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All Journal Jurnal Ilmu-Ilmu Perairan dan Perikanan Indonesia Jurnal Teknik Sipil The International Journal of Remote Sensing and Earth Sciences (IJReSES)
Safwan Hadi
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Civil Engineering, Building, Construction & Architecture Earth & Planetary Sciences

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Studi Dinamika Ekosistem Perairan Di Teluk Lampung: Pemodelan Gabungan Hidrodinamika-Ekosistem Alan Frendy Koropitan; Safwan Hadi; Ivonne M. Radjawane; Ario Damar
Jurnal Ilmu-Ilmu Perairan dan Perikanan Indonesia Vol. 11 No. 1 (2004): Juni 2004
Publisher : Institut Pertanian Bogor

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (762.003 KB)

Abstract

Penelitian ini bertujuan untuk mengkaji dinamika ekosistem perairan di Teluk Lampung dengan menggunakan gabungan model hidrodinamika-ekosistem dengan pendekatan numerik. Secara umum, hasil simulasi pola arus residu M2 cenderung masuk dari mulut teluk sebelah barat, sebagian terus memasuki sampai kepala teluk dan sebagian keluar kembali dari mulut teluk bagian timur. Selain itu, terlihat pula adanya suatu eddy yang mengalir berlawanan arah jarum jam di sekitar kepala teluk. Pola penyebaran masing-masing kompartimen ekosistem hasil model memiliki kesamaan dengan hasil pengamatan di lapangan, serta konsisten dengan pola arus residu M2. Pengaruh suplai dari sungai, interaksi antara proses biologis seperti produktifitas primer, sekunder (pemangsaan), kematian alami plankton, serta proses dekomposisi oleh bakteri belum begitu berperan dalam neraca dan standing stock ekosistem di Teluk Lampung. Peranan suplai dari laut lebih dominan dibanding dengan proses-proses biokimiawi yang berinteraksi di dalam teluk. Hasil perhitungan tingkat efisiensi aliran energi dari proses dekomposisi dan produksi urine zooplankton ke produktifitas primer mengalami kehilangan sebesar 30.48 %, sementara dari produktifitas primer ke produktifitas sekunder (pemangsaan) mengalami penambahan 17.24 %.Kata kunci: dinamika ekosistem, Teluk Lampung, gabungan model hidrodinamika-ekosistem, arus residu M2.
Dinamika Seas dan Swell dari Laut China Selatan ke Teluk Jakarta: Studi Kasus Kejadian Badai Hagibis, November 2007 Nining Sari Ningsih; Arief Rachman; Safwan Hadi; Farrah Hanifah
Jurnal Teknik Sipil Vol 26 No 1 (2019)
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jts.2019.26.1.8

Abstract

Karakteristik dinamika seas dan swell di sepanjang perairan Laut China Selatan-Teluk Jakarta pada waktu terjadi Badai Hagibis (18"“27 November 2007) dikaji dengan menggunakan metode pemodelan spektrum gelombang untuk mengetahui kontribusi gelombang yang dibangkitkan angin (gelombang angin) terhadap kejadian rob tanggal 25 November 2007 di pantai utara Jakarta. Pada penelitian ini, dilakukan pula uji coba simulasi model spektrum gelombang yang mengacu pada kedalaman tetap (batimetri) dan pada kedalaman total (jumlah batimetri dan pasang surut astronomis) untuk mengetahui pengaruh pasang surut astronomis terhadap hasil simulasi model gelombang yang dibangkitkan angin. Hasil simulasi menunjukkan bahwa gelombang angin di Teluk Jakarta pada tanggal 25 November 2007 didominasi oleh swell dengan tinggi gelombang ~11 cm yang diduga berasal dari Laut China Selatan sebagai daerah pembangkitan badai.Characteristics of seas and swell dynamics along South China Sea-Jakarta Bay waters during Cyclone Hagibis passage (18"“27 November 2007) have been studied using a spectral wave model to understand the magnitude of wind wave contribution to flooding event on November 25, 2007 along the northern coast of Jakarta. In this study, the model simulation was conducted using two kinds of water depth input, namely fixed water depth and timevarying water depths resulting from tides in order to obtain a better understanding of tidal influence on wind wave simulations. The simulated result shows that wind wave in the Jakarta Bay was dominated by swell with significant wave height of ~11 cm. It was expected that the swell propagated from the South China Sea as a storm generating area.
THREE-DIMENSIONAL SIMULATION OF TIDAL CURRENT IN LAMPUNG BAY: DIAGNOSTIC NUMERICAL EXPERIMENTS Alan Frendy Koropitan; Safwan Hadi; Ivonne M.Radjawane
International Journal of Remote Sensing and Earth Sciences Vol. 3 (2006)
Publisher : BRIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.ijreses.2006.v3.a1205

Abstract

Princeton Ocean Model (POM) was used to calculate the tidal current in Lampung Bay using diagnostic mode. The model was forced by tidal elevation, which was given along the open boundary using a global ocean tide model-ORITIDE. The computed tidal elevation at St. 1 and St 2 are in a good agreement with the observed data, but the computed tidal current at St 1 at depth 2 m is not good and moderate approximation is showed at depth 10 m. Probably, it was influenced by non-linier effect of coastal geometry and bottom friction because of the position of current meter, mooring closed to the coastline. Generally, the calculated tidal currents in all layers show that the water flows into the bay during flood tide and goes out from the bay during ebb tide. The tidal current becomes strong when passing through the narrow passage of Pahawang Strait. The simulation of residual tidal current with particular emphasis on predominant contituent of M2 shows a strong inflow from the western part of the bay mouth, up to the central part of the bay, then the strong residual current deflects to the southeast and flows out from the eastern part of the bay mouth. This flow pattern is apparent in the upper and lower layer. The other part flows to the bay head and froms an antic lockwise circulation in the small basin region of the bay head. The anticlockwise circulations are showed in the upper layer and disappear in the layer near the bottom.
INTERNAL WAVES DYNAMICS IN THE LOMBOK STRAIT STUDIED BY A NUMERICAL MODEL NINING SARI NINGSIH; RIMA RAHMAYANI; SAFWAN HADI; IRSAN S. BROJONEGORO
International Journal of Remote Sensing and Earth Sciences Vol. 5 (2008)
Publisher : BRIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.ijreses.2008.v5.a1226

Abstract

A baroclinic 3D hydrodynamic model with the non-hydrostatic approximation called Massachusetts Institute of Technology Global Circulation Model (MIT gcm) has been applied to simulate the generation of internal tidal bores and their disintegration into internal solitary waves in the Strait of Lombok. Numerical simulation have been carried out by incorporating seasonal variations of the stratification of the water body, which exist during the first transitional monsoon, the east monsoon, the second transitional monsoon, and the west monsoon. Our simulation yields the results that the existence of the sill at the southern part of the Lombok Strait, strong tidal flow, and a stratified fluid, play an important role in forming some short of divergence and convergence area as an indication of the birth of internal waves, which are simulated on the both sides of the sill. The simulated results reproduce reasonably well the basic features of internal waves in the Strait of Lombok as captured by the Synthetic Aperture Radar (SAR) from the European Remote Sensing (ERS) satellites ERS 1 and ERS 2, such as a north-south asymmetry, propagation speeds, average amplitudes and wavelengths, and solution packets. Similiar to observations made by National Oceanic and Atmospheric Administration (NOAA) satellites, the simulation results also showed the intrusion of warmwater from thePacific Ocean into the Indian Ocean and the exitence of well-developmed thermal plume at south of the sill. Seasonal variations of interface depth of thermocline and the density difference between the stratified layers influence magnitudes of the amplitudes and wavelengths of the internal waves and solitons, and the distance of thermal plume in the Lombok Strait. It is found that during the monsoon transition periods and the west monson, the amplitudes of internal waves and solitons at the southern part of the strait is apparently larger than those at the northern one, whereas during the east monsoon, the wave amplitudes is large north of the sill than south of it. Meanwhile, the propagation speeds of northward propagating internal solitary waves (0.71-2.67m per s) are stronger than southward propagating ones (0.21-1.53 m per s) throughout the monsoon periods.
Co-Authors Alan Frendy Koropitan Arief Rachman Ario Damar Farrah Hanifah IRSAN S. BROJONEGORO Ivonne M. Radjawane Ivonne M.Radjawane Nining Sari Ningsih RIMA RAHMAYANI