Agus S. Atmadipoera, Agus S.
Oceanography Division, Department of Marine Science and Technology, Bogor Agricultural University (IPB Bogor), Bogor-Indonesia

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ANALISIS PERUBAHAN GARIS PANTAI DI WILAYAH PANTAI BARAT KABUPATEN TANAH LAUT KALIMANTAN SELATAN Darmiati; Nurjaya, I Wayan; Atmadipoera, Agus S.
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 12 No. 1 (2020): Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (514.166 KB) | DOI: 10.29244/jitkt.v12i1.22815

Abstract

Perubahan garis pantai merupakan proses yang terjadi akibat adanya pengaruh dari kondisi pantai dalam mencapai keseimbangan terhadap dampak yang terjadi dari faktor alami dan kegiatan manusia. Secara geografis, wilayah pesisir pantai Kabupaten Tanah Laut Kalimantan Selatan mencakup dua wilayah yang berada di tepi barat dan tepi selatan. Secara fisik wilayah ini dipengaruhi oleh dinamika oseanografi dari perairan Laut Jawa serta aliran Sungai Barito yang bervariasi secara musiman. Penelitian ini bertujuan untuk menganalisis perubahan garis pantai di wilayah pesisir Pantai Barat Kabupaten Tanah Laut, Kalimantan Selatan. Data yang digunakan adalah citra Landsat 8 tahun 2016 untuk menggambarkan kondisi terkini dan citra Landsat 7 tahun 2003 sebagai kondisi awal. Citra tersebut dianalisis untuk dipetakan perubahan garis pantai yang mengalami akresi atau abrasi. Hasil penelitan menunjukkan bahwa garis pantai wilayah studi mengalami perubahan, dimana sebagian telah mengalami abrasi dan sebagian garis pantai telah mengalami akresi. Secara keseluruhan garis pantai wilayah Pantai Barat Kabupaten Tanah Laut dominan mengalami akresi dibandingkan abrasi karena adanya proses sedimentasi tinggi dari sungai Barito. Tetapi, di segmen garis pantai sel 3 dan 4 telah mengalami abrasi, meskipun area ini dekat dengan estuari Sungai Barito.
GENETIC DIVERSITY OF OLIVE RIDLEY LEPIDOCHELYS OLIVACEA ASSOCIATED WITH CURRENT PATTERN IN CENDRAWASIH BAY, PAPUA Bahri, Samsul; Atmadipoera, Agus S.; Madduppa, Hawis H.
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 9 No. 2 (2017): Elektronik Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v9i2.19307

Abstract

Cendrawasih Bay is habitat for olive ridley (Lepidochelys olivacea) which is directly adjacent to the Pacific Ocean. The presence and the diversity of L. olivacea in Cendrawasih Bay has been threatened. Genetics can be the key to conservation because they play an important role in maintaining population and recovering from damage. This study aims to determine the genetic diversity of L. olivacea and its association to the current pattern in the waters of Cendrawasih Bay. Samples of L. olivacea (n=20) were collected in Kwatisore (n=8) and Yapen Island (n=12) in Cendrawasih Bay waters from August 2015 to December 2016. The molecular analysis was based on 791-bp fragment of D-Loop on the non-coding region gen. The current pattern analysis was performed through INDESO data and visualized by using Ferret software. Phylogenetic analysis showed that 2 groups of L. olivacea from a total of 2 haplotypes, whose population from Kwatisore was dispersed in two haplotypes, while the population from Yapen Island was only dispersed in one haplotype. Populations from Kwatisore showed higher variations than populations from Yapen Island. The current pattern analysis suggests that the two study sites, Kwatisore and Yapen islands are different. Both populations are only connected by the Northwest monsoon currents period that indicates a little geneflow between this populations. Thus causing differences variation between Kwatisore and Yapen Island populations genetically. Keywords: genetic diversity, current pattern, coral triangle, olive ridley
CHARACTERISTICS AND VARIABILITY OF THE FLORES ITF AND ITS COHERENCE WITH THE SOUTH JAVA COASTAL CURRENT Atmadipoera, Agus S.; Hasanah, Paradita
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 9 No. 2 (2017): Elektronik Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v9i2.19289

Abstract

Characteristics and transport variability of the Indonesian Throughflow (ITF) in the western Flores Sea (FS) and its coherency with the South Java Coastal Current (SJCC) fluctuation are investigated using validated ocean general circulation model output (2008-2014) from the INDESO configuration.  The results show that near-surface circulation in the study area is characterized by two distinct regimes:  strong southwestward ITF flow and quasi-transient anti-cyclonic eddies. Vertical dimension of ITF crossing 7.5°S is about 112 km width, 250 m depth, and high velocity core at thermocline >0.3 m/s.  Transport volume estimates along this latitude is -4.95 Sv (southward).  Bifurcation of ITF flow appears north offshore Lombok Island where -2.92 Sv flowing into Lombok Strait and the rest flowing eastward into FS. Meanwhile, vertical dimension of SJCC crossing 114°E is about 89 km width, 120 m depth, and high velocity core at sub-surface >0.35 m/s. Mean transport of SJCC is +2.65 Sv. Coherency between Flores ITF and SJCC transport variability on intra-seasonal scales is significantly high, e.g., on 30 day period (coher=0.92) and phase-lags of 0.6-day with SJCC leading to Flores ITF. This result confirmed previous studies, related to intrusion of coastally trapped Kelvin waves into Flores Sea via Lombok Strait. Keywords: Indonesian Throughflow, western Flores Sea, South Java Coastal Current
TURBULENT MIXING IN OMBAI STRAIT Suteja, Yulianto; Purba, Mulia; Atmadipoera, Agus S.
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 7 No. 1 (2015): Elektronik Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v7i1.9778

Abstract

Ombai Strait is one of the exit passages of Indonesian Throughflow (ITF) which conveys hotspot of strong internal tidal energy. Internal tide is the one of main energy which causes mixing processes in the oceans and could lead to changes in water mass characteristics. The purpose of this research was to estimate the turbulent mixing by using Thorpe analysis. Nine CTD cast were obtained for one tidal cycle (24 hours) in Ombai Strait. The results showed the average value of the turbulent mixing is 833.5 x 10-4 m2s-1, the highest found in deep homogeneous layer (2383.4x 10-4 m2s-1), followed by mixed surface layer (103.0 x 10-4 m2s-1) and thermocline (14.2 x 10-4 m2s-1). This Turbulent mixing value is much higher than the previous measurement in Indonesian Sea. This is presumably due to the strong internal tidal energy and its interaction with existing deep sill in Ombai Strait. Keywords: Indonesian throughflow (ITF), Ombai Strait, turbulent mixing
OBSERVATION OF COASTAL FRONT AND CIRCULATION IN THE NORTHEASTERN JAVA SEA, INDONESIA Atmadipoera, Agus S.; Kusmanto, Edi; Purwandana, Adi; Nurjaya, I Wayan
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 7 No. 1 (2015): Elektronik Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v7i1.9786

Abstract

The structure and spatial extent of a coastal front and circulation in the shallow (<55 m depth) northeastern Java Sea in Indonesia was investigated with a new dataset of high-resolution conductivity-temperature-depth (CTD) and along-track shipboard acoustic Doppler current profiler (SADCP) during a DIKTI-LIPI 2010 joint research cruise on R.V. Baruna Jaya 8.  The coastal front separates fresh warm coastal water derived mainly from Barito River discharge and the saline, cool Java Sea water.  The surface fresh water plume extends approximately 760 km from the Barito River estuary to the south, and its thickness varies from the surface to 10 m and 20 m depth, depending on its proximity to the fresh water source.  The front is aligned a northeast and east direction, probably related to a meandering of strong northeastward monsoon current in the eastern part of the Java Sea during the observation time. Keywords: hydrographic measurement, coastal front, Matasiri Islands, Barito River, the northwest monsoon current
SPATIAL AND TEMPORAL VARIATION OF INDONESIAN THROUGHFLOW IN THE MAKASSAR STRAIT Atmadipoera, Agus S.; Horhoruw, Selfrida M.; Purba, Mulia; Nugroho, Dwi Y.
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 8 No. 1 (2016): Elektronik Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v8i1.13221

Abstract

Using outputs of INDESO model, this study investigated vertical structure, spatial and temporal variation of the Indonesian Throughflow in Makassar Strait (M-ITF). It was shown that the main axis of persistent southward jet of M-ITF formed a unique path following the western shelf slope along the strait, which was associated with a high kinetic energy (KE) region from near-surface down to the thermocline layer. Furthermore, a drastic jump of KE appeared in the narrow and deep Libani Chan-nel (near 3°S) where the strait's width shrinks significantly, thus an elevated flow velocity was needed to maintain transport volume balance. Here, maximum southward velocity at thermocline exceeded 1.2 m/s. Spatial pattern of M-ITF can be described by the first EOF mode which accounts for 79 % of the total variances. It exhibited that contours of the flow amplitudes were similar to M-ITF path, and the largest amplitude was located near the Libani Channel. Out-of-phase relationship of the flow was found between M-ITF and eddies circulation that developed in the edges of the strait. Corresponding temporal fluctuation of the first EOF mode indicated that M-ITF variabilities varied from intra-seasonal to inter-annual scales. Annual fluctuation of M-ITF was seen from EOF mode-2 (at thermocline layer) and mode-3 at lower-thermocline. Cross-spectra analysis revealed that variability of M- ITF (e.g. on annual scale) at northern entrance was highly coherent to the fluctuations of North Equatorial Current (NEC) and Mindanao Current (MC), suggesting that variability of M-ITF was remotely influenced by the Pacific low-latitude western boundary currents. Keywords: INDESO model, Indonesian Throughflow, Makassar Strait, EOF, Cross-Spectra Analysis
UPWELLING CHARACTERISTICS IN THE SOUTHERN JAVA WATERS DURING STRONG LA NINA 2010 AND SUPER EL NINO 2015 Atmadipoera, Agus S.; Jasmine, Agitha S.; Purba, Mulia; Kuswardani, Anastasia R.T.D.
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 12 No. 1 (2020): Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v12i1.28977

Abstract

Seasonal coastal upwelling in the Southern Java waters is considered to be modulated by interannual ocean-atmosphere variability of El Nino Southern Oscillation (ENSO).  This study aims to investigate a contrast in seasonal upwelling characteristics during the La Nina 2010 and El Nino 2015 events, by using multi-datasets from INDESO model output and satellite-derived datasets. Distinct characteristics of seasonal upwelling was clearly seen. In La Nina, surface ocean-atmosphere variables were much lower than that observed in El Nino, except for precipitation rate, sea surface temperature, and sea surface height.  In La Nina, warmer (27-28°C) and a very freshwater (<33.80psu) were predominant in the upper 45m depth, concealing upwelling cooler water at subsurface. In contrast, in the El Nino, a drastic upwelled subsurface water of isotherms of 25-26°C and isohalines of 34.24-34.44psu were outcropped at the sea surface. Temperature-based upwelling index is -2°C and +4°C, demonstrating the ENSO has strongly modulated the upwelling intensity. A strong eastward South Java Coastal Current (SJCC) was found only in La Nina event.  Persistent westward Indonesian Throughflow south of 9.5°S were visible both in different ENSO events.  Estimate of Ekman transport derived from model meridional current was intervened strongly by the presence of the SJCC and the ITF.
RESPONS SUHU PERMUKAAN LAUT DAN KLOROFIL-A TERHADAP KEJADIAN ENSO DAN IODM DI WILAYAH INDO-PASIFIK TROPIS Putra, Andry Purnama; Atmadipoera, Agus S.; Pariwono, John I.
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 12 No. 1 (2020): Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v12i1.30693

Abstract

Fenomena anomali laut-atmosfer antar-tahunan dari El Nino Southern Oscillation (ENSO) dan Indian Ocean Dipole Mode (IODM) di wilayah Indo-Pasifik Tropis memberikan dampak pada ekosistem laut, hidrologi dan variabilitas iklim. Penelitian ini bertujuan untuk menganalisis pola spasial dan variabilitas temporal suhu permukaan laut (SPL) dan klorofil-a permukaan (Chl-a) terkait dengan ENSO dan IODM di Indo-Pasifik Tropis. Data deret waktu bulanan dari tahun 1980-2017 (37 tahun) diperoleh dari pusat data global, dan dianalisis menggunakan metode empirical orthogonal function (EOF). Hasil penelitian menunjukkan nilai tiga terbesar pertama dari SPL (Chl-a) menjelaskan 81,7% (76%) dari total explained variance. Struktur spasial SPL mode-1 (56%) membentuk seperti dua kutub asimetris antara timur dan barat Pasifik Tropis dengan pola yang berbeda di lepas Pantai Peru. Pola ini diduga berhubungan dengan tahun normal atau La Nina. Selanjutnya, kondisi EL Nino dan IODM diduga tergambarkan oleh SPL mode-2 (19%), dengan fase negatif dominan di atas ekuator Pasifik dan menghilangnya area upwelling di lepas Pantai Peru.