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All Journal BULETIN OSEANOGRAFI MARINA Jurnal Kelautan Tropis EnviroScienteae
Ulung Jantama Wisha
Loka Riset Sumber Daya dan Kerentanan Pesisir, Kementerian Kelautan dan Perikanan
Earth & Planetary Sciences Environmental Science

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Karakteristik Arus di Perairan Pulau Weh Pada Musim Peralihan 1 dan Kaitannya dengan Fluktuasi Suhu Permukaan Laut Ulung Jantama Wisha; Elma T. Situmeang
Buletin Oseanografi Marina Vol 9, No 2 (2020): Buletin Oseanografi Marina
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/buloma.v9i2.29543

Abstract

Posisi Pulau Weh yang strategis membuat kawasan ini unik dalam hal karakteristik oseanografi fisik. Transfer massa air di Pulau Weh sangat signifikan yang akan berdampak pada sebaran suhu perairan di sekitar kawasan pesisir. Tujuan dari penelitian ini adalah untuk mengetahui perubahan perpindahan massa air secara vertikal dan hubungannya terhadap perubahan suhu perairan. Tiga area penting diobservasi yang mewakili utara, timur, dan selatan pulau weh yakni kawasan Iboih, Ie Meulee, dan Keunekai. Tiga ADCP diinstal pada ketiga titik observasi tersebut. Secara vertikal, komponen kecepatan arus zonal dan meridional menunjukkan kecepatan yang lebih acak saat menuju ke permukaan dengan kecepatan kurang dari 0,5 m/detik. Identifikasi pasang surut elips pada seluruh stasiun membuktikan bahwa di perairan Pulau Weh, arus pasang surut dangat dominan yang mana faktor lain juga memiliki pengaruh dalam memicu perpindahan massa air di permukaan. Arah arus dominan berputar sesuai dengan kaidah Spiral Ekman dan pengaruh gaya Coriolis. Fluktuasi suhu mengikuti perubahan elevasi pemukaan dan kecepatan arus yang berkisar antara 25-35 oC. Pada penelitian ini, menunjukkan bahwa pada bagian utara (Iboih) dan selatan (Keunekai) Pulau Weh, fluktuasi suhu berlangsung secara berlawanan menyerupai “jungkat-jungkit” yang mengindikasikan peran besar dari transfer massa air dari Laut Andaman dan Samudera Hindia yang membawa massa air hangat selama musim perlaihan I. The strategic position of Weh Island makes this region is unique in terms of physical oceanography characteristics. Water mass transport in Weh Island is tremendously significant, whereby it will affect the distribution of temperature in the surrounding coastal area. This study aimed to determine the changes in vertical water mass movement and its relation to water temperature alteration. We observed three vital areas representing north, east, and south parts of Weh Island waters, namely Iboih, Ie Meulee, and Keunekai, respectively. Three ADCPs were installed at those three observation points. Vertically, the zonal and meridional current components showed a more randomly speed surface-ward with less than 0.5 m/s magnitude. Tidal ellipses identification at all stations proved that in the Weh Island, tidal current is predominant. Other factors also trigger water mass movement on the surface. Sea current dominant direction rotated as the Ekman Spiral and Coriolis force influence. Temperature fluctuation followed the surface elevation and current speed changes ranging from 25-35 oC. In this study, it shows that between northern (Iboih) and southern (Keunekai) part of Weh Island, the temperature fluctuation oppositely takes place like a “see saw” indicating the significant role of water mass transfer from the Andaman Sea and the Indian Ocean which brings warm water during the first transitional season.
Prediksi Akumulasi Sedimen Berdasarkan Survei Batimetri dan Hidrodinamika di Pesisir Teluk Mandeh, Kabupaten Pesisir Selatan, Sumatera Barat Guntur Adhi Rahmawan; Ulung Jantama Wisha; Wisnu Arya Gemilang; ilham ilham; Semeidi Husrin
Jurnal Kelautan Tropis Vol 23, No 1 (2020): JURNAL KELAUTAN TROPIS
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jkt.v23i1.6076

Abstract

Mandeh Bay is a semi-enclosed water area that there are two main estuaries, Mandeh and Nyalo River estuary. Sedimentation issue has been gotten worse due to the massive development in coastal area. This study aims to determine the sediment accumulation within Mandeh bay and its distribution patterns. The measurement of sedimentation rate applied in the Mandeh and Nyalo Estuaries. Oceanography parameters (tides and currents) recorded for 30 days measurement. The thickness of sediment accumulation was predicted by applying single beam echosounder dual frequency. The calculation of sediment volume was done using frustum formula grid 10 x10 meters. Flow model approach was also simulated to depict the distribution pattern of sediment. The thickness of sediment accumulation categorized into five spatial categories that are 0-0,3m, 0,4-0,6m, 0,7-0,9,1-1,2m, and 1,3-1,5m. The sedimentation rate in Mandeh estuary ranged from 60,85 up to 62,16 g.m-2.day-1, while in Nyalo estuary is approximately 48,86 g.m-2.day-1. The tidal current speed that is weak ranged from 0-0,05 m/s induces the sediment accumulation which mainly occurs during the neap tidal conditions. The thickness of sediment accumulation which is more than one meter identified around Mandeh River estuary and several areas near Carocok Tarusan Port where the sediment intake takes place and due to the weak current feature, it causes the increase of sedimentation in this region.  Teluk mandeh merupakan kawasan teluk semi tertutup yang mempunyai 2 muara sungai besar yaitu sungai Mandeh dan sungai Nyalo. Masalah sedimentasi menjadi semakin parah karena pengembangan wilayah pesisir yang masif. Tujuan dari penelitian ini adalah untuk mengetahui ketebalan akumulasi sedimen di dalam Teluk Mandeh dan pola distribusinya. Pengukuran laju sedimentasi dilakukan pada dua fokus area yakni muara Sungai Mandeh dan Sungai Nyalo. Pengukuran parameter oseanografi (arus dan pasang surut) dilakukan selama 30 hari pengukuran. Ketebalan akumulasi sedimen diukur menggunakan alat Single Beam Echosounder Dual Frekuensi. Perhitungan volume sedimen dihitung dengan rumus frustum grid 10x10 meter. Simulasi flow model juga dilakukan untuk mengetahui pola distribusi sedimen. Sebaran ketebalan sedimen yang dibagi dalam 5 kategori spasial yakni 0-0,3m, 0,4-0,6m, 0,7-0,9,1-1,2m, dan 1,3-1,5m. Laju sedimentasi di muara Sungai Mandeh berkisar antara 60,85 sampai 62,16 g.m-2.hari-1 dan di muara Sungai Nyalo rata-rata 48,86 g.m-2.hari-1. Kecepatan arus pasang surut yang cukup lemah berkisar antara 0-0,05 m/s menyebabkan potensi akumulasi sedimen akan berlangsung terutama saat kondisi perbani. Sedimen dengan ketebalan lebih dari 1 meter teridentifikasi di sekitar Sungai Mandeh dan beberapa Kawasan Pelabuhan Carocok Tarusan dimana asupan sedimen mendominasi. Karena karakteristik arus yang lemah, sedimentasi meningkat diwilayah ini.
PEMETAAN KERENTANAN PESISIR PULAU SIMEULUE DENGAN METODE CVI (COASTAL VULNERABILITY INDEX) Ruzana Dhiauddin; Wisnu Arya Gemilang; Ulung Jantama Wisha; Guntur Adhi Rahmawan; Gunardi Kusumah
EnviroScienteae Vol 13, No 2 (2017): EnviroScienteae Volume 13 Nomor 2, Agustus 2017
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/es.v13i2.3918

Abstract

The diversity function of coastal areas requires the increasing need for land and infrastructure that will lead to new problems such as changes in coastal morphology, the occurrence of erosion and accretion, which is supported by the population growth caused the increasing of coastal vulnerable towards hazards. This paper aims to explain the parameters affect Simeulue Island’s coastal vulnerability - beach slope, geomorphology, geology, shoreline change, mean tidal range and mean wave height - and its mapping. The data used were the bathymetry, tide, and currents, the topography of coastal morphology, LANDSAT imagery of 2000 and 2015. To determine the coastal vulnerability level, we implemented CVI (Coastal Vulnerability Index) method of 6 parameters. Finally, we found that CVI from these physical parameters ranges between 1.291to 5.00, which were classified into five classes; 1.291 – 1.826 (very low), 1.826 – 2.449 (low), 2.449 – 2.887 (moderate), 2.887 – 3.651(high), and 3.651 – 5.00 (very high).
Co-Authors Elma T. Situmeang Gunardi Kusumah Guntur Adhi Rahmawan Ilham . Ruzana Dhiauddin Semeidi Husrin Wisnu Arya Gemilang