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All Journal Ecotrophic, Journal of Environmental Science ILMU KELAUTAN: Indonesian Journal of Marine Sciences Journal of Environment INTERNATIONAL JOURNAL OF ENVIRONMENT AND GEOSCIENCES
Takahiro Osawa
CReSOS Unud
Agriculture, Biological Sciences & Forestry Earth & Planetary Sciences Environmental Science

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Journal : INTERNATIONAL JOURNAL OF ENVIRONMENT AND GEOSCIENCES

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Monitoring Total Suspended Solid Distribution In Coastal Bali Area Using MODIS Satellite Data Ippah, Imro’atul; Osawa, Takahiro; Nuarsa, I Wayan
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.p04

Abstract

Total Suspended Solid (TSS) is one important parameter for water quality. This research aims to analyze MODIS feasibility for identifying TSS, to identify TSS monthly patterns and annual patterns variability, and to analyze the TSS distribution patterns around Bali coastal area. Observation data of the wet season was observed in Benoa Bay on 2nd October 2013 and the dry season was observed in Perancak from July on 28th to July 31st, 2009. The comparison between observation data and satellite data was used to establish a new modification algorithm for suitable conditions around Bali coastal area. Based on research analysis, the feasibility of MODIS was different in each season. In the wet season, the coefficient correlation was (r) = 0.55 and in the dry season, it was (r) = 0.68. poor correlation in the wet season indicated the bottom effect of the area which has a shallow and heterogeneous depth. The TSS average in the wet season was 75.55 mg/l and 55.97 mg/l in the dry season. The highest value was analyzed in November (82.74 mg/l) and the lowest value in June (46.41 mg/l). During wet season, the stream volume and the stream flow rate increase and bring the TSS into coastal areas through the runoff process. The mapping patterns showed that the southern coastal area and western coastal area of Bali had a high value every month. The northern coastal had a high value only in the wet season. The characteristic of Bali river area, which is perennial and intermittent rivers caused this phenomenon. The population and Bali land-use area also affected the high TSS in these areas. Yearly patterns of TSS from 2009 to 2013 around Bali coastal areas were different every year. The highest TSS distribution observed in 2013 wet season is 87.75 mg/l. The lowest TSS distribution occurred in 2009 dry season with a value of 52.2 mg/l. The TSS tends to increase every year due to the changing in Bali land use. TSS patterns from 2009 to 2013 were dynamic every year. The El Nina and La Nino events also gave impact on the patterns. The MODIS feasibility in different locations was different depending on the characteristic of the physical property of water. The shallow and small area causes misinterpretation of the satellite reflectance. The TSS monthly patterns depended on the season and the mapping can be used to describe the sources of TSS pollution, the distribution, and the quantity of TSS in the coastal area.
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 Ayu Margaworo Pamungkas Chonnaniyah, Chonnaniyah Dwi Puspa Arini Feronika, Feronika Gathot Winarso, Gathot I Gede Hendrawan I NYOMAN MERIT I Wayan Arthana I Wayan Gede Astawa Karang I Wayan Nuarsa I Wayan Sandi Adnyana Ippah, Imro’atul Kuncoro Teguh Setiawan, Kuncoro Teguh MASITA DWI MANDINI MANESSA, MASITA DWI MANDINI Novi Susetyo Adi, Novi Susetyo Putu Hadi Wiguna, Pande Rosid, Mohammad Syamsu Suardana, A.A. Md. Ananda Putra Supardjo, Harsono Wati, Kadek Setiya Wikanti Asriningrum, Wikanti