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All Journal Jurnal Ilmu dan Teknologi Kelautan Tropis Indonesian Journal of Geography Journal of Marine and Aquatic Sciences Buletin Udayana Mengabdi Ecotrophic, Journal of Environmental Science REKAYASA INDONESIAN JOURNAL OF APPLIED PHYSICS Jurnal Geografi Jurnal Penelitian Perikanan Indonesia Journal of Marine Research and Technology International Journal of Remote Sensing and Earth Sciences (IJReSES) INTERNATIONAL JOURNAL OF ENVIRONMENT AND GEOSCIENCES International Journal of Environmental, Sustainability, and Social Science The International Journal of Remote Sensing and Earth Sciences (IJReSES)
I Wayan Gede Astawa Karang
Faculty Of Marine Science And Fisheries, Udayana University, Bukit Jimbaran, Bali 80361
Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Computer Science & IT Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Library & Information Science Materials Science & Nanotechnology Physics Social Sciences Other

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Pemetaan Distribusi Lamun di Selat Ceningan Menggunakan Drone Komersial I Gede Andika Wijantara; I Wayan Gede Astawa Karang; Gede Surya Indrawan
Journal of Marine and Aquatic Sciences Vol 8 No 2 (2022)
Publisher : Fakultas Kelautan dan Perikanan Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/jmas.2022.v08.i02.p12

Abstract

Remote sensing is growing with the drone which can overcome problems and weaknesses on satellite imagery. This research uses mapping techniques on seagrass to the species level using drones that use the high resolution to generate data. The purpose of this study was to determine the distribution species of seagrass in Ceningan Strait using drone. Data is collected at the date of 12 and 13 march 2020 by using 50 cm x 50 cm transect which is done by systematic random sampling, and images capture using drones phantom 3 standard by performing five flights, and the results will be combined into one form of a mosaic. The method used is the classification of GEOBIA (Geographic Object Based Image Analysis) which is validated with field data. From the results of the research conducted, three species were identified using drones, namely seagrass with the species Thalasia hemprichi, Cymodocea rotundata, and Syringodium isoetifolium. The results of the drone image classification showed that the variation in the area of cover of each species with the highest incidence was seagrass with Cymodocea rotundata (2.46 ha), followed by Thalasia hemprichi (1.02 ha), and Syringodium isoetifolium (0.26 ha). The results of the image classification show a fairly good level of accuracy with an accuracy value of 68% and the kappa coefficient with a value of 0.55. From the results obtained, it was concluded that the mapping of seagrass species using drones was categorized as quite good.
Estimasi Simpanan Karbon Hutan Mangrove Menggunakan Citra (SAR) Synthetic Aperture Radar Sentinel -1 di Taman Hutan Raya Ngurah Rai,Bali Gede Dicky Pradipta Wedayana; I Wayan Gede Astawa Karang; Abd Rahman As-syakur
Journal of Marine Research and Technology Vol 6 No 1 (2023): FEBRUARI 2023
Publisher : Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2023.v06.i01.p03

Abstract

Taman Hutan Raya (Tahura) Ngurah Rai, Bali, is recorded to have a mangrove forest covering an area of 1,373.5 ha, which plays a role in absorbing carbon from the atmosphere. Carbon is stored in the form of biomass. The bigger the biomass, the bigger the carbon stock in it. Direct measurement of biomass in the field requires an expensive method, a relatively long time, and narrow area coverage. Nowadays, the weakness of measuring carbon stocks directly in the field can be overcome by remote sensing approaches, especially estimations from satellite imagery combined with geographic information systems (SIG). One of the images that can be used to estimate carbon stock is the Sentinel-1 Synthetic Aperture Radar (SAR) image. The aim of this research is to estimate biomass and carbon stocks based on SAR backscatter distribution. The method used is the analysis of satellite imagery combined with field data. Field data collection and above-ground biomass (AGB) calculations were carried out by taking 30 plots with a plot size of 10 x 10 m. The results showed that there was a correlation between the backscatter value of SAR images and AGB from field measurements (r = 0.59 and the AGB estimation model y = 57.42x + 1223.8, where y is biomass and x is backscatter), and the coefficient of determination R2 = 0.36. The estimation model developed next is used to calculate the overall AGB, which is then used to estimate the overall aboveground carbon storage.
Estimasi Simpanan Karbon di Padang Lamun di Perairan Sumberkima Buleleng, Bali Gilang Pratama; I Wayan Gede Astawa Karang; I Nyoman Giri Putra
Journal of Marine Research and Technology Vol 6 No 1 (2023): FEBRUARI 2023
Publisher : Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2023.v06.i01.p04

Abstract

Seagrass is one of the vegetation that has the potential to absorb carbon in Sumberkima waters, Bali. This study aimed to determine the density of seagrass and the estimated value of carbon storage at the top of the substrate (leaves) and at the bottom of the substrate (roots and rhizomes) in Sumberkima waters, Bali. This research was conducted on two islands, namely Pulau Gisik and Pulau Pasir Putih, on September 11 to October 8, 2021, where each island was taken 5 stations with a quadrant transect size of 50cm x 50cm, where each line transect was taken seagrass every 0 m, 50 m, and 100 m. The types of seagrasses found on Pasir Putih Island were Thalassia hemprichii, Cyomodocea serrulata, and C. rotundata while on Gisik Island, the types of seagrasses found were Thalassia hemprichii, Enhalus acoroides, Cymodocea rotundata, C. serrulata, and Halophila ovalis. The density of seagrass on Pasir Putih Island was, on average, between 40 - 87 stands/m2 with the category of rare to somewhat dense, while on Gisik Island, the average is between 35 - 44 stands/m2, indicating a rare category. Estimated total carbon storage in the upper substrate (leaves) on Pasir Putih Island and Gisik Island. The value of carbon storage in Pasir Putih Island at the top of the substrate (leaves) was 0.04 tons/ha, while at the bottom of the substrate (rhizomes and roots) was 0.05 tons/ha, and the value of carbon storage in Gisik Island was at the top. the substrate (leaves) was 0.03 tons/ha, while at the bottom of the substrate (rhizomes and roots), it was 0.04 tons/ha
Perbandingan Akurasi Metode Empiris untuk Pemetaan Batimetri Perairan Benoa, Bali, Menggunakan Citra Satelit SPOT Syifa’ul Qolbiyatun Nisa; I Wayan Gede Astawa Karang; I Dewa Nyoman Nurweda Putra; Kuncoro Teguh Setiawan; Kholifatul Aziz
Journal of Marine Research and Technology Vol 6 No 1 (2023): FEBRUARI 2023
Publisher : Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2023.v06.i01.p09

Abstract

Satellite Derived Bathymetry (SDB) is an alternative method to obtain bathymetry information data developed by utilizing image data as data sources. This study aimed to compare the accuracy of five empiric methods: the Stumpf Method, Polynomial Method, Multilinear Regression Method (MLR), Lyzenga Method, and Van Hengel and Spitzer Methods (VHS). This research was located in Benoa, Denpasar, and Bali using SPOT 6 satellite imagery with a spatial resolution of 6 meters as the data source. The acquisition was on August 12, 2017, in situ data. The accuracy test was carried out by calculating the coefficient of determination (R2) and the RMSE value. The SPOT 6 image requires an image interpretation process, including radiometric correction and atmospheric correction using DOS and land and water masking using the NDWI equation to obtain accuracy test and bathymetric information. Stumpf method has an RMSE of 5.72 meters, R2 of 0.27. The polynomial method has an RMSE of 6.99 meters R2 of 0.01. The Multilinear Regression method has an RMSE of 5.75 meters R2 of 0.34. The Lyzenga method has an RMSE of 7.66 meters R2 of 0.09. The Van Hengel and Spitzer method has an RMSE of 6.97 meters R2 of 0.03. Based on the results of calculations from this study, the Stumpf method has the highest accuracy with an RMSE of 5.72.
Distribusi Pencemaran Sampah Plastik pada Sempadan Sungai di Bali yang Bermuara di Perairan Selat Bali dengan Analisis Generalized Additive Models (GAM) Putu Bagus Angga Utama; I Gede Hendrawan; I Wayan Gede Astawa Karang; Putra Bagus Panji Pamungkas
Journal of Marine Research and Technology Vol 6 No 1 (2023): FEBRUARI 2023
Publisher : Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2023.v06.i01.p10

Abstract

Plastic waste in the oceans is a global problem which becomes a primary concern. The oceans become the final waste shelter that comes from land. Rivers essentially distribute plastic waste from the ground to the sea. Still, few studies currently examine waste distribution on riverbanks, especially rivers that discharge into the Bali Strait. This study aimed to determine the distribution of plastic waste along rivers in Bali Island that discharge into Bali Strait. Waste data was collected using the method developed by CSIRO (Commonwealth Scientific and Industrial Research Organisation). The data collected was used to generate prediction models with GAM to predict the distribution of plastic waste on riverbanks. The GAM method was chosen because it can accommodate non-linear influences; furthermore, GAM uses the smooth function to substitute details of parametric relationships on covariates so that it would give a good prediction. The distribution of plastic waste in 30 rivers was predicted. This research data showed that the most common waste found was a plastic waste at 90%, and non-plastic waste was found at 10%. Based on the prediction, most of the distribution of plastic waste along these 30 rivers had a relative concentration of plastic waste of about 0-20%. The highest concentration of plastic waste was found on the riverbanks of Selanbawak village, Pekutatan village, Pulukan village, Pendem village, and Tuwed village, with 80-100%. The riverbanks close to markets and tourism destinations and the number of populations with a strong relationship with smooth contributions caused relatively high plastic waste concentration. The prediction of the total plastic waste leakage at the riverbanks of the 30 rivers is 3,438,472 pieces, which this plastic waste will pollute Bali Strait.
Konsentrasi Makroplastik Pada Ekosistem Terumbu Karang Di Perairan Pesisir Pemuteran Dan Padang Bai I Putu Trisna Buana Putra; I Gede Hendrawan; I Wayan Gede Astawa Karang
Journal of Marine Research and Technology Vol 6 No 1 (2023): FEBRUARI 2023
Publisher : Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2023.v06.i01.p02

Abstract

Marine debris can be a severe problem in the coastal areas and small islands of Indonesia, which are the habitat of marine organisms and their ecosystems. This is, of course, related to unmanaged waste in various provinces in Indonesia, such as the Bali Province, where as much as 52% of waste in Bali needs to be appropriately managed. Marine debris can be generated from various activities on land and at sea, such as residential areas, industrial activities, offshore activities, and other activities on the island of Bali. The waters of Pemuteran and Padang Bai have coral reef ecosystems. Coral reefs function as a food warehouse for fisheries, a place to live and spawn, and physically coral reefs function as breakwaters and beach protectors. Marine debris can harm coral ecosystems, where it can cause scratches, shards, and disease to corals. This study aimed to analyze macroplastics' characteristics, concentration, and potential relationship to coral reefs. The macro plastic survey used an adaptation of the CSIRO method. The results of this study indicate that the macro plastic characteristics found in the Pemuteran waters were soft plastic types with concentration values ??ranging from 0.02 to 0.03 pieces/m2. In contrast, there were fiber, soft plastic, and hard plastic types with higher concentration values in the Padang Bai waters. Ranged from 0.09 to 0.12 pieces/m2. The ratio of macroplastic to the percentage of live coral cover is 0.98, which means it is inversely proportional; if the amount of macroplastic increases, it will decrease the percentage of live coral cover. The effect of microplastic on the percentage of live coral cover was very significant, with a determination value of 0.96.
Estimating Surface Current from HIMAWARI-8 SST Data using Particle Image Velocimetry Method (Case Study in The Flores Sea) Kadek Setiya Wati; Takahiro Osawa; I Wayan Gede Astawa Karang
INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 13, No 2 (2023): IJAP Volume 13 ISSUE 02 YEAR 2023
Publisher : Department of Physics, Sebelas Maret University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13057/ijap.v13i2.76131

Abstract

Four High-Frequency radar systems (HF) have been installed in Indonesia to monitor surface currents. In-situ ocean current observations are relatively expensive and limited by spatial and temporal resolution. Satellite remote sensing enables the estimate of surface current data generally from surface tracer data, including sea surface temperature (SST). Various methodologies have been developed to obtain surface currents. With Himawari-8 SST data, this study examines the accuracy of the resulting estimation. The cross-correlation fields of two identical-sized interrogation windows obtained from sequential images are employed in Particle Image Velocimetry (PIV). The HF radar in Labuan Bajo was used to validate surface current velocity estimates. RMSE, bias, and the Willmott index determined the accuracy. According to the estimates of surface currents made on July 29, 2022, the results follow a monsoon characteristic wind pattern in the Flores Sea. HF radar observations better validate the V component current estimation than the U component current estimation. A study of sea surface currents from SST data is lacking in Indonesian seas, and more repetition is required. As a result, This method has the potential can be employed to observe aquatic environments in other Indonesian areas.
Studi Perubahan Garis Pantai di Teluk Penyu, Cilacap, Jawa Tengah Menggunakan Citra Sentinel-1 dan Sentinel-2 Azhar Muhammad Hanisa; Abd. Rahman As-syakur; I Wayan Gede Astawa Karang
Journal of Marine Research and Technology Vol 7 No 1 (2024): FEBRUARI 2024
Publisher : Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2024.v07.i01.p02

Abstract

The coastline is defined as the location where water and land contact at any given time. Coastline change is considered as one of the most dynamic processes in coastal areas and is an indication of coastal accretion and erosion. The process of accretion and erosion can cause beach conditions to become unbalanced and even damaged. Cilacap Regency has a coastline of approximately 80 km which is directly adjacent to the Indian Ocean. The coast of Cilacap experienced changes in coastline which tended to be high from 1999-2008. For this reason, research has been carried out regarding coastline changes in Penyu Bay using remote sensing. The data used are Sentinel-1 and Sentinel-2 satellite images for 2016 and 2021. The analysis of shoreline changes uses the Digital Shoreline Analysis System (DSAS). The results of an analysis of shoreline changes in Penyu Bay from 2016 to 2021 show an average accretion of 1,278.49 m2 at Sentinel-1. While Sentinel-2 shows an average accretion of 2,917.68 m2. The average rate of line change per year on Sentinel-1 is 1 m/year with an indication of accretion and Sentinel-2 is 1,11 m/year with an indication of erosion. Accuracy test with Root Mean Square Error shows that Sentinel-1 is 36.80 m and Sentinel-2 is 15.43 m. Sentinel-1 has an accuracy value (CE90) of 55.84 m in class 2 with a scale of 1:100,000, while Sentinel-2 is 23.41 m in class 2 with a scale of 1:50,000.
Analisis Status Mutu Air Laut Berdasarkan Metode STORET di Pelabuhan Gilimanuk Bali Valenthio Sidauruk; I Wayan Gede Astawa Karang; I Dewa Nyoman Nurweda Putra
Journal of Marine Research and Technology Vol 7 No 1 (2024): FEBRUARI 2024
Publisher : Department of Marine Sciences, Faculty of Marine and Fisheries, Universitas Udayana

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JMRT.2024.v07.i01.p09

Abstract

The harbor area has a high risk of pollution. Anthropogenic activities such as ship operations, ship traffic and material used by ships will trigger a decrease in water quality and have a negative impact to the water in harbor area. This study aimed to determined the content of parameters and water quality status at Gilimanuk Harbor, Bali. Samples were taken during the transitional of Summer and Rainy season (September-November 2022) three times with a one-month interval. The parameters used in this study were: temperature, Total Suspenden\d Solid (TSS), pH, salinity, ammonia, lead and coliform. The additional parameters in this study are rainfall, wind and currents to determine the relationship between data. Water quality status in this study was analysed by STORET method, with the water quality standard referenced The Government Regulation Number 22 of 2022 for harbor waters. The parameters that exceeded the water quality standard in this study were Ammonia and the water quality status for the port waters based on the STORET method, specifically at a distance of 50 meters and 500 meters from the shore is class A with (Not Polluted) category while at a distance of 1000 meters from the shore is class B (Lightly Polluted) category. With these results, it can be seen that rainfall, wind and currents have an impact on the distribution of pollutants in the sea water.
Internal solitary waves observation and feature extraction based on wavelet transform by Sentinel-1A in Lombok Strait, Indonesia Chonnaniyah, Chonnaniyah; Osawa, Takahiro; Karang, I Wayan Gede Astawa
International Journal of Environment and Geosciences Vol 5 No 1 (2024): International Journal of Environment and Geosciences
Publisher : Graduate Study of Environmental Sciences, Postgraduate Program of Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/ijeg.2024.v05.i01.p05

Abstract

Lombok Strait is an essential pathway in trans-oceanic water mass transport. Due to this water mass transport flowing over Indonesian waters, the current is known as Indonesian Throughflow (ITF), which plays a role in the transfer of warm water masses from the Pacific to the Indian Ocean annually. Lombok Strait has intensive characteristics of the internal waves (IWs) generation because of the strong current that passes through the complex bathymetry along the strait area. IWs with large amplitude and nonlinear properties are known as Internal Solitary Waves (ISW) that can be detected by Synthetic Aperture Radar (SAR) images. A Wavelet Transform method for ISW feature extraction was applied to SAR images by Sentinel-1A (C-band). ISW packet characteristics can be distinguished from other phenomena based on their geometrical structure and shape. ISW packet pattern consists of light and dark lines which decrease intensity from front to rear. SAR observation detected 5 parameters (phase speed, soliton numbers, wavelength, first crest length, and propagation direction). The arc-like ISW in the Lombok Strait propagated to the North of the sill with average phase speeds of about 2.13 m/s and was frequently detected during the northwest monsoon (NWM). The detected soliton number is less than 6 solitons per packet with a wavelength of about 1 – 4 km, and the first crest length varies from about 12.16 km to more than 100 km. ISW detected in Sentinel-1A images were located at the bathymetry about 800 meters around the Lombok Strait area.
Co-Authors Abd. Rahman As-syakur Alexis Chappuis Anak Agung Istri Candra Kirana Anisa Dea Novianti Artha C. Rosevina Anak Ampun Astaman, I Dewa Made Khrisna Putra Astiti Ratnasari Astiti Ratnasari Azhar Muhammad Hanisa Brasika, Ida Bagus Mandhara Chonnaniyah Chonnaniyah Chonnaniyah, Chonnaniyah Cindi Ayu Lestari Cornelia Coraima Lazaren Dian Novianto Dwi Budi Wiyanto Dwi Nindra Saputra Eka Andiani, Anak Agung Elok Faiqoh Elvita Rahmani Fitra Cahya Prima Fumihiko Nishio Gede Dicky Pradipta Wedayana Gede Indra Putra Pratama Gede Surya Indrawan Gilang Pratama I Dewa Ayu Ratna Raksa Eka Putri I Dewa Nym. Nurweda P., I Gede Andika Wijantara I Gede Hendrawan I Gede Merta Yoga Pratama I Gede Mita Anjas Swara I Gusti Agung Bagus Wisesa Sastra I Gusti Agung Indah Mahasani I Gusti Bagus Sila Dharma I Gusti Bagus Sila Dharma I Kadek Dedy Antara Putra I Ketut Suta Negara I Made Ekayana I Nengah Jaya Nugraha I Nyoman Januarta Triska Putra I Putu Trisna Buana Putra I Wayan Arthana I Wayan Eka Dharmawan I Wayan Krisna Eka Putra I Wayan Krisna Eka Putra I Wayan Matsya Deva Nagendra I Wayan Matsya Deva Nagendra I Wayan Nuarsa I Wayan Nurjaya IDA AYU ASTARINI IPG Eka Handrayana Putra Irwan Jatmiko Jero Ketut Tri Ayu Lestari Kadek Bagus Padmaningrat Kadek Dwi Artama Kadek Setiya Wati Kholifatul Aziz Kuncoro Teguh Setiawan Kuncoro Teguh Setiawan Luh Made Chandra Luh Made Chandra Luh Putu Ayu Depi Nurcahyani Made Narayana Adibhusana Made Ryan Dwiputra Made Suartana Naila Makfiya Ni Kadek Martini Ni Luh Kade Paramita Kusuma Ni Luh Putu Ayu Sumarni Ni Luh Putu Ratih Pravitha Ni Luh Putu Ria Puspitha Ni Putu Eva Damayanti Nidzar Muhammad Rafly Nikmah Fitria Nuraini Nuryani Widagti Pande Ketut Cahya Krisnanta Arioka Putra Bagus Panji Pamungkas Putra, I Nyoman Giri Putu Bagus Angga Utama Putu Eka Tulistiawan Rony Clinton Sabil Al Alif Siti Rohani Syifa’ul Qolbiyatun Nisa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Takahiro Osawa Tulistiawan, Putu Eka Valenthio Sidauruk Wati, Kadek Setiya Widiastuti Karim Widiastuti Karim Widiastuti Widiastuti Widiastuti Widiastuti Yasa, Putu Kumara YASUHIRO SUGIMORI Yasuhiro Sugimori Yoga Ibnu Graha Yuli Naulita Yulianto Suteja