scholarly journals Pasang Surut, Arus dan Gelombang Berdasarkan Data Pengukuran Acoustic Doppler Current Profiler di Perairan Pulau Cilik, Karimunjawa

2020 ◽  
Vol 9 (1) ◽  
pp. 37-44
Author(s):  
Elis Indrayanti ◽  
Diah Permata Wijayanti ◽  
Hendry Syahputra Ropinus Siagian
Keyword(s):  
Coral Cover ◽  
Measurement Data ◽  
Acoustic Doppler Current Profiler ◽  
Ocean Currents ◽  
Time Interval ◽  
Live Coral ◽  
Actual Measurement ◽  
M 10 ◽  
Current Profiler ◽  
Sample Rate

Pulau Cilik merupakan gugusan pulau di Karimunjawa yang menjadi salah satu destinasi wisata bahari di Indonesia. Perairan ini kaya akan terumbu karang dan ikan berwarna-warni dengan  tutupan karang hidup yang masih tinggi. Proses hidrodinamika seperti pasang surut, arus laut dan gelombang laut secara langsung maupun tidak langsung berpengaruh terhadap kondisi terumbu karang, oleh karena itu penelitian ini perlu dilakukan. Tujuan penelitian adalah untuk mengetahui karakteristik pasang surut, arus laut dan gelombang berdasarkan data pengukuran Acoustic Doppler Current Profiler (ADCP) di Perairan Pulau Cilik, Karimunjawa. Pengukuran dilaksanakan selama 7x24 jam dengan interval waktu 600 dt dan sample rate 300 dt. Posisi ADCP pada -5.8177°S  dan 110.5096°E. Kedalaman total pengukuran 14 m dengan kedalaman aktif pengukuran 12 m, yang terbagi menjadi 6 lapisan kedalaman yaitu 2 m, 4 m, 6 m, 8 m, 10 m, dan 12 m.  Hasil pengukuran menunjukkan bahwa Perairan Pulau Cilik, Karimunjawa memiliki tipe pasang surut campuran condong harian tunggal dengan nilai formzahl sebesar 2.55. Kecepatan arus bervariasi dengan rata-rata pada seluruh lapisan antara 5.57–6.35 cm/dt, sedangkan arahnya bi-directional yaitu memiliki dua muka arah (timur dan barat-barat daya). Tinggi dan periode gelombang yang didapatkan pada saat pengamatan relatif kecil. Cilik Island Waters in Karimunjawa is one of the marine tourism destinations in Indonesia. These waters are rich in coral reefs and colorful fish with high live coral cover. Hydrodynamic processes as tides, ocean currents, and waves influence the performance of coral reef through direct or indirect effects. Therefore this research needs to be done. The purpose of this study was to determine the characteristics of tides, ocean currents, and waves based on Acoustic Doppler Current Profiler (ADCP) measurement data in Cilik Island Waters, Karimunjawa. Measurements were carried out for 7 x 24 hours (2 April 2017 - 9 April 2017) with a time interval of 600 s and a sample rate of 300 s. The ADCP position is -5.8177 ° S and 110.5096 ° E. The total depth is 14 m with an actual measurement depth of 12 m, which is divided into 6 layers of depth namely 2 m, 4 m, 6 m, 8 m, 10 m, and 12 m. Result shown that  Cilik Island, Karimunjawa, have a single mixed daily tidal type with a formzahl value of 2.55. Current velocity varies with the average in all layers between 5.57-6.35 cm/s, while the direction is bi-directional, which has two faces (east and west-southwest). The height and wave period obtained at the time of observation are relatively small. 

scholarly journals Application of Stage-Fall-Discharge Rating Curves to a Reservoir Based on Acoustic Doppler Velocity Meter Measurement Data

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2443
Author(s):  
Yeonsu Kim ◽  
Sungryul Oh ◽  
Seungsoo Lee ◽  
Jisun Byun ◽  
Hyunuk An
Keyword(s):  
Hydraulic Structure ◽  
Measurement Data ◽  
Acoustic Doppler Current Profiler ◽  
Doppler Velocity ◽  
Rating Curve ◽  
Gate Operation ◽  
Current Profiler ◽  
Specific Discharge ◽  
Rating Curves ◽  
Floating Objects

The applicability of the stage-fall-discharge (SFD) method in combination with acoustic Doppler velocity meter (ADVM) data, upstream of a hydraulic structure, specifically, the Sejong-weir located in the Geum River, Korea, was examined. We developed three rating curves: a conventional simple rating curve with the data measured using an acoustic Doppler current profiler (ADCP) and floating objects, an SFD rating curve with the data measured using the ADCP and floating objects, and an SFD rating curve with the data measured using an ADVM. Because of the gate operation effect, every rating curve involved many uncertainties under 1000 m3/s (3.13 m2/s, specific discharge). In terms of the hydrograph reconstruction, compared with the conventional simple rating curve, the SFD developed using ADVM data exhibited a higher agreement with the measured data in terms of the pattern. Furthermore, the measured discharge over 1000 m3/s primarily ranged between 97.5% and 2.5% in the graph comparing the ratio of the median and observed discharge. Based on this experiment, it is confirmed that the SFD rating curve with data to represent the backwater effect, such as ADVM data, can reduce the uncertainties induced by the typical rating curve

Comparison of ADCP measurements to Kuroshio current flow simulations for ocean current turbines

2021 ◽  
pp. 147509022110236
Author(s):  
John Imamura ◽  
Ken Takagi ◽  
Shigeki Nagaya ◽  
Masayuki Shimizu
Keyword(s):  
Numerical Simulations ◽  
Time Domain ◽  
Current Flow ◽  
Measurement Data ◽  
Acoustic Doppler Current Profiler ◽  
Kuroshio Current ◽  
Ocean Model ◽  
Ocean Currents ◽  
Ocean Current ◽  
Flow Profile

Numerical simulations are compared to field measurements of ocean currents in the Tokara Strait in this work. The Kuroshio Current flows through this strait and an ongoing ocean current turbine device is under development to harness its energy. The usefulness for engineering design input of modeling flow conditions for a large domain in space and time motivates the use of the numerical simulations. Confidence in the accuracy of the simulations can be provided from this comparison to Acoustic Doppler Current Profiler (ADCP) observations during the summer of 2018 at four locations. Numerical simulations of ocean currents which overlap in time with the field observations are presented in an attempt to compare the data on a time-domain basis. The simulations were produced using a Princeton Ocean Model based JCOPE-T-Tokara500 model. The analysis describes the capability of the numerical model to match the flow profile throughout the water column in the time domain and on a statistical basis using histograms and rose diagrams. While instances of speed peaks in the measurement data possibly representing internal waves did not readily appear in the simulation, overall the analysis supports the continued use of simulation current flow for project design input.

scholarly journals Identifikasi Arus Pasang Surut di Perairan Kemujan, Karimunjawa Berdasarkan Data Pengukuran Acoustic Doppler Current Profiler

2021 ◽  
Vol 24 (2) ◽  
pp. 247-254
Author(s):  
Elis Indrayanti ◽  
Denny Nugroho Sugianto ◽  
Purwanto Purwanto ◽  
Hendry Syahputra Ropinus Siagian
Keyword(s):  
Tidal Current ◽  
Acoustic Doppler Current Profiler ◽  
Tidal Currents ◽  
Residual Current ◽  
Least Square ◽  
Ocean Currents ◽  
Velocity Data ◽  
Raw Data ◽  
Current Profiler ◽  
X 24

Ocean currents are dynamic hydro-oceanographic parameters which is play an important role in the transport of nutrients, larvae, sediment, and so on. Therefore, the identification of ocean currents including velocity, direction, sea level and the type of currents important to be studied. The research was conducted in Kemujan Water, Karimunjawa. Data for this research is based on velocity data measured using the Acoustic Doppler Current Profiler (ADCP) for 3 x 24 hours. Furthermore, the raw data of the measurement are analyzed using least square methods to obtain the characteristic of tidal current. The total current is separated into tidal currents and residual current (non-tidal currents). Result shown that the characteristic of current in Kemujan Water, Karimunjawa was tidal current. Tidal current moves bi-directional, toward the northeast and the southwest.. Arus laut merupakan parameter hidro-oseanografi yang dinamis dan mempunyai peran penting dalam transpor nutrien, larva, material, dan lain sebagainya. Oleh karena itu identifikasi arus laut meliputi kecepatan, arah, elevasi muka air laut dan tipe arus laut perlu untuk dikaji. Penelitian dilaksanakan di Perairan Kemujan  yang merupakan salah satu gugusan pulau di Karimunjawa. Data  yang dianalisa merupakan data kecepatan arus hasil pengukuran langsung menggunakan Acoustic Doppler Current Profiler (ADCP) selama 3x24 jam. Selanjutnya raw data hasil pengukuran diolah dengan metode least square untuk mengetahui karakteristik arus. Arus total dipisahkan menjadi arus pasang surut dan arus non-pasang surut (residu). Hasil penelitian menunjukkan bahwa prosentase arus pasang surut lebih besar dari arus residu, sehingga arus di Perairan Kemujan, Karimunjawa teridentifikasi sebagai arus pasang surut. Arus  bergerak secara bertolak belakang (bi-directional) yaitu pada saat surut menuju pasang arah arus menuju ke timur laut dan pada saat pasang menuju surut arah arus menuju ke barat daya.

VM-ADCP backscatter data management using QGIS

2020 ◽  
Author(s):  
Paola Picco ◽  
Roberto Nardini ◽  
Sara Pensieri ◽  
Roberto Bozzano ◽  
Luca Repetti ◽  
...  
Keyword(s):  
Acoustic Doppler Current Profiler ◽  
Relevant Information ◽  
Ocean Currents ◽  
Acoustic Backscatter ◽  
Ligurian Sea ◽  
Current Profiler ◽  
High Backscatter ◽  
Set Up ◽  
High Resolution Bathymetry ◽  
Sampling Set

<p>VM-ADCP (Vessel Mounted Acoustic Doppler Current Profiler) are regularly operating on board of several research vessels with the aim of providing 3-D ocean currents fields. Along with ocean currents, these instruments also measure acoustic backscatter profile on a known frequency, that can be of great advantages for other environmental investigations such as the zooplankton migrations. The presence of zooplankton can be detected by a variation of acoustic backscatter changing  with the depth at a periodic (diurnal or semidiurnal) variability, related to the vertical  migration of these organisms. GIS has proven to be a powerful tool to manage the huge amount of VM-ADCP backscatter data obtained during the oceanographic campaigns. Moreover, this allows to extract relevant information on zooplankton distribution and abundance, even when the monitoring strategy of the experiment does not completely meet the temporal and spatial resolution required for these studies. The application here described has been developed on QGIS and tested on the Ligurian Sea (Mediterranean Sea). In order to obtain the comparability of data from instruments operating at different frequencies and sampling set-up, echo intensity data are converted into volume backscatter strength and corrected for the slant-range. Using high-resolution bathymetry rasters acquired and processed by the Italian Hydrographic Institute, allows to discard the anomalous high backscatter values due to presence of the bottom. Another advantage of the GIS is the possibility to easily identify night-collected data from the daily ones and their spatial distribution, as well as those from the surface and the deeper layer. All the possible combinations can be then visualised and analysed.</p>

scholarly journals Pengaruh laju sedimentasi terhadap tutupan terumbu karang di perairan Kota Daruba, Kabupaten Pulau Morotai

DEPIK ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 193-199
Author(s):  
Kismanto Koroy ◽  
Djainudin Alwi ◽  
Novaldo Geri Paraisu
Keyword(s):  
Sediment Trap ◽  
Coral Cover ◽  
Marine Ecosystem ◽  
Measurement Data ◽  
Live Coral ◽  
Rate Analysis ◽  
Invertebrate Animals ◽  
Reclamation Area ◽  
Sample Testing ◽  
The City

The coral reef is one of the invertebrate animals that inhabit the marine ecosystem with various aquatic biota. Physical environmental factors including sedimentation, strongly influence coral growth. This study aimed to analyze the percentage of coral cover and the sediment rates in the reclamation area of Daruba City, Morotai Island Regency. This research was carried out in November 2019 using the LIT method to calculate the percentage of coral cover and sediment trap to retrieve sedimentation data. The sediment trap was placed in the bottom waters for 14 days. Stratified filtering was used to separate the sediment, and analytical scales were used to measure dry sediment weight in grams. Sediment sample testing was conducted in the laboratory of the Faculty of Fisheries and Marine Sciences, Khairun University, Ternate. Measurement data were analyzed to calculate the percentage of coral cover and sediment rate analysis. The analysis showed that the percentage of live coral cover was in the range of 10.8 - 20.52%, this value indicates the condition of coral reefs in the waters of the village of Daruba and the waters of the reclaimed development area of the city of Daruba were in the poor category. Sedimentation rate in the reclamation area of the city of Daruba were 307,34 - 492,27 (g /cm2 /day).Keywords: Cover the reef, The rate of sediment, Morotai ABSTRAKTerumbu karang merupakan salah satu hewan avertebrata yang mendiami ekosistem dengan berbagai biota perairan. Pertumbuhan karang sangat dipengaruhi oleh faktor fisik lingkungan, salah satunya adalah sedimen. Tujuan penelitian ini yaitu menganalisis persentase tutupan karang dan menganalisis laju sedimen di area reklamasi kota Daruba Kabupaten Pulau Morotai. Penelitian ini dilakukan pada bulan November 2019 dengan menggunakan metode (LIT) untuk menghitung persentase tutupan karang dan pengambilan data sedimen menggunakan alat sediment trap yang ditempatkan di dasar perairan selama 14 hari. Selanjutnya dilakukan penyaringan bertingkat dan pengukuran berat kering sedimen dalam satuan gram dengan timbangan analitik. Pengujian sampel sedimen dilakukan di laboratorium Fakultas Perikanan dan Ilmu Kelautan Universitas Khairun Ternate. Data pengukuran dianalisis untuk menghitung persentase tutupan karang, dan analisis laju sedimen. Hasil analisis menunjukan persentase tutupan karang hidup berada pada kisaran 10,8 - 20,52%, nilai tersebut menunjukan kondisi terumbu karang di perairan desa Daruba dan area perairan pembangunan reklamasi kota Daruba termasuk dalam kategori buruk. Laju sedimentasi di perairan area reklamasi kota Daruba sebesar 307,34 - 492,27 (g/cm2/hari).Kata kunci: Tutupan karang, Laju sedimen, Morotai

scholarly journals Living coral cover and genera diversity of coral Scleractinia in eastern coastal of Minahasa Regency, North Sulawesi

2019 ◽  
Vol 6 (2) ◽  
pp. 45
Author(s):  
Ivone F Pakasi ◽  
Lawrence J.L Lumingas ◽  
Rene Ch Kepel ◽  
Arie B Rondonuwu
Keyword(s):  
Coral Reefs ◽  
Coastal Waters ◽  
Coral Cover ◽  
Shannon Index ◽  
Eastern Coast ◽  
Live Coral ◽  
North Sulawesi ◽  
M 10 ◽  
Live Coral Cover ◽  
Line Intercept

Title (Bahasa Indonesia): Tutupan karang hidup dan keanekaragaman genera karang Scleractinia di Pantai Timur Kabupaten Minahasa, Sulawesi Utara The coastal waters east of Minahasa Regency of North Sulawesi Province is one of the areas of water that have the potential to be used as Marine Protected Areas. This study provides information on the condition of coral reefs on the eastern coast of Minahasa Regency, especially in Kamenti and in Toloun. Sampling withSCUBA was conducted using lifeform categories and transects in the form of a 50 m measuring tape with 'Line Intercept Transect' techniqueat thedepthsof 5 m, 10 m and 15 m. The condition of coral reefs in the eastern coastal waters of Minahasa Regency is generally 'good'. The percentage of coral cover in Kamenti was categorized'good', while in the waters Toloun are in a state of 'average'. Genera richness on both sites can be quite high, intotal there are44 genera with 35 genera in Kamenti and 38 genera in Toloun. Kamenti station with the depth of 15 m hasthe highest conservation value because in addition to having the highest number of genera (32 genera), it has also the highest Shannon index (3.35), the highest genera richness index (8.29), the highest genera evenness index (0, 97) and the lowest dominance index (0.12). There is no apparent correlation between the percentage of live coral cover with the number of genera or the Shannon index. But the high percentage of live coral cover is not always identical with the high genera richness; the maximum genera richness is at the intermediatecover level.Perairan pantai sebelah timur Kabupaten Minahasa Provinsi Sulawesi Utara merupakan salah satu kawasan perairan yang berpotensi untuk dijadikan Kawasan Konservasi Perairan. Penelitian ini memberikan informasi tentang kondisi terumbu karang di pantai timur Kabupaten Minahasa khususnya di Kamenti dan di Toloun. Sampling dengan menggunakan SCUBA dilakukan dengan metode kategori lifeformdan menggunakan transek berupa pita meteran sepanjang 50 m dengan teknik ‘Line Intercept Transect‘  pada kedalaman 5 m, 10 m dan 15 m. Kondisi terumbu karang di perairan pantai timur Kabupaten Minahasa umumnya ‘baik’. Persentase tutupan karang batu di Kamenti berada pada kategori ‘baik’ sedangkan di perairan Toloun berada pada kondisi ‘sedang’. Kekayaan genera pada kedua lokasi penelitian dapat dikatakan cukup tinggi yakni secara total terdapat 44 genera dengan masing-masing 35 genera di Kamenti dan 38 genera di Toloun. Stasiun Kamenti kedalaman 15 m adalah yang paling tinggi nilai konservasinya karena selain memiliki jumlah genera terbanyak (32 genera), juga memiliki indeks Shannon tertinggi (3,35), indeks kekayaan genera tertinggi (8,29), indeks kemerataan genera tertinggi (0,97) dan indeks dominasi terendah (0,12). Tidak terdapat hubungan yang nyata antara persentase tutupan karang hidup dengan jumlah genera atau indeks Shannon. Tetapi persentase tutupan karang hidup yang tinggi tidak selalu indentik dengan tingginya kekayaan genera; kekayaan genera maksimun berada pada tingkat tutupan menengah.

SHALLOW WATER HABITAT MAPPING AND REEF FISH STOCK ESTIMATION USING HIGH RESOLUTION SATELLITE DATA

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Vincentius P. Siregar ◽  
Sam Wouthuyzen ◽  
Andriani Sunuddin ◽  
Ari Anggoro ◽  
Ade Ayu Mustika
Keyword(s):  
High Resolution ◽  
Reef Fish ◽  
Satellite Imagery ◽  
Field Survey ◽  
Coral Cover ◽  
Fish Density ◽  
Fish Stock ◽  
Benthic Habitat ◽  
Live Coral ◽  
Stock Estimation

Shallow marine waters comprise diverse benthic types forming habitats for reef fish community, which important for the livelihood of coastal and small island inhabitants. Satellite imagery provide synoptic map of benthic habitat and further utilized to estimate reef fish stock. The objective of this research was to estimate reef fish stock in complex coral reef of Pulau Pari, by utilizing high resolution satellite imagery of the WorldView-2 in combination with field data such as visual census of reef fish. Field survey was conducted between May-August 2013 with 160 sampling points representing four sites (north, south, west, and east). The image was analy-zed and grouped into five classes of benthic habitats i.e., live coral (LC), dead coral (DC), sand (Sa), seagrass (Sg), and mix (Mx) (combination seagrass+coral and seagrass+sand). The overall accuracy of benthic habitat map was 78%. Field survey revealed that the highest live coral cover (58%) was found at the north site with fish density 3.69 and 1.50 ind/m2at 3 and 10 m depth, respectively. Meanwhile, the lowest live coral cover (18%) was found at the south site with fish density 2.79 and 2.18  ind/m2 at 3 and 10 m depth, respectively. Interpolation on fish density data in each habitat class resulted in standing stock reef fish estimation:  LC (5,340,698 ind), DC (56,254,356 ind), Sa (13,370,154 ind), Sg (1,776,195 ind) and Mx (14,557,680 ind). Keywords: mapping, satellite imagery, benthic habitat, reef fish, stock estimation

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