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Journal : Jurnal Ilmu dan Teknologi Kelautan Tropis

ACCURACY IMPROVEMENT ON SEA SURFACE HEIGHT ESTIMATION BASED ON WAVEFORM RETRACKING ANALYSES OF JASON-2 SATELLITE IN JAVA SEA Muhammad R. Hakim; Bisman Nababan; James P. Panjaitan
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 7 No. 2 (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 | Full PDF (476.555 KB) | DOI: 10.29244/jitkt.v7i2.11254

Abstract

A waveform created by the reflected signal from altimeter satellite in offshore is generally in ideal shape (Brown-waveform) and produces an accurate sea surface height (SSH) estimation. However, over coastal waters, the waveform shape becomes complex due to a disruption by reflected signal from land, resulting inaccurate SSH estimation. The objective of this research was to improve the accuracy of SSH estimation employing waveform retracking analyses of Jason-2 altimeter satellite data in the Java Sea during the years of 2012-2014. This study used data from the Sensor Geophysical Data Record type D (SGDR-D) from Jason-2 satellite (cycle 129 - 239) and global geoid undulation data of Earth Gravitational Model 2008 (EGM08). Waveform retracking analyses were conducted using several retracker methods. The performance of the all retrackers were examined using a world reference undulation geoid of EGM08. The results showed that the waveform retracking analyses were able to improve the accuracy of SSH estimation approximately 29.7% in the north coast and 56.4% in the south coast of total non-Brown-waveform in each region. Higher improvement percentage (IMP) of SSH estimation found in the southern coastal areas was due to a relatively smooth coastline formation in this region than in northern coastal region. There was no specific retracker that produce dominant IMP of SSH estimation. However, the  threshold 10% retracker produced better SSH estimation than the other retrackers with dominant IMP values of 57.1% (pass 051), 48.1% (pass 064), and 25.7% (pass 127). OCOG retracker the worst retracker to estimate SSH in the Java Sea.                                                                                                               Keywords: EGM08, waveform retracking, SSH, Jason-2, ocean retracker, threshold retracker
PEMETAAN HABITAT BENTIK BERBASIS OBJEK MENGGUNAKAN CITRA SENTINEL-2 DI PERAIRAN PULAU WANGI-WANGI KABUPATEN WAKATOBI La Ode Khairum Mastu; Bisman Nababan; James P Panjaitan
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 10 No. 2 (2018): 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 (2017.861 KB) | DOI: 10.29244/jitkt.v10i2.21039

Abstract

Penelitian pemetaan habitat bentik di Pulau Wangi-wangi masih sangat sedikit dilakukan, sehingga ketersediaan data spasial habitat bentik di daerah ini sangat terbatas. Penelitian ini bertujuan untuk memetakan habitat bentik perairan dangkal menggunakan citra Sentinel-2 dengan metode klasifikasi berbasis objek/OBIA dan menghitung tingkat akurasi hasil klasifikasi habitat bentik di perairan Pulau Wangi-wangi Kabupaten Wakatobi. Penelitian ini dilaksanakan di perairan Pulau Wangi-wangi, khususnya perairan Sombu Dive dan sekitarnya. Penelitian ini menggunakan data satelit Sentinel-2 dengan resolusi spasial 10x10 m2 yang diakuisisi pada tanggal 4 April 2017 dan pengambilan data lapangan dilakukan pada bulan Maret - April 2017. Klasifikasi citra dengan metode OBIA menggunakan metode contextual editing pada level 1. Level 2 menggunakan klasifikasi terbimbing dengan beberapa algoritma klasifikasi yaitu support vector machine (SVM), decision tree (DT), Bayesian, dan k-nearest neighbour (KNN) dengan input themathic layer dari data lapangan. Klasifikasi habitat bentik dilakukan pada 12 dan 9 kelas dengan penerapan optimasi skala segmentasi yaitu 1, 1,5, 2, dan 2,5. Berdasarkan metode OBIA, habitat bentik dapat dipetakan dengan tingkat akurasi sebesar 60,4% dan 64,1% pada citra klasifikasi 12 dan 9 kelas secara berturut-turut pada nilai optimum skala segmentasi 2 dengan algoritma SVM.