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WAVEFORM IDENTIFICATION OF ALTIMETRY SATELLITE DATA OF SHALLOW AND DEEP WATERS IN SOUTHERN JAVA WATERS Bisman Nababan; Romdonul Hakim; Danu Adrian; Jonson L Gaol
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 6 No. 2 (2014): Electronik 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 (1417.931 KB) | DOI: 10.29244/jitkt.v6i2.9021

Abstract

ABSTRACT Waveform patterns of satellite altimetry affect the accuracy of sea surface height estimation from the satellite. The waveform patterns found in the coastal waters are generally not in the ideal form (Brown-waveform), resulting inaccurate in sea surface height estimation. The objec-tives of this research were to identify patterns of the waveform and determine their variability. Satellite altimetry Jason-2 SGDR (Sensor Geophysical Data Record) type D data located in the southern Java island waters of the year of 2013 were used and downloaded from “NOAA's Comprehensive Large Array-data Stewardship System” (www.class.ncdc.noaa.gov) . Waveform identification and analyses were conducted along the satellite pass within the distance of 0-10 km, 10-50 km, and 50-100 km form the coastline. Results showed that the highest number of non-Brown-waveform was found within 0-10 km of the coastline (69%). Meanwhile, within the distance of 10-50 km and 50-100 km from the coastline, the number of non-Brown waveform was 5% and 3%, respectively. Brown waveform patterns could be found generally starting at 7.58 km from the coastline. Factors such as land near coastal waters, the depth and shape of the surface waters, aerosols in the atmosphere, building (example: lighthouse or ship) found in coastal areas suspected to be the cause of the noise in waveforms. Keywords: Borwn and non-Brown waveform, sea level height, altimetry satellite, identification
MANGROVE COVERAGE CHANGE DETECTION USING LANDSAT IMAGERIES BASED ON HYBRID CLASSIFICATION IN KEMBUNG RIVER, BENGKALIS ISLAND, RIAU PROVINCE Romie Jhonnerie; Vincentius P Siregar; Bisman Nababan; Lilik Budi Prasetyo; Sam Wouthuyzen
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 6 No. 2 (2014): Electronik 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 (905.945 KB) | DOI: 10.29244/jitkt.v6i2.9024

Abstract

ABSTRACT The limited scientific information and lack of attention from stakeholders on the status of mangroves in Kembung River functioned as a basis of this study. Four series of Landsat data recorded in 1996, 2002, 2010, and 2013 were used to map mangrove land cover and changes detection. Hybrid classification technique, a combination of the object-based and random forest classifications, were applied in this study. The result showed that based on hybrid classification, mangrove coverage was detected within 82.6-88.4% overall accuracy. Change detection analyses showed that the mangrove area of Kembung River was relatively stable. For nearly two decades, we found mangrove loss about 197.2 ha, gain of 251.1 ha, and unchanged of 2904.9 ha. Changes in mangrove were generally caused by anthropogenic factors such as mangrove replanting, logging, changes over the function of mangroves into the road, embankment, settlement, shrimp farms, and natural growth. Serious attention from various parties are needed to maintain the existence and sustainablility of mangrove ecosystems in Kembung River.   Keywords: Mangrove, Sungai Kembung, monitoring, Landsat, hybrid classification
CHANGE DETECTION OF CORAL REEF HABITAT USING LANDSAT IMAGERY IN MOROTAI ISLAND NORTH MALUKU PROVINCE Nurhalis Wahiddin; Vincentius P Siregar; Bisman Nababan; Indra Jaya; Sam Wouthuyzen
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 6 No. 2 (2014): Electronik 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 (1214.66 KB) | DOI: 10.29244/jitkt.v6i2.9026

Abstract

ABSTRACT Scientific information on coral reef habitat changes of Morotai island is very limited to none. This study aimed to detect the change of coral reef habitats between 1996 and 2013, using Landsat imagery integrated with field data in 2012. The research was conducted in the coral reef ecosystem of Morotai Island in North Maluku province. Change detection analyses were conducted using supervised classifications and transformation depth invariant index (DII), with five habitat classes i.e., mixed-habitat, coral, seagrass, sand, and rubble. The result showed that in 1996-2002 there was a significant increase in the mix-habitat and rubble classes (11.3% and 32.5%), however,  there  was  a siginifcant decrease in the sand, seagrass, and coral classes of -14.1%, -14.9%, and -16.6%, respectively. In 2002-2013, mixed-habitat, sand, and seagrass classes were increase by 1.1%, 13.3%, and 24.78%, respectively.  Meanwhile, coral and rubble classes were decrease by -22.7% and -27.0%, respectively. Within the period of 1996-2013, there was about 43.6% loss of coral reef of Morotai island.  This was probably caused by the increase of seas surface temperature nad and the increase of human activities in the region. Keywords: coral reef habitats, Landsat, change detection, Morotai Island
DYNAMIC OF SEA LEVEL ANOMALY OF INDONESIAN WATERS Bisman Nababan; Sri Hadianti; Nyoman M.N. Natih
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 | Full PDF (1204.167 KB) | DOI: 10.29244/jitkt.v7i1.9943

Abstract

A trend in sea level rise as a result of global warming could be a threat to small islands and coastal areas in Indonesia. The objective of this study was to determine the trend and variability of mean sea level anomaly (MSLA) in Indonesian waters during the 20 years of observation. The data used in this study were monthly MSLA data obtained from the AVISO website (ftp://ftp.aviso.oceanobs.com). Supporting data were the Southern Oscillation Index (SOI) (http://www.gom.gov.au/climate/enso), Dipole Indian Mode (DIM) index (http://gcmd.nasa.gov/records/GCMD_Indian_Ocean_Dipole.html), and the Pacific Decadal Oscillation (PDO) index (http://research.jisao.washington.edu/pdo/). Eigth stations of Indonesian waters were selected to study the variability of MSLA. In general, MSLA variabilities of Indonesian waters had a seasonal pattern, positively correlated with the SOI index, and negatively correlated with DIM and PDO indexes. The partial correlation of DIM was more dominant in west of Sumatra (r=-0.52) and south of Java (r=-0.44), PDO was more dominant in the northern waters of Papua (r=-0.37) and Makassar Strait (r=-0.33), and SOI was more dominant in northern Papua (r=0.52) and less toward the west of Indonesian waters. Overall, the MSLA variability of Indonesian waters can be explained by the variabilities of SOI, DIM, and PDO indexes with the lowest value in Natuna waters by 12% (R2=0.12) and the highest value in the northern waters of Papua by 54% (R2=0.54). Interannual variabilities were observed during ENSO events (SOI<-10) along with the maximum value of DIM index resulted in the lowest value of MSLA. Meanwhile, the highest value of MSLA was found during La Nina events (SOI>10) in conjunction with a minimum value of DIM and PDO indexes. The average rate of sea level rise in Indonesian waters was 5.84 mm/yr, almost two times higher than the average rate of global sea level rise (3.2 mm/yr). Keywords: mean sea level, anomaly, SOI, DIM, PDO, interannual, ENSO
SEASONAL VARIABILITY OF LIGHT ABSORPTION COEFFICIENT OF SURFACE WATER Bisman Nababan; Denny A. Wiguna; Risti E. Arhatin
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 (1145.421 KB) | DOI: 10.29244/jitkt.v7i2.11121

Abstract

Absorption coefficient measurement can be used in estimating water quality, optical characteristic of water column, and marine bio-optical models. The purposes of this research were to determine values and variability of sea surface absorption coefficient in the northeastern Gulf of Mexico (NEGOM) based on various seasons. The data were collected in spring, summer, and fall seasons in 1999-2000 with AC-9 instrument. The spatial distribution of absorption coefficient showed that relatively high values were generally found along the run off Missisippi, Mobile, Chochawati, Escambia, Apalachicola, and Suwannee rivers, as well as Tampa Bay. Meanwhile, relatively low values were found in offshore region. This pattern followed the distribution pattern of chlorophyll and CDOM. Based on the local region comparison of spectral average value of absorption coefficient, we found a significant difference (α = 95%) among regions with the highest value in the run off of the Mississippi and Mobile rivers, and the lowest value in the offshore region. Comparison of spectral average value of absorption coefficient among seasons at the three primary wavelengths (blue=440 nm, green=510 nm, and red=676 nm) also showed a significant difference (α = 95%) with the highest value during the summer 1999 (Su-99) and the lowest value during the spring of 2000 (Sp-00). Absorption coefficient values were influenced by oceanographic factors that varied in every season such as wind, surface currents, upwelling, the location and speed of the Loop Current, and the river discharge of fresh water into the NEGOM.Keywords: absorption coefficient, seasons, chlorophyll, CDOM, northeastern Gulf of Mexico
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
SEA SURFACE TEMPERATURE DAN CHLOROPHYLL-A CONCENTRATION VARIABILITIES OF JAKARTA BAY AND ITS SURROUNDING WATERS Bisman Nababan
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 | Full PDF (526.795 KB) | DOI: 10.29244/jitkt.v8i1.13915

Abstract

Variability of sea surface temperature (SST) and the concentration of chlorophyll-a (Chla) in Jakarta Bay and its surrounding waters were analyzed based on the time series data of monthly mean SST and Chla estimated by NOAA AVHRR, SeaWiFS, and MODIS satellites for 17 years (1997 to 2014). Generally, the monthly mean SST values fluctuated seasonally with the semi-annual pattern with the maximum value occurred in the second transitional season (Oct-Nov) and relatively high in the first transitional season (Mar). In contrast, the minimum of monthly mean SST values was found during the east season (Jul) and relatively low during the west season (Des-Jan). SST variabilities were generally associated with the sun position, sea water circulation, and rainfall. Based on MODIS data, the minimum-maximum of monthly mean SST ranged of 28.39°C-32.58°C. Seasonal fluctuations with the semi-annual pattern also occurred in the monthly mean Chla values with the maximum value occurred during the west season (Des-Jan) and relatively high values occurred during the east season (Jun). In contrast, the minimum of the monthly mean Chla was found during the second transition season (Sep-Oct) and relatively low during the first transitional season (March-Apr). The minimum-maximum of monthly mean Chla ranged of 0.09 mg/m3-2.50 mg/m3. Chla fluctuations were generally associated with the variabilities of rainfall, river water discharge, and sea water circulation of the Java Sea. Anomalous climatic factors such as El Nino Southern Oscillation (ENSO) and La Nina produced a significant impact on the SST and Chla interannual variability. Generally, the ENSO phenomenon lo-wers the value SST and Chla, while La Nina events tended to increase Chla values.Keywords: sea surface temperature, chlorophyll-a, fluctuation, NOAA AVHRR, SeaWiFS, MODIS
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.
ANALISIS RETRACKING WAVEFORM DATA SATELIT ALTIMETER PADA TELUK, PERAIRAN PULAU-PULAU KECIL, DAN LAUT DALAM DI LAUT HALMAHERA Maya Eria Br Sinurat; Bisman Nababan; Jonson Lumban Gaol
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 11 No. 3 (2019): 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 (579.544 KB) | DOI: 10.29244/jitkt.v11i3.27101

Abstract

Akurasi estimasi tinggi muka laut (SSH) dari satelit altimeter sangat dipengaruhi oleh kondisi perairan dan daratan disekitar perairan tersebut. Estimasi SSH di laut lepas umumnya sudah akurat. Namun, pada daerah pantai, estimasi SSH kurang akurat karena gangguan pantulan sinyal dari daratan. Penelitian ini bertujuan untuk melakukan analisis retracking waveform satelit altimeter pada perairan yang kompleks di Laut Halmahera. Data yang digunakan pada penelitian ini yaitu data waveform dari Sensor Geophysical Data Record type D (SGDR-D) Jason-2 dan Jason-3 tahun 2017. Algoritma retracking yang digunakan yaitu Offset Centre of Gravity (OCOG), Iced, Threshold, dan Improved Threshold. Hasil retracking waveform menunjukkan semua retracker memberikan perbaikan data SSH yang signifikan kecuali OCOG. Retracker yang paling cocok diaplikasikan di Laut Halmahera pada teluk dangkal dan sempit yaitu Threshold 10%, pada teluk dalam dan lebar yaitu Threshold 50%, serta pada perairan dekat pulau pulau kecil yaitu Threshold 10% dan Threshold 20%. Secara umum, Non-Brown waveform lebih banyak ditemukan di perairan teluk dangkal dan sempit (rata-rata=63,49%) dibandingkan dengan teluk dalam dan lebar (rata-rata=11,51%) dan perairan pulau-pulau kecil (rata-rata=9,57%). Namun demikian, tingkat perbaikan data SSH di perairan teluk dangkal dan sempit lebih tinggi dibandingkan dengan teluk dalam dan lebar serta perairan pulau-pulau kecil dan laut dalam. Persentase peningkatan perbaikan data (IMP) tertinggi yaitu 96,71% dengan algoritma Improved Threshold 10% pada Jason-2 pass 164.
COMPARISON OF CHLOROPHYLL CONCENTRATION ESTIMATION USING TWO DIFFERENT ALGORITHMS AND THE EFFECT OF COLORED DISSOLVED ORGANIC MATTER Bisman Nababan
International Journal of Remote Sensing and Earth Sciences (IJReSES) Vol 5,(2008)
Publisher : National Institute of Aeronautics and Space of Indonesia (LAPAN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (641.08 KB) | DOI: 10.30536/j.ijreses.2008.v5.a1232

Abstract

The effect of colored dissolved organic matter (CDOM) on the Sea-viewing Wide Field-of-view Sensor(Sea WiFS) OC4v4 and the MODIS algorithms used to estimate chlorophyll-a was studied using satellite and situ data collated during seasonal cruises in the Northeastern Gulf of Mexico between 1997 and 2000. For chlorophyll-a concentrations 50 mg m, OC4v4 generally overestimated chlorophyll-a concentration by up to 300 percent. The MODIS algorithm provided better estimates of high CDOM concentration, found typically nearshore in noterhn summer and spring. For oceanic waters where chlorophyll-a concentrations 1.0 mg m, both OC4v4 and MODIS algorithm had errors within the Sea WiFS mission specification (35 percent) during fall. The OC4v4 algorithm is more susceptible to artifacts due to CDOM absorption of light at 443 mm. Keywords: chlorophyll-a, Mississippi River Plume, Sea WiFS, upwelling, OC4v4.