phan Thanh Bac, Pham Sy Hoan, and Tran Van Binh. "Rip current simulation on some beaches in coastal Quang Nam province." Tạp chí Khoa học và Công nghệ biển 19, no. 3B (October 21, 2019): 113–24. http://dx.doi.org/10.15625/1859-3097/19/3b/14519.

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This paper presents modelling results of rip currents on the main beaches along coastal Quang Nam province including Ha My, Binh Minh, Tam Thanh and Rang beaches during two typical wind seasons: Northeast monsoon (Northeast wind direction, wind levels: 4, 5, 6) and Southwest monsoon (Southeast wind direction, wind levels: 4, 5) using Mike 21 model. Calculation results show that during the Northeast monsoon, the rip current formed in all beaches. In the scenario of level 4 of wind speed, average rip speed was about 40–50 cm/s. In particular, at Tam Thanh beach area, the rip was a typical one with the components such as feeder current, rip neck and rip head. With the level 5 of wind field, the formation of the rip was clearer, the speed of the rip was stronger, average value was about 50–60 cm/s. Meanwhile, with the level 6 of wind field, the typical rip structure was broken, creating local eddies or longshore currents at some positions, but strengthened at other positions. During the Southwest monsoon, the rip current did not form at the beaches and the longshore currents were dominant.

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Hamsan, Muhammad Amirul Syafiq, and Muhammad Zahir Ramli. "Rip current occurrence probability at selected recreational beaches along Pahang coastline." Ecofeminism and Climate Change 1, no. 1 (May 18, 2020): 37–50. http://dx.doi.org/10.1108/efcc-03-2020-0005.

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Purpose Pahang beaches draw more than thousand visitors throughout the year. From the year 2006 to 2018, more than 30 drowning and near-drowning cases were recorded mainly from rip currents. Rip currents are defined as unexpected currents that carried beachgoers away to seaward direction more than approximately 50 m from shore. The prediction of rip current development is very important for the protection of human life. This study aims to conduct preliminary survey and field works to identify rip current hazards. Design/methodology/approach The output would be an early warning preventative mitigation to public in Pahang. Beach state model, dimensionless fall velocity, littoral environment observation and relative tidal range were recorded for five recreational beaches during two different months (March and April 2018). The morphodynamic parameters such sediment fall velocity, sediment grain size and beach slope are then analysed using software PROFILER. Classification of risks was done based on beach morphodynamic model. The morphodynamics are classified as low tide bar rip, barred and low tide terrace associated with rip current, bar dissipative, reflective, non-bar dissipative, low tide terrace and ultra-dissipative. Findings Result shows three out of five recreational beaches may develop high-risk rip currents. During the first month of the survey, Batu Hitam (BH) was recorded the only one recreational beach that may develop high-risk rip current followed by Teluk Cempedak (TC) and Kempadang (KEM) as middle-risk rip current beaches, while Balok (BA) and Sepat (SEP) as low-risk rip current beaches. Different during second month of the survey, BA, BH and SEP were recorded as high-risk rip current beaches while TC and KEM as low-risk rip current beaches. Originality/value The results are consistent with beach incidents (drowning and near-drowning) reported.

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Rampal, Neelesh, Tom Shand, Adam Wooler, and Christo Rautenbach. "Interpretable Deep Learning Applied to Rip Current Detection and Localization." Remote Sensing 14, no. 23 (November 29, 2022): 6048. http://dx.doi.org/10.3390/rs14236048.

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A rip current is a strong, localized current of water which moves along and away from the shore. Recent studies have suggested that drownings due to rip currents are still a major threat to beach safety. Identification of rip currents is important for lifeguards when making decisions on where to designate patrolled areas. The public also require information while deciding where to swim when lifeguards are not on patrol. In the present study we present an artificial intelligence (AI) algorithm that both identifies whether a rip current exists in images/video, and also localizes where that rip current occurs. While there have been some significant advances in AI for rip current detection and localization, there is a lack of research ensuring that an AI algorithm can generalize well to a diverse range of coastal environments and marine conditions. The present study made use of an interpretable AI method, gradient-weighted class-activation maps (Grad-CAM), which is a novel approach for amorphous rip current detection. The training data/images were diverse and encompass rip currents in a wide variety of environmental settings, ensuring model generalization. An open-access aerial catalogue of rip currents were used for model training. Here, the aerial imagery was also augmented by applying a wide variety of randomized image transformations (e.g., perspective, rotational transforms, and additive noise), which dramatically improves model performance through generalization. To account for diverse environmental settings, a synthetically generated training set, containing fog, shadows, and rain, was also added to the rip current images, thus increased the training dataset approximately 10-fold. Interpretable AI has dramatically improved the accuracy of unbounded rip current detection, which can correctly classify and localize rip currents about 89% of the time when validated on independent videos from surf-cameras at oblique angles. The novelty also lies in the ability to capture some shape characteristics of the amorphous rip current structure without the need of a predefined bounding box, therefore enabling the use of remote technology like drones. A comparison with well-established coastal image processing techniques is also presented via a short discussion and easy reference table. The strengths and weaknesses of both methods are highlighted and discussed.

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Brander, R., D. Dominey-Howes, C. Champion, O. Del Vecchio, and B. Brighton. "Brief Communication: A new perspective on the Australian rip current hazard." Natural Hazards and Earth System Sciences 13, no. 6 (June 28, 2013): 1687–90. http://dx.doi.org/10.5194/nhess-13-1687-2013.

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Abstract. Rip currents are strong, narrow offshore flows of water which occur on many of the world's beaches and represent a serious hazard to bathers. In Australia, rip currents account for an average of 21 confirmed human fatalities per year. Based on an analysis of the longest existing data records, rip currents account for more human fatalities in Australia on average each year than bushfires, floods, and cyclones combined. This finding raises important questions regarding the levels of attention placed on the low intensity, but high frequency rip current hazard in relation to high profile and episodic natural hazards.

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Choi, Junwoo. "A Numerical Study of Rip Current Generation Modulated with Tidal Elevations at the Daecheon Beach." Journal of Korean Society of Coastal and Ocean Engineers 34, no. 6 (December 27, 2022): 247–57. http://dx.doi.org/10.9765/kscoe.2022.34.6.247.

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In order to investigate the generations of rip currents modulated with the tidal elevations at a mega-tidal beach at the West Sea coast, numerical simulations of rip currents over the topography of the Daecheon beach were performed by using a Boussinesq-type wave and current model, FUNWAVE. The mega-tidal coast includes rocky outcrops (i.e., reefs) lying over or under the water surface according to the tidal elevations in the offshore and nearshore bathymetry. The offshore topographically-controlled rip currents were well reproduced due to the alongshore non-uniformities transformed by the tide-modulated topography. This study addressed the generation types of rip currents to occur at the mega-tidal coast with the tide-modulated outcrops and reefs.

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Mucerino, Luigi, Luca Carpi, Chiara F. Schiaffino, Enzo Pranzini, Eleonora Sessa, and Marco Ferrari. "Rip current hazard assessment on a sandy beach in Liguria, NW Mediterranean." Natural Hazards 105, no. 1 (September 14, 2020): 137–56. http://dx.doi.org/10.1007/s11069-020-04299-9.

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AbstractRip currents are one of the most significant environmental hazards for beachgoers and are of interest to coastal scientists. Several studies have been conducted to understand rip current dynamics, and several approaches for rip hazard assessment have been proposed. In general, the purpose is to provide knowledge and tools to support authorities and lifeguards in rip current risk prevention. This study proposes the application of an expeditious methodology to evaluate rip current hazard and risk, based on probability theory. The tested area was located along the Alassio beach, a renowned tourist destination located on the western Ligurian coast (NW Italy). A coastal video-monitoring system was used for rip currents individuation, whereas wave data were collected thanks to an oceanographic buoy managed by Regione Liguria. In detail, a yearly analysis was performed to identify the correspondence between rip currents and wave parameters data. The results showed that rip currents occur, in the study area, under moderate wave conditions ($$0.5 \le H_s \le 1.34$$ 0.5 ≤ H s ≤ 1.34 m; $$4.7\le T_m \le 7.0$$ 4.7 ≤ T m ≤ 7.0 s; $$150^{\circ }\,\hbox {N} \le \theta _m \le 227^{\circ }$$ 150 ∘ N ≤ θ m ≤ 227 ∘ N). Based on this analysis, an easy application of the probability theory was applied to evaluate the level of hazard. Moreover, considering the official tourist data, we also perform an expeditious rip currents risk evaluation. The results showed that the hazard level is considered high at annual time scale and moderate during the tourist season; the risk is related to seasonal presences. The study can propose a tool to support authorities and lifeguards in water safety planning and management.

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Withers, Archie, and Sergio Maldonado. "On the swimming strategies to escape a rip current: a mathematical approach." Natural Hazards 108, no. 2 (April 22, 2021): 1449–67. http://dx.doi.org/10.1007/s11069-021-04740-7.

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AbstractRip currents represent significant hazards to swimmers all around the world. The danger arises when a misinformed swimmer uses an inadequate strategy to escape the rip, such as fighting the current directly. This can lead to fatigue, panic, and in some cases drowning. There exists a range of strategies put forward by experts (both lifeguards and scientists) to escape rip currents. However, these recommendations are based on a limited number of scientific studies and there is still much discrepancy surrounding the best strategy to escape a rip. Thus, here we present a simple, physics-based theoretical model aimed at assessing different escape strategies in terms of their associated ‘energetic cost’ (in work and power) for any given rip current and swimmer’s proficiency level. Many combinations of swimmers and rips are considered, including both idealised and a realistic rip current. Our quantitative results back the common knowledge that swimming against the rip (which is strongly discouraged by lifeguards) is almost universally the worst possible strategy, especially when compared against strategies favoured by experts, such as floating with the current before attempting to swim back to the shore. For a realistic rip, our results suggest that swimming directly against the rip can require several times more power from the swimmer than other strategies advised by lifeguards, thus lending further scientific support to experts’ recommendations. This study may help promote education around the dangers posed by rip currents and how best to address them.

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Kenyon, Kern E. "Rip Currents Have Least Friction." Natural Science 12, no. 05 (2020): 292–94. http://dx.doi.org/10.4236/ns.2020.125025.

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Vagle, Svein, David M. Farmer, and Grant B. Deane. "Bubble transport in rip currents." Journal of Geophysical Research: Oceans 106, no. C6 (June 15, 2001): 11677–89. http://dx.doi.org/10.1029/2000jc000276.

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Takewaka, Satoshi, and Taishi Yamakawa. "RIP CURRENT OBSERVATION WITH X-BAND RADAR." Coastal Engineering Proceedings 1, no. 32 (January 29, 2011): 43. http://dx.doi.org/10.9753/icce.v32.currents.43.

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X-band radar measurements were conducted at the research pier HORS, of the Port and Airport Research Institute, located in Hasaki, Japan. Ensembles of original radar images over 17 minutes were processed to time-averaged radar images every hour, which were analyzed to estimate the intertidal morphology and occurrence of rip currents. Several streaks extending in the cross shore direction appear in the averaged images which resemble to a neck and head of a rip current captured often in aerial photos or video imageries. The natures of these characteristic patterns in the time-averaged image are investigated through comparisons between optical images, floater release experiment and statistic analyses on sea conditions.

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Brighton, B., S. Sherker, R. Brander, M. Thompson, and A. Bradstreet. "Rip current related drowning deaths and rescues in Australia 2004–2011." Natural Hazards and Earth System Sciences 13, no. 4 (April 22, 2013): 1069–75. http://dx.doi.org/10.5194/nhess-13-1069-2013.

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Abstract. Rip currents are a common hazard to beachgoers found on many beaches around the world, but it has proven difficult to accurately quantify the actual number of rip current related drowning deaths in many regions and countries. Consequently, reported estimates of rip current drowning can fluctuate considerably and are often based on anecdotal evidence. This study aims to quantify the incidence of rip current related drowning deaths and rescues in Australia from 2004 to 2011. A retrospective search was undertaken for fatal and non-fatal rip-related drowning incidents from Australia's National Coronial Information System (NCIS), Surf Life Saving Australia's (SLSA, 2005–2011) SurfGuard Incident Report Database (IRD), and Media Monitors for the period 1 July 2004 to 30 June 2011. In this time, rip currents were recorded as a factor in 142 fatalities of a total of 613 coastal drowning deaths (23.2%), an average of 21 per year. Rip currents were related to 44% of all beach-related drowning deaths and were involved in 57.4% of reported major rescues in Australian locations where rips occur. A comparison with international operational statistics over the same time period describes rip-related rescues as 53.7% of the total rescues in the US, 57.9% in the UK and 49.4% in New Zealand. The range 49–58% is much lower than 80–89% traditionally cited. The results reported are likely to underestimate the size of the rip current hazard, because we are limited by the completeness of data on rip-related events; however this is the most comprehensive estimate to date. Beach safety practitioners need improved data collection and standardized definitions across organisations. The collection of drowning data using consistent categories and the routine collection of rip current information will allow for more accurate global comparisons.

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Widartono, Barandi Sapta, Muchsin Nur Wachid, Deha Agus Umarhadi, Anggini Nur Azizah, and Restu Dwi Cahyo. "Kite Aerial Photography (KAP) for rip current identification in Parangtritis Beach." E3S Web of Conferences 76 (2019): 03005. http://dx.doi.org/10.1051/e3sconf/20197603005.

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Rip current is being the major cause of the deadly accidents in Parangtritis Beach. This occasion can be prevented by mapping and monitoring the spatial pattern of rip currents at the location which rip currents are located. Rip current location can be identified by remote sensing data or aerial observations, such as Kite Aerial Photography (KAP). This platform is low cost and can be performed in coastal area due to the massive winds there. KAP has been widely used as the platform for mapping, and some of them are implemented in coastal area. This study aims to find out the ability of Kite aerial photography to identify the rip current location in Parangtritis Beach. From several flight tests, the photo mosaic of Parangtritis Beach has been generated after the KAP has flown at the minimum 3 m/s of the wind speed. KAP can be the great potentials in coastal monitoring, especially for rip current monitoring because it is low-cost, low-energy and provides actual information.

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Ghorbani, Ali. "The modelling of rip channel in creation of rip currents." Indian Journal of Science and Technology 5, no. 4 (April 20, 2012): 1–5. http://dx.doi.org/10.17485/ijst/2012/v5i4.16.

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Moulton, Melissa, Gregory Dusek, Steve Elgar, and Britt Raubenheimer. "Comparison of Rip Current Hazard Likelihood Forecasts with Observed Rip Current Speeds." Weather and Forecasting 32, no. 4 (August 1, 2017): 1659–66. http://dx.doi.org/10.1175/waf-d-17-0076.1.

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Abstract Although rip currents are a major hazard for beachgoers, the relationship between the danger to swimmers and the physical properties of rip current circulation is not well understood. Here, the relationship between statistical model estimates of hazardous rip current likelihood and in situ velocity observations is assessed. The statistical model is part of a forecasting system that is being made operational by the National Weather Service to predict rip current hazard likelihood as a function of wave conditions and water level. The temporal variability of rip current speeds (offshore-directed currents) observed on an energetic sandy beach is correlated with the hindcasted hazard likelihood for a wide range of conditions. High likelihoods and rip current speeds occurred for low water levels, nearly shore-normal wave angles, and moderate or larger wave heights. The relationship between modeled hazard likelihood and the frequency with which rip current speeds exceeded a threshold was assessed for a range of threshold speeds. The frequency of occurrence of high (threshold exceeding) rip current speeds is consistent with the modeled probability of hazard, with a maximum Brier skill score of 0.65 for a threshold speed of 0.23 m s−1, and skill scores greater than 0.60 for threshold speeds between 0.15 and 0.30 m s−1. The results suggest that rip current speed may be an effective proxy for hazard level and that speeds greater than ~0.2 m s−1 may be hazardous to swimmers.

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Suarez, Leandro, Rodrigo Cienfuegos, Eric Barthélemy, Hervé Michallet, and Cristian Escauriaza. "LAGRANGIAN DRIFTER MODELLING OF AN EXPERIMENTAL RIP CURRENT." Coastal Engineering Proceedings 1, no. 33 (October 25, 2012): 35. http://dx.doi.org/10.9753/icce.v33.currents.35.

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A non-uniform alongshore wave forcing on an experimental uneven mobile bathymetry create mean circulation on a rip channel. A 2D numerical hydrodynamic model that integrates the non-linear shallow-water equations in a shock-capturing finite-volume framework is used to validate the nearshore circulation, and drifters displacement.

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29

Arun Kumar, S. V. V., and K. V. S. R. Prasad. "Rip current-related fatalities in India: a new predictive risk scale for forecasting rip currents." Natural Hazards 70, no. 1 (August 1, 2013): 313–35. http://dx.doi.org/10.1007/s11069-013-0812-x.

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30

Fletemeyer, John, and Stephen Leatherman. "Rip Currents and Beach Safety Education." Journal of Coastal Research 261 (January 2010): 1–3. http://dx.doi.org/10.2112/09a-0005.1.

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31

Yu, Jie, and Siyu Chen. "Hydrodynamic Instability Mechanism for Rip Currents." Studies in Applied Mathematics 135, no. 2 (February 17, 2015): 196–223. http://dx.doi.org/10.1111/sapm.12074.

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32

GRUSZCZYNSKI, MICHAL, STANISLAW RUDOWSKI, JULIA SEMIL, JAN SLOMINSKI, and JERZY ZROBEK. "Rip currents as a geological tool." Sedimentology 40, no. 2 (April 1993): 217–36. http://dx.doi.org/10.1111/j.1365-3091.1993.tb01762.x.

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33

Kennedy, Andrew B., Yang Zhang, and Kevin A. Haas. "Rip Currents with Varying Gap Widths." Journal of Waterway, Port, Coastal, and Ocean Engineering 134, no. 1 (January 2008): 61–65. http://dx.doi.org/10.1061/(asce)0733-950x(2008)134:1(61).

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34

Smith, Jerome A., and John L. Largier. "Observations of nearshore circulation: Rip currents." Journal of Geophysical Research 100, no. C6 (1995): 10967. http://dx.doi.org/10.1029/95jc00751.

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35

Johnson, D., and C. Pattiaratchi. "Boussinesq modelling of transient rip currents." Coastal Engineering 53, no. 5-6 (April 2006): 419–39. http://dx.doi.org/10.1016/j.coastaleng.2005.11.005.

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36

Kim, Hyun Dong, and Kyu-Han Kim. "Analysis of Rip Current Characteristics Using Dye Tracking Method." Atmosphere 12, no. 6 (June 3, 2021): 719. http://dx.doi.org/10.3390/atmos12060719.

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Rip currents are strong water channels flowing away from the shoreline. They can occur on any shore with breaking waves. Rip currents play a significant role in changing the topography of shallow water regions by transporting large amounts of bed material offshore. Moreover, they pose a significant danger for people living in nearshore zones and surfers and cause hundreds of deaths annually worldwide. Therefore, rip current generation characteristics have been investigated to prevent casualties. In this study, a GPS drifter survey was chosen as the investigation method; however, a few drawbacks were discovered, such as low accuracy due to the GPS drifter becoming trapped in the surf zone. Therefore, drones and dyes were used to overcome the drawbacks of drifter methods. The results of dye tracking and the 3D wave-induced current numerical simulation were compared; the velocity and formation of the rip current were found to be relatively similar. With the technological advancements and invention of new survey equipment, the survey techniques also evolve, and this paper shows that the disadvantages of the GPS-based Lagrangian method can be overcome using a dye-mounted drone, which observes the rip current easily and accurately.

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37

Benassai, Guido, Pietro Aucelli, Giorgio Budillon, Massimo De Stefano, Diana Di Luccio, Gianluigi Di Paola, Raffaele Montella, Luigi Mucerino, Mario Sica, and Micla Pennetta. "Rip current evidence by hydrodynamic simulations, bathymetric surveys and UAV observation." Natural Hazards and Earth System Sciences 17, no. 9 (September 12, 2017): 1493–503. http://dx.doi.org/10.5194/nhess-17-1493-2017.

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Abstract. The prediction of the formation, spacing and location of rip currents is a scientific challenge that can be achieved by means of different complementary methods. In this paper the analysis of numerical and experimental data, including RPAS (remotely piloted aircraft systems) observations, allowed us to detect the presence of rip currents and rip channels at the mouth of Sele River, in the Gulf of Salerno, southern Italy. The dataset used to analyze these phenomena consisted of two different bathymetric surveys, a detailed sediment analysis and a set of high-resolution wave numerical simulations, completed with Google EarthTM images and RPAS observations. The grain size trend analysis and the numerical simulations allowed us to identify the rip current occurrence, forced by topographically constrained channels incised on the seabed, which were compared with observations.

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38

Thornton, E. B., J. MacMahan, and A. H. Sallenger. "Rip currents, mega-cusps, and eroding dunes." Marine Geology 240, no. 1-4 (June 2007): 151–67. http://dx.doi.org/10.1016/j.margeo.2007.02.018.

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39

Long, J. W., and H. T. Özkan‐Haller. "Forcing and variability of nonstationary rip currents." Journal of Geophysical Research: Oceans 121, no. 1 (January 2016): 520–39. http://dx.doi.org/10.1002/2015jc010990.

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40

Huntley, David A., and Andy D. Short. "On the spacing between observed rip currents." Coastal Engineering 17, no. 3-4 (August 1992): 211–25. http://dx.doi.org/10.1016/0378-3839(92)90052-v.

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41

Weber, Jan Erik H. "Equatorial Stokes drift and Rossby rip currents." Journal of Geophysical Research: Oceans 122, no. 6 (June 2017): 4819–28. http://dx.doi.org/10.1002/2016jc012653.

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42

Brewster, B. Chris, Richard E. Gould, and Robert W. Brander. "Estimations of rip current rescues and drowning in the United States." Natural Hazards and Earth System Sciences 19, no. 2 (February 22, 2019): 389–97. http://dx.doi.org/10.5194/nhess-19-389-2019.

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Abstract. Rip currents are the greatest hazard to swimmers on surf beaches, but due to a lack of consistent incident reporting in many countries, it is often difficult to quantify the number of rip-current-related rescues and drowning deaths occurring along surf beaches. This study examines this problem using rescue data reported to the United States Lifesaving Association (USLA) by surf beach rescuers from 1997 through 2016. These data were checked, corrected, and culled so that only data from surf beach rescue agencies that reported the primary cause of rescue were included. Results show that rip currents are the primary cause of 81.9 % of rescues on surf beaches, with regional variation from 75.3 % (East Coast) to 84.7 % (West Coast). These values are significantly higher than those previously reported in the scientific literature (e.g., 36.5 %, 53.7 %). Using this value as a proxy when examining overall surf beach drowning fatalities, it is suggested that more than 100 fatal drownings per year occur due to rip currents in the United States. However, it is clear that the United States data would benefit by an increase in the number of lifeguard agencies which report surf-related rescues by primary cause.

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43

Mau, Le Dinh, Nguyen Van Tuan, Nguyen Chi Cong, Tran Van Binh, Pham Ba Trung, Pham Sy Hoan, Ngo Quang Bao Hoang, and Phan Thi Ha Tuyen. "Occurrence features of Rip current at Ha My (Dien Ban district) and Tam Thanh (Tam Ky city) beaches, Quang Nam province." Tạp chí Khoa học và Công nghệ biển 19, no. 4A (November 8, 2019): 43–53. http://dx.doi.org/10.15625/1859-3097/19/4a/14587.

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Rip current is a relatively strong, narrow current flowing outward from the beach through the surf zone and presenting a hazard to swimmers. This paper presents some occurrence features of Rip current at main swimming beaches in Quang Nam province, Central Vietnam. Study results show that most of swimming beaches along Quang Nam province coast are directly opposed to open sea and strongly affected by swell. Therefore, Rip current system can occur at any time in the year with large dimension and intensity. During Northeast monsoon (November to March) beach morphology is considerably changed by strong wave action, thus the strongest rip current is formed. However, in this period careful swimmers can easily identify where that rip current occurs along the beach. During the transition period from Northeast monsoon to Southwest monsoon (April to May) wave energy is reduced, thus Rip current intensity is also decreased. During Southwest monsoon (June to August) wave energy is not strong and beach is accreted, therefore some Rip currents remain at reasonable morphology places along the beach. During the transition period from Southwest monsoon to Northeast monsoon (September to October) Rip current can occur at deep places along the beach with characteristics of narrow dimension, thus causing more danger to swimmer. Especially, dangerous rip current is caused by swell which comes from active region of tropical cyclone in open sea. In this period wave field in the nearshore region is not rough, thus most of swimmers are not cautious when swimming at dangerous rip current places.

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44

De Zeeuw, Roeland, Matthieu A. De Schipper, Dano Roelvink, Sierd De Vries, and Marcel J. F. Stive. "IMPACT OF NOURISHMENTS ON NEARSHORE CURRENTS AND SWIMMER SAFETY ON THE DUTCH COAST." Coastal Engineering Proceedings 1, no. 33 (December 15, 2012): 57. http://dx.doi.org/10.9753/icce.v33.currents.57.

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Assessing swimmer safety along the Dutch coast entails more than only assessing the risk of rip currents. Seven criteria have been formulated to make a comprehensive assessment of swimmer safety along the Dutch coast. These are based on interviews with lifeguards, rescue report statistics and detailed lagrangian measurements of the current patterns and bathymetry in the shallow nearshore, at three different field sites along the South-Holland coast.

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45

Winter, G., A. R. van Dongeren, M. A. de Schipper, and J. S. M. van Thiel de Vries. "Rip currents under obliquely incident wind waves and tidal longshore currents." Coastal Engineering 89 (July 2014): 106–19. http://dx.doi.org/10.1016/j.coastaleng.2014.04.001.

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46

Reyes, Clint Chester, Eric Cruz, and Jose Carlo Eric Santos. "CASE STUDY OF NEARSHORE CURRENTS HAZARD ANALYSIS FOR RECREATIONAL BEACH DEVELOPMENT." Coastal Engineering Proceedings, no. 36v (December 31, 2020): 20. http://dx.doi.org/10.9753/icce.v36v.papers.20.

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Nearshore current generation at two coastlines contemplated for beach resort development is studied with the use of a numerical model for coexisting waves and currents. A nested-mesh technique was applied to consolidate the 2 domains of coarse and fine bathymetric data and to translate deep water wave conditions at the nearshore mesh boundary. The hydrodynamic model is validated using tide data at the nearest tide stations, while offshore wave conditions, determined from a wave hindcasting method, are inputted as quasi-stationary forcing. Simulations results of wave-current co-existing fields indicate local areas of rip currents within the project coastlines. In order to evaluate the safe swimming zones, an analysis of threshold currents under idealized conditions of human characteristics was carried out, that indicated a threshold of 0.16 mps for pure currents. With a safety margin to account for co-existing waves, rip current zones not exceeding 0.1 mps are considered safe and are used to designate the safe swimming areas for the 2 locations.

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47

Yoon, Sung B., and Philip L. F. Liu. "WAVE AND CURRENT INTERACTIONS IN SHALLOW WATER." Coastal Engineering Proceedings 1, no. 20 (January 29, 1986): 125. http://dx.doi.org/10.9753/icce.v20.125.

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Interactions between waves and currents are common and important phenomena in the coastal zone. Coastal currents, such as longshore currents, rip currents, and river flows, can significantly change wave heights and directions of wave propagation. Consequently, the design for shoreline protection measures must be adjusted accordingly. Various theories for wave-current interactions exist and have been reviewed by Peregrine and Jonsson (1983). Most of these theories are developed for large-scale currents where the length-scale for the current variation is much greater than the typical wavelength. These theories cannot be applied to the coastal currents which are small-scale currents. In this paper, the interactions between currents and nonlinear shallow water waves are investigated. Boussinesq equations are used to derive evolution equations for spectral wave components. The current intensity is assumed to be larger than the leading wave orbital velocity and smaller than the group velocity. The length-scale of the current is much shorter than those assumed in the existing large-scale theories. To facilitate numerical computations, the parabolic approximation is applied and a simplified model is developed. A numerical example is given for the refraction and diffraction of cnoidal waves over a rip current on a sloping topography. Both normal and oblique incident cases are examined.

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48

Houser, Chris, Sarah Trimble, Robert Brander, B. Chris Brewster, Greg Dusek, Deborah Jones, and John Kuhn. "Public perceptions of a rip current hazard education program: “Break the Grip of the Rip!”." Natural Hazards and Earth System Sciences 17, no. 7 (July 4, 2017): 1003–24. http://dx.doi.org/10.5194/nhess-17-1003-2017.

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Abstract. Rip currents pose a major global beach hazard; estimates of annual rip-current-related deaths in the United States alone range from 35 to 100 per year. Despite increased social research into beach-goer experience, little is known about levels of rip current knowledge within the general population. This study describes the results of an online survey to determine the extent of rip current knowledge across the United States, with the aim of improving and enhancing existing beach safety education material. Results suggest that the US-based Break the Grip of the Rip!® campaign has been successful in educating the public about rip current safety directly or indirectly, with the majority of respondents able to provide an accurate description of how to escape a rip current. However, the success of the campaign is limited by discrepancies between personal observations at the beach and rip forecasts that are broadcasted for a large area and time. It was the infrequent beach user that identified the largest discrepancies between the forecast and their observations. Since infrequent beach users also do not seek out lifeguards or take the same precautions as frequent beach users, it is argued that they are also at greatest risk of being caught in a dangerous situation. Results of this study suggest a need for the national campaign to provide greater focus on locally specific and verified rip forecasts and signage in coordination with lifeguards, but not at the expense of the successful national awareness program.

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Ostrowski, Rafał, Jan Schönhofer, Magdalena Stella, Alexey Grave, Aleksander Babakov, and Boris Chubarenko. "South Baltic rip currents detected by a field survey." Baltica 33, no. 1 (August 1, 2020): 11–20. http://dx.doi.org/10.5200/baltica.2020.1.2.

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The paper presents results of experimental investigations of currents in the nearshore region of the south Baltic Sea. The analysis is based on the field data collected near Lubiatowo (Poland) using the measuring equipment which was simultaneously operated both by the Polish and Russian research teams. The venture was aimed at detection of rip currents that are rare and insufficiently explored phenomena in the south Baltic coastal zone. The data include wind velocity and direction, deep-water wave buoy records and currents surveyed by means of drifters. The measurements were carried out in the area whose hydrodynamics, lithodynamics and morphodynamics are typical of the south Baltic sandy coast. It appears that the nearshore water flows are mostly represented by longshore wave-driven currents with mean velocities of 0.22–0.53 m/s, and the maximum velocity of 1.32 m/s. Water circulation patterns resembling rip currents with velocities of up to 0.34 m/s were identified only on one day, when specific wave conditions occurred at the study site. Contrary to strong longshore currents generated by storm waves, rip currents occur under mild or moderate wave conditions, when many beach users are willing to swim in nearshore waters. The present findings can therefore be useful for the improvement of swimmers’ safety in the south Baltic Sea regions.

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50

Hosoyamada, Tokuzo, Harumi Murakawa, and Naoyuki Inukai. "Interactions of rip currents and coastal bathymetry change." Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 67, no. 2 (2011): I_556—I_560. http://dx.doi.org/10.2208/kaigan.67.i_556.

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Journal articles on the topic 'Rip currents'

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