1,721,027 research outputs found
Anwendung adaptiver Gitter-Verfeinerung auf die Tsunami Modellierung: TsunaFLASH
No full textThe devastating Sumatra-Andaman tsunami of December 2004, is a milestone for the internationalcommunity striving to introduce measures to prevent hazards from (future) tsunamis. One of themeasures is numerical modeling which plays a key role for predictions as well as inundation mappingdevelopments.Numerical modeling has been used as a tool for analyzing and reconstructing tsunamis foralmost 40 years. Nowadays, many tsunami codes are available as open-source or free-ware andwidely used in the tsunami modeling community. Many numerical methods have been applied suchas finite difference, finite element and finite volume. The same applies to gridding methods, such asstructured and unstructured non-adaptive types.This thesis introduces a new triangle-based adaptive mesh finite element model for tsunamipropagation (and inundation) simulations. TsunaFLASH combines a numerical method developed inthe framework of the unstructured triangular element, yet non-adaptive, tsunami model TsunAWIwith adaptive mesh refinement capabilities provided by the library amatos. The methods are wellsuited for accurate resolution of localized features, maintaining computational efficiency in terms ofthe number of computations and the required memory.In this first developments of TsunaFLASH, a number of experiments have been performed fortesting. There are: An experiments on various initial conditions, from an analytical source up to acoupling to the sophisticated rupture generator RuptGen; experiments with diverse error estimatorsfor testing refinement criteria and adaptation algorithms; benchmark experiments using analyticalsolutions and field observations where the analytical solution is derived from the first benchmarkproblem from The International LongWaves reference; and the sea surface elevation in the field dataexperiment is used from the satellite tracks of Jason-1 and Topex for verification of the Sumatra-Andaman mega-tsunami 2004 event, while the water level reading of DART 23401 is used for the verification of the Andaman minor tsunami 2009.Some additional studies have been conducted to assess the physical background of tsunamissimulation and test proper supporting tools for TsunaFLASH. There experiments comprise sourcemodel reconstructions and simulations based upon these in the context of a probable worst casetsunami simulation for Padang; experiments to test the influence of different types of topographieson the inundation behavior; and an investigation of the most representative source model for theAndaman-Sumatra mega-tsunami of 2004. Finally, the ambiguity of the arrival time of the Javaminor tsunami 2009 is experimentally investigated
Adaptive Mesh Refinement Applied to Tsunami Modeling: TsunaFLASH
No full textThe devastating Sumatra-Andaman tsunami of December 2004, is a milestone for the internationalcommunity striving to introduce measures to prevent hazards from (future) tsunamis. One of themeasures is numerical modeling which plays a key role for predictions as well as inundation mappingdevelopments.Numerical modeling has been used as a tool for analyzing and reconstructing tsunamis foralmost 40 years. Nowadays, many tsunami codes are available as open-source or free-ware andwidely used in the tsunami modeling community. Many numerical methods have been applied suchas finite difference, finite element and finite volume. The same applies to gridding methods, such asstructured and unstructured non-adaptive types.This thesis introduces a new triangle-based adaptive mesh finite element model for tsunamipropagation (and inundation) simulations. TsunaFLASH combines a numerical method developed inthe framework of the unstructured triangular element, yet non-adaptive, tsunami model TsunAWIwith adaptive mesh refinement capabilities provided by the library amatos. The methods are wellsuited for accurate resolution of localized features, maintaining computational efficiency in terms ofthe number of computations and the required memory.In this first developments of TsunaFLASH, a number of experiments have been performed fortesting. There are: An experiments on various initial conditions, from an analytical source up to acoupling to the sophisticated rupture generator RuptGen; experiments with diverse error estimatorsfor testing refinement criteria and adaptation algorithms; benchmark experiments using analyticalsolutions and field observations where the analytical solution is derived from the first benchmarkproblem from The International LongWaves reference; and the sea surface elevation in the field dataexperiment is used from the satellite tracks of Jason-1 and Topex for verification of the Sumatra-Andaman mega-tsunami 2004 event, while the water level reading of DART 23401 is used for the verification of the Andaman minor tsunami 2009.Some additional studies have been conducted to assess the physical background of tsunamissimulation and test proper supporting tools for TsunaFLASH. There experiments comprise sourcemodel reconstructions and simulations based upon these in the context of a probable worst casetsunami simulation for Padang; experiments to test the influence of different types of topographieson the inundation behavior; and an investigation of the most representative source model for theAndaman-Sumatra mega-tsunami of 2004. Finally, the ambiguity of the arrival time of the Javaminor tsunami 2009 is experimentally investigated
Analisis Variabilitas Nitrat dalam Hubungan dengan El Nino Southern Oscillation (ENSO) dan Indian Ocean Dipole (IOD) di Perairan Selat Bali dan Sekitarnya: Analysis of Variability of Nitrate in Corellation with El Nino Southern Oscillation (Enso) and Indian Ocean Dipole (IOD) in The Bali Strait And Surroundings
Full text linkTingkat kesuburan perairan laut sangat terkait dengan kadar tinggi konsentrasi nutrien dalam kolom air. Nutrien menjadi tolak ukur merupakan nutrien. Selat bali dan sekitarnya merupakan wilayah kajian penelitian dengan koordinat 8°8'58"LS 114°25'7"BT. Metode yang digunakan adalah analisis dengan mengaplikasikan software ODV (Ocean Data View) dengan data yang diolah berupa data biogeokimia dan kedalaman dari website INDESO pada bulan Januari sampai dengan bulan Desember tahun 2014 hingga 2017, yang kemudian hasil dianalisis secara deskriptif.nDari hasil data dan grafik yang diperoleh diketahui bahwa dari ke empat kedalaman kadar nutrien (Nitrat) tertinggi berada pada kedalaman 53,850m, dan terendah berada di 0,505. Diantara ke tiga Zona yaitu nutrien yang paling tinggi berada di area Selat Bali dan Samudera Hindia. Sedangkan, nutrien terendah berada di area Laut Bali. Rata – rata kadar nitrat paling tinggi berada di Musim Timur karena pada musim tersebut adanya kejadian Upwelling yang menyebabkan nutrien yang ada di dasar naik ke permukaan. Nutrien juga dipengaruhi oleh fenomena ENSO dan IOD, karena adanya fenomena anomali pada angin, awan, dan SPL, yang dapat mempengaruhi perairan
Geomatics and Environmental Engineering
No full textThis research aims to investigate the morphodynamics of the Wulan River estuary in Demak Regency using the integration of multispectral remote sensing images and numerical modeling. In this study, PlanetScope for a manual-visual analysis of estuary morphodynamics and Sentinel-2 MSI Level 2A to obtain periodic total suspended solids (TSS) information for the east and west monsoon seasons. MIKE by DHI software used to develop hydrodynamic numerical modeling in order to characterize the current circulation and sediment transport model. Based on a marine cartography aspect, the obtained results illustrated that the climatological phenomenon of seasonal forcing plays a role in the development of the current circulation and indirectly influences the sediment transport. During the west season, the morphodynamics in the Wulan River estuary are much more massive and significant as compared to the east season. A projection of the deposition that results from the sediment transport is described in the bed-thickness change, this occurs in the western part of the Wulan River estuary during the east season, while the bed-thickness change occurs predominantly in the northern part during the west season (where there was previously a beach sandbar phenomenon). This was verified through multi-temporal satellite imagery that the deposition that occurs in the northern part of the Wulan River estuary during the west season is increasingly progressive and massive.Krakówwersja wydawnicz
Pemodelan Hidrodinamika 2 Dimensi Arus Dibangkitkan Angin dan Pasut Untuk Informasi Pendukung Operasi Pendaratan Amfibi (Studi Kasus Pantai Sengiap Ranai Natuna): 2 Dimensional Hydrodynamic Modeling of Wind and Tidal Generated Currents for Supporting Information for Amphibious Landing Operations (Case Study of Sengiap Ranai Natuna Beach)
No full textOperasi Pendaratan amfibi merupakan kegiatan operasi militer ofensif maupun defensif dari laut menggunakan kapal pendarat untuk memproyeksikan kekuatan darat disuatu pesisir pantai dengan kemungkinan terdapat area musuh. Pendaratan pasukan amfibi ini diakui sebagai semua manuver militer yang paling kompleks karena mengerahkan seluruh kekuatan kapal pendarat maupun pendukung yang berasal dari semua sektor pertahanan militer. Informasi tentang daerah dengan waktu yang efektif untuk melakukan pendaratan sangat penting demi keberhasilan suatu operasi. Berkaitan dengan operasi ini, perlu dibuat sebuah penelitian untuk mengetahui karakteristik dengan menampilkan kondisi hidrodinamika daerah pendaratan tersebut. Salah satu caranya dengan pendekatan pemodelan numerik, analisa karakteristik arus laut untuk pendaratan dengan mengkonversi arah dan kecepatan angin menggunakan sofware pemodelan Mike21 selanjutnya di overlay ke dalam perangkat lunak Arcgis 10.4.1 dengan tampilan animasi diharapkan mampu menggambarkan area tersebut dengan melakukan pergerakan pendaratan kapal pasukan untuk manuver didaerah yang telah digunakan dengan menampilkan 7 parameter sebagai data output dari Flow Model Fm per 3 jam di 4 musim yang berbeda dalam satu tahun yang digunakan sebagai informasi penting untuk melakukan pendaratan
Pembangunan Purwarupa Alat Ukur Gelombang Menggunakan Sensor Tekanan Dilengkapi Telemetry : Construction of a Prototype of Wave Measurement Tool Using a Pressure Sensor Equipped with Telemetry
No full textData gelombang dan data pasang surut merupakan data yang sangat dibutuhkan dalam berbagai bidang, diantarannya dalam bidang hidrografi, oseanografi, proyek rekayasa, perikanan, pariwisata dan penanggulangan bencana. Hal ini menimbulkan konsekuensi atas ketersediaan alat ukur gelombang dan pasang surut dalam skala besar, praktis, ekonomis, gelombang dan pasang surut sensor pressure yang dilengkapi dengan telemetri sehingga dapat memenuhi kebutuhan tersebut serta mewujudkan kemandirian teknologi dalam negeri. Pembuatan alat ukur tersebut dilaksanakan dengan menggunakan microcontroller Arduino mega, sensor tekanan silikon piezoresistif TMC19-100 bar G1602s, serta dilengkapi perangkat telemetri yang menggunakan Modem GSM. Alat di ujicoba di pantai putri duyung ancol selama 3 hari mulai tanggal 28 November sampai dengan 30 Nopember 2018 dengan alat pembanding RBR Duo dan Tide Master. Data pengamatan dari ketiga alat diolah dan dianalisa akurat dan akses data yang cepat. Dalam penelitian ini penulis bermaksud membuat prototype alat ukur dengan hasil data dibandingkan sehingga memiliki selisih dari ketiga alat tersebut yang kemudian dijadikan referensi untuk pengembangan alat kedepannya
Simulasi Pemodelan 3-Dimensi Hidrodinamika Arus Baroklinik di Perairain Selat Alor: 3-Dimensional Hydrodynamic Modeling Simulation of Baroclinic Currents in The Waters of The Alor Strait
Full text linkPerairan Selat Alor merupakan salah satu wilayah maritim yang penting di Indonesia, di mana arus baroklinik memiliki peran signifikan dalam mengatur dinamika perairan. Dalam penelitian ini, dilakukan simulasi pemodelan 3-dimensi untuk memahami perilaku hidrodinamika arus baroklinik di perairan Selat Alor. Pola, arah dan pergerakan arus pada Selat Alor memiliki pola yang hampir sama pada setiap bulannya selama periode pengamatan bulan Januari 2023, April 2023, Juli 2023, dan Oktober 2023 pada musim Barat,peralihan musim barat ke Timur,Musim Timur,serta peralihan Musim Timur ke Barat dengan arah pergerakan dominan menuju utara, kecuali yang terjadi pada Bulan April yaitu arus cenderung mengarah ke arah Selatan hal ini di karenakan beberapa faktor, termasuk perubahan musiman dalam pola angin, suhu permukaan laut, dan fenomena atmosferik lainnya. Nilai rata-rata kecepatan keseluruhan perairan Selat Alor yaitu sekitar 0,804462337 m/s. Arus ini cenderung mengalir ke arah utara, dengan pola aliran yang mengalami defleksi akibat efek Coriolis. Distribusi salinitas arus permukaan di perairan Selat Alor pada setiap Musim Barat cenderung merata yaitu sekitar 34,400 ppt-34,425 ppt. Sementara musim peralihan barat ke timur salinitas lebih tinggi di daerah selatan selat dengan nilai rata-rata 34,04 ppt-34,24 ppt. Pada musim timur sama seperti musim peralihan barat ke timur yaitu cenderung tinggi di area selatan Selat Alor dengan nilai sekitar 33,92 ppt-34,32 ppt. Sedangkan pada musim peralihan timur ke barat yaitu ke arah utara Selat Alor, meningkatkan salinitas di wilayah tersebut dengan nilai rata-rata sekitar 34,43 ppt-34,50 ppt. Sementara untuk distribusi temperatur keseluruhan di perairain Selat Alor rata-rata sekitar 12°C-16°C.Selain itu, simulasi juga mengungkapkan adanya pola aliran sekunder dan turbulensi yang terbentuk akibat interaksi kompleks antara arus utama dengan topografi dasar laut
THE INFLUENCE OF SWIMMING LAYER AND SUB-SURFACE OCEANOGRAPHIC VARIABLES ON CATCH OF ALBACORE (Thunnus alalunga) IN EASTERN INDIAN OCEAN
Full text linkThe current study highlighted the relationship between the number of ALB catch, swimming layer and sub-surface oceanographic variables (temperature, dissolved oxygen, salinity, nitrate, phosphate and silicate) in Eastern Indian Ocean. This data used in this study were based on the Research Institute for Tuna Fisheries (RITF) observer program in Benoa from 2010-2013. This paper presents the information about vertical distribution of Albacore and its relations to sub surface oceanographic variables (SSOV). Results show that the optimum catch of albacore occurred at depth of 118 to 291 m with the average temperature between 12.41-20.47 °C, dissolved oxygen 3.24-4.68 ml/l , salinity 34.78-35.01 psu, nitrate 6.78-17.50 µ mol/l, phosphate 0.62-1.27 µ mol/l and silicate 10.06-24.77 µ mol/l. The highest catches of albacore are mostly at depth of 156 m (hook number 2 and 11) with the average temperature 18.71°C, dissolved oxygen 4.68 ml/l, salinity 34.78 psu, nitrate 10.71 µ mol/l, phosphate 0.86 µ mol/l and silicate 15.95 µ mol/l. The highest influence of swimming layer and sub-surface oceanographic variable to the number of ALB catch contained at depth of 291 m of albacore swimming layer with coefficient correlation ( r ) 0.934 and determination coefficient ( R2) 0.872. The lowest influence of swimming layer and sub-surface oceanographic variable to the number of ALB catch contained at depth of 156 m of albacore swimming layer with coefficient correlation ( r ) 0.528 and determination coefficient ( R2) 0,279. The relationship between swimming layer and sub-surface oceanographic variable on catch of ALB tuna was low (<0.500).
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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