scholarly journals Study on Hydrodynamic Characteristics and Environmental Response in Shantou Offshore Area

2021 ◽  
Vol 9 (8) ◽  
pp. 912
Author(s):  
Yuezhao Tang ◽  
Yang Wang ◽  
Enjin Zhao ◽  
Jiaji Yi ◽  
Kecong Feng ◽  
...  
Keyword(s):  
Flow Field ◽  
Water Level ◽  
Tidal Current ◽  
Sea Water ◽  
High Tide ◽  
Spring Tide ◽  
River Estuary ◽  
Tidal Range ◽  
Offshore Area ◽  
Tidal Constituents

As a coastal trading city in China, Shantou has complex terrain and changeable sea conditions in its coastal waters. In order to better protect the coastal engineering and social property along the coast, based on the numerical simulation method, this paper constructed a detailed hydrodynamic model of the Shantou sea area, and the measured tide elevation and tidal current were used to verify the accuracy of the model. Based on the simulation results, the tide elevation and current in the study area were analyzed, including the flood and ebb tides of astronomical spring tide, the flood and ebb tides of astronomical neap tide, the high tide, and the low tide. In order to find the main tidal constituent types in this sea, the influence of different tidal constituents on tide elevation and tidal current in the study area was analyzed. At the same time, the storm surge model of the study area was constructed, and the flow field under Typhoon “Mangkhut” in the study area was simulated by using the real recorded data. Typhoon wind fields with different recurrence periods and intensities were constructed to simulate the change in the flow field, the sea water level, and the disaster situation along the coast. The results showed that under normal sea conditions, the sea water flows from southwest to northeast at flood tide and the flow direction is opposite at ebb tide. The tidal range is large in the northwest and small in the southeast of the study area. The tides in the study area are mainly controlled by M2, S2, K1, and O1 tidal constituents, but N2, K2, P1, and Q1 tidal constituents have significant effects on the high water level. The water level caused by typhoons increases significantly along the coast of Shantou City. In the west area of the Rong River estuary, a typhoon with a lower central pressure than 910 hPa may induce a water increase of more than 2 m.

scholarly journals TIDE AND TIDAL CURRENT IN THE BALI STRAIT, INDONESIA

2015 ◽  
Vol 36 (2) ◽  
pp. 25-36 ◽  
Author(s):  
Dessy Berlianty ◽  
Tetsuo Yanagi
Keyword(s):  
Tidal Current ◽  
Ecological Model ◽  
Current Model ◽  
Spring Tide ◽  
Residual Flow ◽  
Tidal Front ◽  
Shelf Seas ◽  
Shallow Area ◽  
Tidal Constituents ◽  
Tide And Tidal Current

Tide and tidal current model of the Bali Strait in Indonesia is produced by using a Coupled Hydrodynamical-Ecological Model for Regional and Shelf Seas (COHERENS). With its resolutions in the horizontal (500meters) and the vertical (4layers), the model well reproduces the four major tidal constituents, namely M2, S2, K1, and O1 tides, and their currents. Furthermore the model is used to investigate the tide-induced residual flow and tidal front in the Bali Strait. As a results, the tide-induced residual flow in the Bali Strait during the spring tide on May 16th in 2010 can be attributed to the variation of the strength of two eddies. The first one is the clockwise circulation in the shallow area at the wide part of the strait, while the second one is the small clockwise circulation in the south of the narrow strait. On the other hand, as suggestion from Simpson and Hunter (1974), the tidal front is determined by the value of log(H/U3) (where is the water depth in meters and the amplitude oftidal current amplitude in ms-1). The front detected by the image of sea surface temperature distribution from the satellite corresponds with the contour log(H/U3) of 6.5.

scholarly journals Tidal Type Determination on Manokwari Shipping Chanel by Using Admiralty Method

2018 ◽  
pp. 57
Author(s):  
Suhaemi Suhaemi ◽  
Syafrudin Raharjo ◽  
Marhan Marhan
Keyword(s):  
Water Level ◽  
Full Moon ◽  
High Tide ◽  
High Water ◽  
Tidal Range ◽  
Tidal Amplitude ◽  
Gravitational Forces ◽  
Sea Transportation ◽  
Gravitational Pull ◽  
Tidal Waters

Tidal waters are very important for port interests, sea transportation, fisheries industry, coastal engineering and coastal area mitigation. Tidal height formed is a superposition of tidal amplitude due to the gravitational pull of the sun, moon and earth. The Tidal components are K1, O1, P1, S2, M2, K2, M4, MS4. This study aims to determine the components and types of tides in the shipping channel of Manokwari-West Papua using the admiralty method. Formzahl 0.732 number means the type of tidal that is formed is mixed tide prevailing semidiurnal, two high and low tide, two high and one low tide or two times low tide one high tide in a day. Mean Sea Level (MSL) was caused by water conditions, coastlines and bathymetry, the gravitational forces of the moon and sun. The MSL was obtained 98 cm. large tidal range occurs during full moon conditions and low tides occur during perbani (1.62-2.44 m). The amplitude Mean High Water Level level reaches 279 cm and Mean Low Water Level reaches -83 cm.

scholarly journals PENDANGKALAN ALUR PELAYARAN DI PELABUHAN PULAU BAAI BENGKULU

2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Lukman Arifin ◽  
Juniar P. Hutagaol ◽  
Mustafa Hanafi
Keyword(s):  
Water Level ◽  
Current Velocity ◽  
Sea Water ◽  
Neap Tide ◽  
Spring Tide ◽  
Current Measurement ◽  
Geophysical Survey ◽  
Measurement Result ◽  
Level Difference ◽  
Sea Current

Alur pelayaran di Pelabuhan Pulau Baai Bengkulu selalu mengalami pendangkalan. Untuk mengetahui penyebab pendangkalan tersebut maka akan diberikan beberapa informasi hasil kajian geofisika kelautan dari beberapa metoda. Metoda tersebut terdiri dari pengukuran kedalaman laut, pengukuran arus dan pasang surut. Hasil pengukuran kedalaman laut memperlihatkan bahwa kedalaman yang paling dalam di bagian kolam pelabuhan adalah sekitar 12 meter dan yang terdalam di daerah alur juga 12 meter. Pengukuran arus laut memperlihatkan bahwa kecepatan arus pada saat pasang tertinggi lebih tinggi daripada kecepatan arus pada saat surut terendah. Pengendapan lebih besar terjadi pada saat air pasang, apalagi ditambah dengan adanya arus sepanjang pantai yang membawa sedimen ke arah alur. Tipe pasang surut laut di pelabuhan ini adalah tipe campuran ganda, artinya pasang dan surut akan terjadi sekali atau dua kali dalam sehari. Adapun perbedaan tinggi muka air pada saat air pasang dan saat air surut adalah 1,53 meter. Shoaling always occurs in the sailing channel of Pulau Baai Bengkulu Harbour. To know the reason of the shoaling, some information based on the result, of the analysis of several methods of marine geophysical survey are therefore presented. The methods are echo-sounding, sea current and tide measurement. Result of sounding shows that the deepest depth in the lagoon area is around 12 metres and the depth in the channel area is also 12 metres. Result of sea current measurement shows that current velocity during the spring tide is higher than the velocity during the neap tide. Sedimentation is higher in the spring tide, moreover it is increased by the existence of long shore current which transport the sediments into the channel. The type of the sea tide in the harbour is a mixed semi diurnal type which means that the spring and the neap will occur once or twice a day. The height of sea water level difference between spring tide and neap tide season is 1.53 metres.

scholarly journals STRUKTUR KOMUNITAS LARVA IKAN PADA SAAT PASANG SURUT DI MUARA SUNGAI MOROSARI SAYUNG, DEMAK

2018 ◽  
Vol 7 (4) ◽  
pp. 370-378
Author(s):  
Prayogi Pahingguan ◽  
Bambang Sulardiono ◽  
Wiwiet Teguh Taufani
Keyword(s):  
Sea Water ◽  
Fish Larvae ◽  
Diversity Index ◽  
Research Result ◽  
High Tide ◽  
River Estuary ◽  
Survey Method ◽  
Research Station ◽  
Tide Level ◽  
Index Value

Muara Sungai merupakan perairan semi tertutup yang terletak di bagian hilir sungai dan masih berhubungan dengan laut sehingga memungkinkan untuk terjadinya pencampuran dua massa air, yakni air tawar dan air laut. Tujuan penelitian untuk mengetahui komposisi dan kelimpahan larva ikan, mengetahui perbedaan struktur komunitas pada saat pasang dan surut. Metode yang di gunakan adalah metode survei yang dilaksanakan pada bulan Mei 2018 di Muara sungai Morosari Sayung, Demak. Sampling dilakukan pada 3 stasiun dengan kondisi pasang dan surut. Variabel yang diukur antara lain Komposisi, Kelimpahan Larva ikan dan Struktur komunitas pada saat pasang dan surut. Hasil penelitian didapatkan Larva ikan pada saat pasang di stasiun I sebanyak 43 ind, stasiun II diperoleh larva  ikan sebanyak 22 ind dan stasiun III sebanyak 34 ind. Hasil penelitian didapatkan pada saat surut di stasiun I sebanyak 24 ind, stasiun II 22 ind dan stasiun III sebanyak 34 ind. Keseluruhan larva ikan yang tertangkap terdiri dari 10 famili yaitu Nemipteridae, Mugilidae, Gobiidae, Ambassidae, Acrididae, Chanidae, Engraulidae, Labridae, Scatophagidae dan Lactaridae. Indeks keanekaragaman pada saat pasang termasuk dalam kategori rendah dan sedang dengan nilai berkisar 0,99-1,6. Indeks keseragaman berkisar antara 0,78-0,91 maka tergolong kedalam kategori tinggi atau stabil. Nilai indeks Dominasi termasuk kedalam dominasi rendah dan sedang dengan nilai berkisar antara 0,22-0,40. Nilai indeks keanekaeragaman pada saat surut masuk dalam kategori rendah dan sedang dengan nilai berkisar 0,91-1,41. Indeks keseragaman berkisar 0,66-0,91 masuk dalam kategori stabil. Dominasi berkisar antara 0,32-0,45, dengan nilai tersebut maka dapat dikategorikan Dominasi sedang.  Estuary is a semi-closed waters located in the downstream part of the river and still in contact with the sea, allowing for mixing of two water masses, namely fresh water and sea water. The purpose of this research is to find out the composition and abundance of fish larvae, to know the differences in community structure during high and low tide levels. The method used in this research is a survey method conducted in May 2018 in the river estuary of Morosari Sayung, Demak. Sampling was carried out at 3 tidal and low tide stations. Variables measured include Composition and Abundance of fish larvae and community structures during highs and low tide level. The research result showed that 43 ind larvae at high tide at station I, were 22 ind at stations II, were obtained and 34 ind stations III. The results of the research were obtained at low tide at station I as many as 24 ind, station II 22 ind and station III as many as 34 ind. All captured fish larvae consist of 10 families namely Nemipteridae, Mugilidae, Gobiidae, Ambassidae, Acrididae, Chanidae, Engraulidae, Labridae, Scatophagidae and Lactaridae. The diversity index value at the high tide entered in the low and medium category ranged from 0.99 to 1.6. Uniformity lindex ranges from 0.78 to 0.91 in the medium category. Domination ranges from 0.22 to 0.40, with this value the entire research station into the category there is no dominance. The diversity index value at the low tide entered in the low and medium category ranged from 0.91 to 1.41. The uniformity index ranges from 0.66 to 0.91 included in the stable category. Domination ranges from 0.32-0.45 with this value can be categorized medium. 

Experimental Study on Flow Conditions of Jiaogang Ship Lock during Sluice Gate Hoist

2013 ◽  
Vol 405-408 ◽  
pp. 1458-1462
Author(s):  
Teng Wu ◽  
Jian Ding
Keyword(s):  
Water Level ◽  
Spring Tide ◽  
Main Flow ◽  
Tidal Range ◽  
Flow Conditions ◽  
Sluice Gate ◽  
Lock Chamber ◽  
Approach Channel ◽  
Lower Water Level ◽  
Ship Lock

The physical model of Jiaogang Ship Lock is established. Through model test, the flow condition in lock chamber and approach channel is studied. The results indicate when the upstream water level keeps high and the water level difference between upstream and downstream is less than 0.5 meter, the main flow oscillates less during spring tide flux and reflux in the flood year. When the upper water level is 0.96 m and during spring tide flux and reflux in the flood year, the flow is from downstream to upstream and the flow is smooth. When the upper water level is greater than lower water level, the sluice gate hoist condition is tidal range less than 0.3m in tide flux and less than 0.4m in tide reflux. Under the critical water level conditions, the Jiaogang Ship Lock sluice gate can be hoisted safely.

Tidal studies on Aldabra

1971 ◽  
Vol 260 (836) ◽  
pp. 93-121 ◽  
Keyword(s):  
Water Level ◽  
Time Lag ◽  
Spring Tide ◽  
High Water ◽  
Wire Mesh ◽  
Tidal Range ◽  
Masking Effect ◽  
Phase Lag ◽  
Central Pacific ◽  
Du Bois

The oceanic tide at Aldabra possesses a very large range for an atoll owing to the influence of the Mozambique Channel. The mean spring-tide range, expressed as 2 ( M 2 + S 2 ), is 2.74 m. This is much greater than the 0.5 m common to the majority of central Pacific atolls, and the 0.7 to 1.7 m for Indian Ocean atolls. Ten tide-recording stations were set up by members of the expedition. Foxboro—Yoxall tide-gauge records were obtained from most sites, though there are few accessible rock ledges near deep water suitable for the instrument, especially in the lagoon. Visual records were used extensively in a detailed study of the tidal system in Passe Houareau. Tidal predictions for Aldabra found in Admiralty Tide Tables possess marked lagoonal characteristics. They originate from ‘Grand Poste’, a site well within Grande Passe. It is recommended that records for Passe du Bois be taken as standard since they most closely represent the oceanic tide. Empirically derived tide-predicting graphs are presented for key stations around the atoll, using Kilindini as standard port. Reduction in tidal range is pronounced in the lagoon and is conspicuous even near the mouths of the major channels. Within Passe Houareau spring-tide amplitudes may be a mere 1.2 m only 500 m from the channel mouth where the oceanic range is 3.3 m. Time lag increases lagoonwards more rapidly at Passe Houareau than at either Passe du Bois or Grande Passe, and is greater at low water than at high because of the very shallow nature of the lagoon floor. The greatest recorded phase lag occurs at the head of Bras Cinq Cases, where high water is delayed by 4 1/4 h at major spring tides: at neaps the whole region is dry at high water. Harmonic analyses are presented for one oceanic and two lagoonal stations. Computer synthesis of neap tides in the lagoon demonstrates a monthly masking effect produced by prominent shallow water harmonics. This results in the lagoon being virtually tideless on the smallest neap tides. Strong higher harmonics are indicated by visual records for Ilot Marquoix at the eastern end of the lagoon. These are characterized by a plateau-like high water, where the level commonly remains stationary for over 3 h. Lagoon tide curves are markedly asymmetrical, and often show linear ebb profiles, indicating that the lagoon behaves as a simple water-filled basin in many areas. Drainage off lagoon platforms is slow, water level falling by only 3 to 5 cm h -1 . This results in the tide ebbing for to 10 h out of the 12 1/2 h cycle. Towards spring tides more water enters the lagoon through Passe Houareau than can drain away before the next tide. Water level gradually builds up until at major springs a foot of water covers the lagoon platform at low tide. Extreme low water coincides with neap tides. Because of this ponding effect significant differences in insolation are experienced by marine bottom communities. On oceanic platforms extreme low water coincides with spring tides and occurs at midday: in the lagoon, platforms are most exposed between 06h00 and 08h00 and are always covered at noon. The effects of solar insolation are therefore minimal throughout much of the Aldabra lagoon, but are at a maximum around the coast. Tidal currents were measured in each of the Passes. In the western channels maximum values of 1.5 m s -1 (3 knots) were recorded in Passe du Bois. In Passe Gionnet a peak ebb value of 3.7 m s -1 (7.2 knots) was attained at high springs, with 3 m s -1 (6 knots) sustained for over 2 h. Flow/ebb current reversals are rapid, and in Passe Gionnet accompanied by the development of standing waves. Many channels are floored with trains of reversing sand megaripples. Elsewhere scour is appreciable; a wire mesh shark cage on the floor of Passe du Bois being undercut by 25 cm in 2 weeks. Transitory megarippled sandbanks occur on the eastern flank of Passe Houareau, and bottom facies throughout the lagoon are sculptured by the strong tidal scour.

scholarly journals Nutrient Condition of Kampar Big River Estuary: Distribution of N and P Concentrations Drifted by Tidal Bore ”Bono”

2017 ◽  
Vol 22 (3) ◽  
pp. 137
Author(s):  
Ulung Jantama Wisha ◽  
Lilik Maslukah
Keyword(s):  
Agricultural Waste ◽  
Spring Tide ◽  
Industrial Effluent ◽  
River Estuary ◽  
Data Retrieval ◽  
Tidal Range ◽  
Anthropogenic Activity ◽  
Nutrient Distribution ◽  
Tidal Bore ◽  
Nitrate Concentrations

Due to accelerated anthropogenic activity, a significant amount of pollutants has been directly or indirectly discharged into coastal estuaries of Kampar. Nutrient pollution along the river to the estuary that adversely affects coastal and estuary ecosystem mainly originates from inland such as industrial effluent, household, and agricultural waste as well as a naturally derived pollutant from biogeochemical cycle, which is controlled by the propagation of undular bore (Bono). The purpose of this study is to determine the environmental impact of distribution of nutrients caused by the mechanism of Bono. This research employed a purposive quantitative method, the concentration of dissolved phosphate, nitrate, nitrite and ammonia was analyzed using a spectrophotometer, tidal data retrieval was measured for 30 days’ near the estuarine area, while, current flow was measured for 24 hours’ measurement. Phosphate concentrations ranged from 0.02-0.1 mg.L-1, nitrate concentrations ranged from 0.76-5.73 mg.L-1, ammonia concentrations ranged from 0.2-0.41 mg.L-1, nitrate concentrations ranged from 0.001-0.03 mg.L-1. The tidal type is mixed tide prevailing semidiurnal with tidal range reach 4.2 m during spring tide condition. At the time of Bono propagate, drastically enhance the surface elevation and directly increase the drift of velocity with the flow direction from estuary into the river upstream, that mechanism affects the nutrient distribution in Kampar river. Keywords: Bono, Fluid dynamics, Nutrient distribution, Tidal bore, Water quality

Numerical Analysis of the Influence of Sea Level Rise on Flood and Tidal Stage in the Yangtze River Estuary

2013 ◽  
Vol 807-809 ◽  
pp. 1608-1611 ◽  
Author(s):  
Tian Hu ◽  
Jie Gu ◽  
Xiao Li Wang ◽  
Dan Qing Ma ◽  
Ji Zhong Yang ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Yangtze River ◽  
High Tide ◽  
River Estuary ◽  
Tidal Range ◽  
Yangtze River Estuary ◽  
The Yangtze River ◽  
The Yangtze River Estuary ◽  
Tidal Stage

A two-dimensional numerical model was set up to simulate the tidal current of the Yangtze River Estuary with MIKE21 FM. This model has been calibrated and validated with the observed tidal level. We simulated the change of flood and tidal stage in the Yangtze River Estuary after the sea level rising by 20~60cm. The simulate results indicate that: (1)With sea level rising, the extent of rise of the high tide is greater than that of rise of low tide. Under the same sea level rise, the closer to the lower reaches of the Yangtze River Estuary, the more obvious the increase in the low tide level is, the rise of the high tide does not change significantly. (2)For the changes of the tidal range increase, under the same sea level rise, the closer to the upper reaches of the Yangtze Estuary, the greater the tidal range increase is.

Experiment Study on Force of Hoisting Triangular Gate of Ship Lock in Tidal Reach

2013 ◽  
Vol 391 ◽  
pp. 402-405
Author(s):  
Teng Wu ◽  
Jian Ding ◽  
Ling Li Wu
Keyword(s):  
Water Level ◽  
Spring Tide ◽  
High Water ◽  
Tidal Range ◽  
Water Control ◽  
Absolute Value ◽  
Tidal Reach ◽  
Lock In ◽  
Lock Gate ◽  
Ship Lock

A physical model of Jiaogang Ship Lock is established in the paper. Through model test, the force of triangular gate under the condition of opening is studied. The result shows when the upper water level is high water control and when absolute value of upper-lower tidal range is less than 0.5m during the spring tide flux and reflux in the flood season of the Yangtze River in the flood year, the ship lock gate can be opened. When the upper water level is medium water control, the absolute value of upper-lower tidal range to open the ship lock gate should be less than 0.4m. And when the upper water level is low water control, the critical tidal range value is also less than 0.5m.

scholarly journals ABRASI PANTAI DAN PENDANGKALAN KOLAM PELABUHAN JETTY PERTAMINA BALONGAN, INDRAMAYU MELALUI ANALISIS ARUS PASANG SURUT, ANGIN DAN GELOMBANG

2016 ◽  
Vol 9 (1) ◽  
pp. 15
Author(s):  
Lukman Arifin ◽  
Beben Rachmat
Keyword(s):  
Tidal Current ◽  
Current Flow ◽  
High Tide ◽  
Spring Tide ◽  
Current Data ◽  
Sediment Supply ◽  
Longshore Current ◽  
Coastal Structures ◽  
Water Based ◽  
Wave Hindcasting

Masalah utama yang terjadi di perairan sekitar kolam Pelabuhan Jetty Pertamina Balongan, Indramayu adalah abrasi dan pendangkalan. Oleh karena itu dilakukan analisis mengenai pendangkalan kolam pelabuhan dan abrasi pantai di lokasi ini dengan menggunakan data arus stasioner, trayektori arus, pasang surut dan hindcasting gelombang. Data penelitian lapangan selama satu bulan memperlihatkan telah terjadi proses pendangkalan dan abrasi pantai di sekitar area Pelabuhan Jetty Pertamina. Proses ini terjadi akibat terganggunya laju sedimen yang berasal dari selatan ke utara dan sebaliknya oleh aliran arus sejajar pantai dan arus pasang surut karena keberadaan Pelabuhan Jetty Pertamina (terganggunya kesetimbangan suplai sedimen). Kecepatan arus pasang surut pada tiga kedalaman berbeda rata-rata berkisar antara 0.168 – 0.215 m/s dan kecepatan arus terbesar sebesar 0.371 m/s terjadi pada saat spring tide. Arus pasang surut dan arus sejajar pantai secara bersinergi mempercepat terjadinya abrasi pantai dan pendangkalan kolam Pelabuhan Jetty. Laju abrasi pantai di perairan ini berdasarkan data PPPGL tahun 2003 adalah sebesar 1 – 4 m per tahun. Salah satu upaya untuk menanggulangi abrasi dan pendangkalan di kolam Pelabuhan Jetty terlebih dahulu harus di lakukan studi pemodelan. Studi pemodelan ini digunakan untuk melihat gambaran secara dinamis kondisi hidro dinamika perairan yang berhubungan dengan proses terjadinya pendangkalan dan abrasi, serta untuk menentukan tipe bangunan pantai yang sesuai. Kata kunci : pelabuhan, jetty, sedimentasi, pendangkalan, abrasi, arus, sedimen The main problem that occured around the pool of port Pertamina Jetty Balongan, Indramayu is abrasion and shoaling. Therefore an analysis of the shoaling pool of port and coastal abrasion in this location was conducted by using the stationary current data, trajectory current, tide and wave hindcasting. Data of one-month field observation shows there has been shoaling and coastal abrasion processes in the areas sorrounding port Pertamina Jetty. This process occurs due to disruption of the rate of sediment derived from south to north and vice versa by the current flow parallel to the coast and tidal current because of the presence of Pertamina Jetty port (disturbance of equilibrium sediment supply). The velocity of tidal currents on three different average depths ranging from 0.168 – 0.215 m/s and the largest flow velocity of 0.371 m/s during spring tide. The direction of static current measurement and float tracking south-southeast trending dominant at low tide and northwest-north at high tide. Tidal current and longshore current sinergies to accelerate the occurence of coastal abrasion and shoaling pool of Harbour Jetty. The rate of coastal abrasion in this water based on PPPGL data of 2003 that is 1 – 4 m/s per year. One effort to overcome abrasion and shoaling in pool Harbour Jetty should be done prior modeling studies. This modeling study is used to portraya water hydro dynamics associated with the process of shoaling and abrasion, as well as determine the appropriate types of coastal structures. Keyword : ports, jetties, sedimentation, shoaling, abrasion, currents, sediment

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