ОкеанологияОкеанология0030-1574The Russian Academy of Sciences1443410.31857/S0030-1574593497-505Research ArticleRhythmic patterns of shoreline contour in the gulf of Terpenya of Sakhalin IslandLeont’yevI. O.igor.leontyev@gmail.comAfanas'yevV. V.vvasand@mail.ruUbaA. V.vvasand@mail.ruShirshov Institute of Oceanology, Russian Academy of SciencesInstitute of Marine Geology and Geophysics, Far Eastern Branch, Russian Academy of Sciences260620195934975052606201926062019Copyright © 2019, Russian academy of sciences2019<p>The results are discussed of the long-term observations of the system of mega-cusps (large-scale shoreline cusps) revealed on the coast of the Gulf of Terpenya of Sakhalin Island. Typical spatial step of the rhythmic forms is about 800 m and the amplitude of shoreline undulations is of tens of meters. Despite of significant changes in temporal scales of the seasons, years and decades the main morphological features of mega-cusps are kept over the period of more than 60 years. The model is suggested explaining creation of rhythmic shoreline patterns by self-organization of bottom relief under the wave impact. Development of mega-cusps is shown to be connected with generation of nearshore circulation cells. Due to flows within the cells a small initial perturbation of shoreline contour can increase in time. A positive feedback between the coastal morphology and the hydrodynamics arises when a certain relation is established between the length of perturbation, the width of surf zone and the velocities of nearshore currents. It is concluded that the system of mega-cusps in the Gulf of Terpenya is mainly supported by the moderate waves of significant wave height about 1.6 m.</p>shoreline contourmegacuspscirculation cellsself-organization of bed reliefконтур берегамегафестоныциркуляционные ячейкисамоорганизация рельефа дна[Афанасьев В.В. Геоморфологические аспекты проблемы защиты берегов острова Сахалин // Геоморфология. 2015. № 2. С. 28–37.][Афанасьев В.В., Мыглан М.Ю., Типер А.И. Прогноз размыва аккумулятивных берегов // Юбилейный вып. ДВНИГМИ — 50 лет. Владивосток: Дальнаука, 2000. С. 49–50.][Афанасьев В.В., Игнатов Е.И., Сафьянов Г.А., Чистов С.В. Защита берегов в п. Взморье, остров Сахалин, методом компенсации дефицита наносов // Труды междунар. конф. «Создание и использование искусственных земельных участков на берегах и акватории водоемов», 20–25 июля 2009. Иркутск: ИЗК СО РАН, 2009. С. 181–187.][Афанасьев В.В., Уба А.В. Анализ размыва берегов северо-восточного Сахалина // Геоморфология. 2019. (Принято к печати).][Гидрометеорология и гидрохимия морей. Т. 9. Охотское море. Вып. 1. Гидрометеорологические условия. СПб.: Гидрометеоиздат, 1998. 370 с.][Горбунов А.О., Зарочинцев В.С., Королев П.Ю. Роль аллювия в компенсации дефицита пляжевых отложений залива Терпения (о. Сахалин) // Изв. Самарского науч. центра РАН. 2010. Т. 12. № 1(4). С. 1002–1005.][Зенкович В.П. Основы учения о развитии морских берегов. М.: Изд-во АН СССР, 1962. 710 с.][Леонтьев И.О. Морфодинамические процессы в береговой зоне моря. Saarbrücken: LAP LAMBERT Academic Publishing, 2014. 251 c.][Плеханов Ф. А. Пространственно-временная изменчивость характеристик волнения у юго-восточного побережья о. Сахалин по данным инструментальных измерений // Ученые записки Сахалинского государственного университета. 2015. №. 1. С. 35–38.][Ashton A.D., Murray A.B. High-angle wave instability and emergent shoreline shapes: 2. Wave climate analysis and comparisons to nature // J. of Geophys. Res. 2006. V. 111. F04012. Doi:10.1029/2005JF000423.][Ashton A.D., Murray A.B., Arnault O. Formation of coastline features by large-scale instabilities induced by high-angle waves // Nature. 2001. V. 414. P. 296–300.][Bowen A.J., Huntley D.A. Waves, long waves and nearshore topography // Marine Geol. 1984. V. 60. P. 1–13.][Bowen A.J., Inman D.L. Rip currents. Part 2. Laboratory and field observations // J. of Geophys. Res. 1969. V. 74. № 23. P. 5479–5490.][Brander R.W. Field observations on the morphodynamic evolution of a low-energy rip current system // Marine Geol. 1999. V. 157. P. 199–217.][Bruun P. The Bruun rule of erosion by sea-level rise: a discussion on large-scale twoand three-dimensional usages // J. of Coastal Res. 1988. V. 4. № 4. P. 627–648.][Falqués A. Wave driven alongshore sediment transport and stability of the Dutch coastline // Coastal Eng. 2006. V. 53. P. 243–254.][Falqués A., Coco G., Huntley D.A. A mechanism for the generation of wave-driven rhythmic patterns in the surf zone // J. of Geophys. Res. 2000. V. 105. № C10. P. 24071–24087.][Hino M. Theory on formation of rip current and cuspidal coast // 14th Int. Conf. Coast. Eng. ASCE. 1974. P. 901–919.][Holman R.A., Bowen A.J. Bars, bumps and holes: models for the generation of complex beach topography // J. of Geophys. Res. 1982. V. 87. № C1. P. 457–468.][Thevenot M.M., Kraus N.C. Longshore sand waves at Southampton Beach, New York: observation and numerical simulation of their movement // Marine Geology. 1995. V. 126. P. 249–269.]