Articles

Landsat 8 Observation of the Internal Solitary Waves in the Lombok Strait Karang, I Wayan Gede Astawa; Chonnaniyah, Chonnaniyah; Osawa, Takahiro
Indonesian Journal of Geography Vol 51, No 3 (2019): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (182.143 KB) | DOI: 10.22146/ijg.42655

Abstract

Landsat  8,  Landsat  Data  Continuity  Mission  (LDCM)  satellite,  was  launched  on  11 February 2013 with Operation Land Imager (OLI) sensors. Tis sensor has better radiometric performance than the previous mission, which is quantized in the 12-bit dynamic range due to an increase in the signal-to-noise (SNR) ratio. In this analysis, the spatio-temporal distribution of the propagation of the internal solitary wave (ISW) in the Lombok Strait was extracted from the Landsat 8 images described for the first time.  Tere were 14 ISW events studied for period 2014  -  2015  using  Landsat  8.  Te  manifestations  of  ISW  recorded  on  Landsat  8  images  were then extracted using digitization method to investigate and measure several parameters and ISW distribution in the Lombok Strait. Te estimation results of the average ISW phase velocity in this study are 2.05 ms-1 with the direction of propagation heading north at an average angle of 19.08°. Tis study has shown that Landsat 8 can be used to monitor and analyze several internal wave parameters in the ocean.
STUDY OF TOTAL SUSPENDED MATTER DISTRIBUTION USING SATELLITE DATA AND NUMERICAL SIMULATION IN PORONG SIDOARJO, EAST JAVA -, Herman; Osawa, Takahiro; Arthana, I W
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 5 No 1
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

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Abstract

Sedimentation is one of coastal dynamic processes. Sedimentation in the mud volcano of Porong at Sidoarjo is an important phenomena to be known as a reference to find out a good solution in the tragedy of mud volcano eruption. Observation of the sedimentation process in the mud volcano eruption of Porong Sidoarjo needs in situ data and data processing technique to know of more details about sedimentation process and the main cause of the sedimentation and the large mud volcano eruption. Therefore, studying of sedimentation process needs the quick timing and high accuracy method. One of the technique which can be used is remote sensing method compared with numerical model and in situ data oservation. Study area is in the Regency of Porong Sidoarjo Province of East Java on August 2008 in position of 7°30’ S - 7°40’ S and 112° 30’ E - 113°30’ E. The aim of this study is to know the pattern of TSM distribution from satellite image using the algorithm which was introduced by Zhou and Kutser. The pattern of TSM from the Landsat and Modis satellite images show that the TSM distribution from the porong river, will then accumulate to the estuary. But, the concentration will decrease in the area that is far from the estuary. This is caused by the influence of the tide current in the Madura strait.From the simulation model was shown that the sediment distribution is influenced by pattern of current generated by tide. High tide where the current move to the upstream sediment in the porong estuary, the sediment was then accumulated in the estuary area. However, at low tide where the current move to the downstream, sediment transportation will move out from the estuary at the maximum level. The pattern of current shows that the moving is to the south direction in the porong coastal that will cause the sediment concentration that out from the porong estuary willgo to to the south direction. The water flow in front of the mouth of porong estuary maybe one of the cause why the sediment distribution tend to move to the south direction.
EVALUATION OF LAND USE WITH REGIONAL SPATIAL PLAN (RTRW) USING SATELLITE DATA AND GIS IN BATUR UNESCO GLOBAL GEOPARK Utama, Putu Wira; Osawa, Takahiro; Sandi Adnyana, I Wayan
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 12 No 1 (2018)
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (594.771 KB) | DOI: 10.24843/EJES.2018.v12.i01.p08

Abstract

Development in ??Batur UNESCO Global Geopark which has an area of ??19,422.39 ha has increased significantly in recent years. The existence of limited land and to know the suitability of land use, it is necessary to evaluate of land use with regional spatial plan (RTRW). Landsat 8 satellite remote sensing data on 27 September 2017 is used to create land use maps. Land use maps obtained through the process of image classification using supervised classification method and verified by ground check. From this technique result 11 classes of land use. Furthermore, to evaluate of land use suitability was conducted by comparing land use with regional spatial plan (RTRW). In this process, there is an overlay between the land use maps with regional spatial plan (RTRW) map using geographic information system (GIS). The results of evaluation land use in Batur UNESCO Global Geopark with regional spatial plan (RTRW) overall has suitable area 10,863.14 ha (55.93%), not suitable area 8,275.58 ha (42.61%) and not detected/cloud interference 283.67 ha (1.46%).
EVALUATION OF TUNA FISHING GROUND IN SOUTHERN COAST OF JAVA - SUMBAWA SEA USING SATELLITE OBSERVED DATA SATIBI, MOKHLAS; OSAWA, TAKAHIRO; ARTHANA, I WAYAN
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 4 No 1
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

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Abstract

Potential fishery in territorial water of South Java - Sumbawa Sea has not been exploited maximally. Tuna is one of fisherypotency in the territorial water of South Java - Sumbawa. Tuna is the important economic value because it represent one ofexporting commodity enthused by overseas consumer.Research was conducted in the Southern Java – Sumbawa, Indian Ocean 90 S - 160 S; 1060 E - 1210 E, using fish catch data2003 – 2006. Research location is in the inclusive Region of Fishery Management IX (DKP and PKSPL, 2003). Data weretaken from a daily fish catch of PT. Perikanan Samudra Besar (PSB) Benoa Bali 2003 - 2006.Sea level anomaly (SLA) data were estimated from Altimetry satellite (Jason 1), wind speed data was from Scatterometersatellite and sea surface temperature (SST) data was from Microwave satellite.Based on the result of this research, sea level anomaly of southern coast of Java-Sumbawa was fluctuated according tomonsoon. The highest bigeye tuna fish catched was 40 tuna in June 2003 and the lowest bigeye tuna fish was 2 tuna inNovember 2005. Maximum SLA observe during southeast monsoon was 21.77 cm in august 2005, while minimum SLAobserved during southeast monsoon was -18.15 cm in October 2003. Sea surface temperature of southern coast of Java-Sumbawa also fluctuated according to monsoon. Maximum SST observed during northwest monsoon was 30.450 C in March2006, while minimum SST observed during southeast monsoon was 25.050 C in August 2006. The highest wind speed was10.20 m/sec in June 2004 and the lowest was 2.00 m/sec in October 2004. Wind direction was reversely changed according tomonsoon. Northwest wind monsoon flew eastward and southeast wind monsoon flew westward.Fish production in PT PSB had been done over 4 years since 2003, in northwest and southwest monsoon in constant areaand correlation of linier regression among estimate of fish catching using SLA, SST and wind speed had no correlation. Withfish production during southwest monsoon PT PSB set in SLA negative in different temperature of 30 C, wind speed of 2.00m/sec and with abundant of fish catched. Meanwhile in northeast monsoon that was in positive SLA the fish catching was inlow number.
ESTIMATION OF PRIMARY PRODUCTIVITY FOR TUNA IN INDIAN OCEAN Kasma, Ende; Osawa, Takahiro; Sandi Adnyana, I Wayan
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 4 No 2
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

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Abstract

Indonesia has abundant fisheries potency, one of fisheries potency in Indian Ocean is tuna fish. Primary productivity data used as indicator of tuna fisheries potency in Idian Ocean.Research location is in Indian Ocean 070 - 210 S and 1070 - 1210 E. Weekly satellite data in 2007 used are chlorophyl, sea surface temperature, Photosynthetic Available Radiation (PAR) and euphotic zone (Zeu) data. Daily fisheries data is from tuna fish catching data 2007 in PT. Perikanan Samudera Besar (PT. PSB). Satellite data is processed by Vertically Generalized Production Model (VGPM) formula to obtained primary productivity. Tuna fish catching data correlated to satellite data to know correlation of primary productivity value to fish catching data.Result of this research is there four species of tuna fish catch in Indian Ocean, that are Madidihang or Yellowfin tuna (Thunnus albacores), Bigeye tuna (Thunnus obesus), Southtern Bluefin tuna (Thunnus macoyii), and Albacore (Thunnus alalunga). Where 73% tuna fish is Bigeye tuna. Bigeye, Albacore and Yellowfin tuna are produced annually, while Southern Bluefin tuna in northwest monsoon is no fish production. Chlorophyll-a, sea surface temperature and primary productivity value in research location are from 0,06 mg/m3 to 0,38 mg/m3, from 24,640C to 31,820C, and from 73,22mgC/m2 to 658,57 mgC/m2 respectively. Coefficient correlation in primary productivity and fish catching in fishing ground area is small (r = 0.008), its explained that, fish catching number is not influenced by primary productivity. In high or low primary productivity condition tuna fish catched in Indian Ocean area. Potential fishing ground area of Bigeye tuna, Albacore, Yellowfin and Southern Bluefin tuna in Indian Ocean are in 110 – 160 S and 1060 – 1210 E, the primary productivity value is from 73 mgC/m2day to 732 mgC/m2day and differences of sea surface temperature value of tuna fish are from 240 C to 310 C, 240 C to 300 C, and 250 C to 310 C for Bigeye tuna, Albacore and Yellowfin tuna, respectively. While Southern Bluefin tuna distribution is in temperature area from 260 C to 300 C and primary productivity value is from 92 mgC/m2day to 449 mgC/m2day
STUDY OF ESTIMATE CONCENTRATION OF WATER CONSTITUENTS AT BADUNG STRAIT BALI USING INVERSE MODEL Swardika, I Ketut; Osawa, Takahiro; Arthana, I Wayan
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 1 No 2
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

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Abstract

An algorithm was employed to retrieve the concentrations of three water constituents, chlorophyll-a,suspended matter and colored dissolved organic matter (CDOM) from MODIS (Moderate-ResolutionImaging Spectrometer) in wide range covering from oligotrophic case-1 to turbid case-2 waters at theBadung Strait Bali. The algorithm is a neural network (NN) which is used to parameterize the inverse of aradiative transfer model. It’s used in this study as a multiple nonlinear regression technique. The NN is a feedforward back propagation model with two hidden layers. The NN was trained with computed radiancecovering the range of chlorophyll-a from 0.001 to 64.0 ?g/l, inorganic suspended matter from 0.01 to 50.0mg/l, and CDOM absorption at 440nm from 0.001 to 5.0 m-1. Inputs to the NN are the radiance of the fivespectral channels which were under discussion for MODIS. The outputs are the three water constituentconcentrations. The NN algorithm was tested using in-situ data set on May, September, November 2005 atthe Badung Strait Bali and the north sea of Sumbawa Island and applied to MODIS. The coefficient ofdetermination (R2) between chlorophyll-a concentrations derived from simulation and in-situ data is 0.327,for suspended matter R2 is 0.408. No in-situ measurements of CDOM available for validation. Also, in-situdata were compared with the corresponding distribution obtained by the NASA standard OC4 (OC3M) forMODIS chlorophyll-a algorithm and giving R2 0.188. This study gives better accuracy compare withstandard algorithm. How ever both studies are giving over estimate chlorophyll-a concentration. Since thereare no standard MODIS products available for suspended matter and CDOM, the result of the retrieval by theNN for these two variables could only be assessed by a general knowledge of their concentrations anddistribution patterns
LAND SUBSIDENCE IN SEMARANG A.S., SUPRABADEVI; Osawa, Takahiro; Merit, I Nyoman
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 7 No 2 (2012)
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

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This research aims to identify monitoring land subsidence in Semarang has been done using raster data operation of the DEM in GIS environment. Digital representation of relief of Semarang area was generated from a point map which contains elevation data. The last update of the elevation data was made using geodetic, using Global Positioning System (GPS). Decrease in land distribution is estimated from the data of GPS Geodetic years 2008-2011, in the Semarang area north, west, central, east and south. Reduction in the range of 2008-2009 reached -12.4 cm, then increased in 2009-2010 to be -20-4 cm and -10.5 cm fell back to the years 2010-2011. Decline in the face of the land in Hyderabad occurs mainly in the n01th, east, central and south of Semarang. Subsidence causing damage to infrastmcture, buildings, and results in moving tidal lowlands.damage potential economic loss is cracks in buildings and infrastmcture (roads and bridges), the number of homes that have been tilted and nearly drowned. In addition to direct losses, reduction in ground level also cause indirect losses that rob the increasingly widespread flooding in the northern region of Semarang.in 2008- 2010 June-July with a high tide occurs o.6 cm from the surface of the sea water in the area of Semarang.
OIL SPILL DETECTION USING MODIS DATA (CASE STUDY: OIL POLLUTION AT TIMOR SEA) PUTRA, A.A. GEDE; Osawa, Takahiro; Mahendra, M.S.
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 6 No 2 (2011)
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

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Abstract

On August 21, 2009 an offshore oil rigs located in Block West Australia territorial was exploded. About 500.000 liters/day of crude oil was spill out to the Timar Sea. To detect the oil spreading, this study used MODIS satellite data from 21 August 2009 until 15 March 2011. Besides that, data of wind speed and wind direction, coordinate of pollutant point sources, and Exclusive Economic Zone (EEZ) line are also used to know the covering area of the oil was entered into Indonesian territorial. The oil was classified by visual interpretation methods, these are: dark spot detection, feature extraction and classification. As the result, oil spill covered area increased since August to September 2009. Oil spill on the sea surface then decreased drastically until November 2009. This was due to dispersant spraying which made the oil settled down. But, when a tropical cyclone occurred in December 2009 and January 2010, the settled oil appear again in sea surface but it spread out in various location. This study shows that MODIS data can be used to monitor spreading of oil spill since no cloud cover. The maximum oil covered area was occurred on 24 September 2009 about 7,996-40 km2
CORAL REEF CONDITION DETECTED IN MENJANGAN AND NUSA PENIDA ISLAND USING ALOS/AVNIR-2 SATELLITE DATA UTARI DEWI, IDA AYU; Osawa, Takahiro; Arthana, I Wayan
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 6 No 1 (2011)
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

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Abstract

Wisata terumbu karang sangat diminati oleh wisatawan dalam negeri maupun manca negara. Pulau Menjan­ gan dan Nusa Penida merupakan salah satu lokasi wisata yang yang sangat diminati karena memiliki ekosistem pesisir seperti terumbu karang, hutan bakau, rumput laut dan lain-lain memiliki kekayaan yang beranekaragam. Dalam penelitian ini, data satelit ALOS (AVNIR-2) yang memiliki 3 spektrum tampak yang digunakan untuk mendeteksi daerah penyebarannya. Tujuan  penelitian  ini adalah:  1) Untuk  mengetahui  sebaran terumbu  karang secara umum  di Pulau Men­ jangan dan Pulau Nusa Penida dan 2) Untuk mengetahui perubahan terumbu karang di Pulau Menjangan dan  Pulau Nusa Penida. Akurasi yang baik  (Nusa Penida  81,213%  (2007), 80,334%  (2009), Menjangan  85,555%  (2007), 84,285% (2009)) diperkirakan karena sebagian besar daerah pelatihan sesuai dengan data lapangan. Akurasi dari citra satelit tanpa metode Lyzenga di Nusa Penida Island itu lebih rendah dari keakuratan citra satelit di Pulau Men­ jangan. Hal ini disebabkan oleh 3 faktor-faktor seperti kesalahan klasifi.kasi sesuai dengan interaksi kompleks dari tata ruang topografi, informasi kesalahan definisi dari kelas spektral dan  kesalahan pada citra satelit itu sendiri. Hasil persebaran Pulau Menjangan menunjukkan luasan tutupan terumbu karang 49,04 hektar pada tahun 2009 dan 51,06 hektar pada tahun 2007 dengan perubahan luas terumbu karang meliputi 2102 hektar tingkat persentase 3,95%. Nusa Penida menunjukkan luasan tutupan terumbu karang 399 66 hektar pada tahun 2009 dan  339,65 hektar pada tahun 2007 dan , perubahan cakupan terumbu karang 60.01 hektar tingkat presentase 17,6%. Penurunan terumbu karang di pulau menjangan terjadi karena seperti suhu, serangan predator, gelom­ bang besar dan aktivitas manusia. Terutama pada suhu tinggi yaitu 30° pada Nopember 2001, Desember 20021 Desember 2006, Desember 2007, November 2008, April 2009, April 2010 dan  Desember 2010 Suhu yang tinggi tampaknya memberikan kerusakan besar terhadap terumbu karang sehingga terjadi pemutihan terumbu karang. Peningkatan terumbu karang di nusa penida karena dipengaruhi oleh suhu perairan di Nusa Penida yang optimal  bagi pertumbuhan karang.
AN APPLICATION OF SEGNET FOR DETECTING LANDSLIDE AREAS BY USING FULLY POLARIMETRIC SAR DATA Antara, I Made Oka Guna; Shimizu, Norikazu; Osawa, Takahiro; Nuarsa, I Wayan
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 13 No 2 (2019)
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (793.053 KB) | DOI: 10.24843/EJES.2019.v13.i02.p09

Abstract

The study location of landslide is in Hokkaido, Japan which occurred due to the Iburi Earthquake 2018. In this study the landslide has been estimated by the fully Polarimetric SAR (Pol-SAR) technique based on ALOS-2 PALSAR-2 data using the Yamaguchi’s decomposition. The Yamaguchi's decomposition is proposed by Yoshio Yamaguchi et.al. The data has been analyzed using the deep learning process with SegNet architecture with color composite. In this research, the performance of SegNet is fast and efficient in memory usage. However, the result is not good, based on the Intersection over Union (IoU) evaluation obtained the lowest value is 0.0515 and the highest value is 0.1483. That is because of difficulty to make training datasets and of a small number of datasets. The greater difference between accuracy and loss graph along with higher epochs represents overfitting. The overfitting can be caused by the limited amount of training data and failure of the network to generalize the feature set over the training images.
Co-Authors A. Rahman As-syakur A.A. GEDE PUTRA, A.A. GEDE Abd. Rahman As-syakur Agustin, Dewa Ayu Mery An, Ngo The ANAK AGUNG AYU PUTRININGSIH, ANAK AGUNG AYU Antara, I Made Oka Guna Ardhana, Putu Gede Artabudi, I Nyoman Astiti, Sagung Putri Chandra Ayu Margaworo Pamungkas Budiman, Mohan CHAO FANG ZHAO, CHAO Chonnaniyah, Chonnaniyah Dian Novianto Ende Kasma Fahlevi, Arief Reza Fumihiko Nishio, Fumihiko Herman - I Dewa Nym. Nurweda P., I Dewa Nyoman Nurweda Putra, I Dewa Nyoman Nurweda I Ketut Swardika I NYOMAN MERIT I Putu Gede Ardhana I W Arthana I Wayan Arthana I Wayan Budiarsa Suyasa I Wayan Gede Astawa Karang, I Wayan Gede I Wayan Gede Astawa Karang, I Wayan Gede Astawa I Wayan Kasa I Wayan Nuarsa I Wayan Redi Aryanta I Wayan Redi Aryanta, I Wayan Redi I Wayan Sandi Adnyana I Wayan Sandi Adnyana I. Wayan Nuarsa, I. Wayan IDA AYU UTARI DEWI, IDA AYU IGAG SWANDANA, IGAG IRMA YULIA MADJID, IRMA YULIA KADEK ARY ANGGRAENI, KADEK ARY KADEK ARY ANGGRENI, KADEK ARY Kuncoro Teguh Setiawan, Kuncoro Teguh Lan, Nguyen Tuyet Luh Made Chandra Astiti R. Luh Made Suriwati M.S. Mahendra Made Sudiana Mahendra MASITA DWI MANDINI MANESSA, MASITA DWI MANDINI MOKHLAS SATIBI Molidena, Elis Naningsi, Nuranita NAOTO EBUCHI, NAOTO NAOYA SUZUKI, NAOYA Ni Wayan Ekayanti Ogawara, Kakuji Pandawana, I Dewa Gede Agung Parwata, I Nyoman Sudi Putra, I Kadek Adiana R. PRASETIA, R. SATRIA WAHYU 0ETOM0, SATRIA WAHYU Setiyoko, Agit Shimizu, Norikazu SUPRABADEVI A.S., SUPRABADEVI Suprapto, Nyoman Arto Syifa Wismayati Adawiah, Syifa Wismayati TAKASHI MORIYAMA, TAKASHI Tasuku Tanaka, Tasuku Utama, Putu Wira Ximenes, Romaldo Da Costa Yastika, Putu Edi Yasuhiro Sugimori, Yasuhiro