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RETRIEVAL OF SURFACE CURRENT FROM HIMAWARI-8 SEA SURFACE TEMPERATURE DATA AND PARTICLE IMAGE VELOCIMETRY METHOD Wati, Kadek Setiya; Osawa, Takahiro; Astawa Karang, I Wayan Gede
ECOTROPHIC : Jurnal Ilmu Lingkungan (Journal of Environmental Science) Vol 17 No 2 (2023)
Publisher : Master Program of Environmental Science, Postgraduate Program of Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/EJES.2023.v17.i02.p08

Abstract

As human activity occurs at the surface, which is influenced by surface currents, understanding surface currents is crucial. Ocean currents are not solely caused by wind, but also of other factors, such as sea surface temperature. To obtain surface current data, BMKG used HF radar installed in several places, including Flores Sea. This location is significant because it has large ports and heavy crossing traffic. This study aims to analyse surface current data retrieve from Himawari-8 SST data by applied PIV algorithm. Using the PIV algorithm, a cross-correlation plane is generated by comparing two identically sized interrogation windows obtained from successive images. On 5 December 2022 in the Flores Sea, Himawari-8 SST data was employed to estimate sea surface currents every 10 minutes. Surface current motion varies widely from image to image. Western areas are dominated by westward currents, while central and eastern areas are dominated by eastward currents during daylight hours, and westward currents during the night. Synoptic wind affects surface current movement during those hours. Validation with observational data from the Labuan Bajo HF radar shows that the V component current estimation is better than the U component current estimation. This is particularly prevalent in the south and in areas close to the KAWA radar HF location. Keywords: Flores Sea; SST; Himawari-8; PIV; surface current
PENGENALAN PEMANFAATAN TEKNOLOGI PENGINDERAAN JAUH UNTUK IDENTIFIKASI EKOSISTEM PERAIRAN PESISIR Gede Astawa Karang, I Wayan; Brasika, Ida Bagus Mandhara; Hendrawan, I Gede; Putra, I Dewa Nyoman Nurweda; Yasa, Putu Kumara
Buletin Udayana Mengabdi Vol 23 No 5 (2024): Buletin Udayana Mengabdi
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Teknologi penginderaan jauh telah memasuki berbagai sector dalam analisis potensi dan perubahan lingkungan secara spasial.. Penggunaan data spasial dalam analisis lingkungan menjadi esensial, mendorong perlunya kesadaran masyarakat akan peran teknologi dalam pengelolaan lingkungan khususnya lingkungan pesisir dan laut. Berkenaan hal tersebut, penting untuk mengadopsi pendekatan edukatif guna memperkenalkan konsep ini kepada masyarakat, khsususnya pengenalan sejak dini kepada siswa-siswa sekolah menengah yang sudah mengenal teori maupun praktikum pembelajaran lingkungan dan ekosistem. Pengabdian ini bertujuan untuk mentransfer pengetahuan dari perguruan tinggi kepada masyarakat dengan fokus pada pendidikan dini mengenai teknologi penginderaan jauh. Tujuannya adalah untuk memberikan wawasan tentang teknologi ini serta melatih keterampilan siswa dalam memanfaatkan data penginderaan jauh untuk mengidentifikasi ekosistem wilayah pesisir. Pendekatan yang digunakan dalam pelatihan ini mencakup memberikan penyampaian materi melalui ceramah dan praktik langsung kepada siswa. Kegiatan ini dilaksanakan di SMP Negeri 2 Kuta dan SMP Negeri 3 Kuta Selatan. Pelatihan tentang pemanfaatan teknologi penginderaan jauh untuk identifikasi ekosistem pesisir sangat efektif bagi siswa sekolah menengah. Ini membantu memperluas pengetahuan peserta mengenai perkembangan teknologi masa kini. Hasil evaluasi pelatihan menunjukkan bahwa peserta pelatihan berhasil meningkatkan pengetahuan tentang teknologi penginderaan jauh dan ekosistem pesisir. Dengan demikian, pendekatan edukatif ini memiliki potensi besar dalam meningkatkan pemahaman siswa tentang peran teknologi penginderaan jauh dalam pengolahan lingkungan pesisir, serta mendorong partisipasi mereka dalam upaya pelesatarian ekosistem tersebut.
Validation of Satellite Rainfall Product (GPM-IMERG) an Bali and Nusa Tenggara: A Comparison of Normal Seasons, El Nino and La Nina Events Putu Eka Tulistiawan; I Wayan Gede Astawa Karang; Takahiro Osawa
JURNAL GEOGRAFI Vol 15, No 2 (2023): JURNAL GEOGRAFI
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/jg.v15i2.44967

Abstract

Bali and Nusa Tenggara are regions where monsoonal wind changes and strange interactions between the ocean and atmosphere influence rainfall. The purpose of this research is to evaluate Integrated Multi-Satellite Retrievals for GPM (IMERG) rainfall data using in-situ observations from Bali and Nusa Tenggara, Indonesia, while considering seasonal variations and the El Nino-Southern Oscillation (ENSO) phenomenon. The study combines rainfall data from synoptic stations with rain gauge measurements over ten years, from January 2012 to December 2021, to obtain more accurate verification results. The study's findings indicate that, apart from the transitional seasons, IMERG data provides substantial estimates of monthly rainfall accumulation with low error values for both light and heavy rainfall. The study also reveals that the islands' complexity and topography can impact each province's validation values. The verification results show excellent accuracy in flat terrain areas and moderate elevations, while performance decreases in regions with high altitudes. These findings are significant because IMERG data can estimate rainfall for regions lacking monitoring stations during specific seasons and active ENSO conditions. Thus, this information can serve as a valuable tool to address the issue of data unavailability in hard-to-access areas and contribute to optimizing water resource management and weather-related disaster mitigation. Keywords: Validation, Rainfall, IMERG, ENSO
Analysis of Potential Natural Disaster Risks in Buleleng Regency PUTRA, I Wayan Krisna Eka; DHARMA, I Gusti Bagus Sila; ASTARINI, Ida Ayu; KARANG, I Wayan Gede Astawa
International Journal of Environmental, Sustainability, and Social Science Vol. 4 No. 6 (2023): International Journal of Environmental, Sustainability, and Social Science (Nov
Publisher : PT Keberlanjutan Strategis Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.38142/ijesss.v4i6.925

Abstract

Buleleng is one of the regency in the Province of Bali which has various potential disaster risks, mainly dominated by natural disaster. This condition is influenced by the topography of the Buleleng Regency area which has the characteristics of Nyegara Gunung, namely to the north is a coastal area while to the south is a hill’s area. Based on these conditions, it is necessary to have a risk analysis of natural disasters that have the potential to occur, so that alternative disaster management can be made. This study aims to determine the potential for disaster risk in Buleleng Regency and how the priorities for handling from the level of risk and intensity of the threat. The method used in this study is an analysis of potential natural disaster risks obtained from a combination of hazard, vulnerability and capacity data. Threat data was obtained from data released by BNPB from the inarisk.bnpb.go.id, while vulnerability and capacity data were obtained from interviews and secondary data from related agencies. The entire data obtained was then conducted an FGD with BPBD Buleleng Regency which was then analyzed descriptive qualitative. Based on the research results, it was found that the potential for disasters in Buleleng Regency were categorized into 2, namely: disasters that have a high risk impact are Earthquakes and Tsunamis, while disasters with high incident intensity are floods, extreme weather, extreme waves and abrasion, drought, landslides, flash floods and fires.
Validation of Satellite Rainfall Product (GPM-IMERG) an Bali and Nusa Tenggara: A Comparison of Normal Seasons, El Nino and La Nina Events Tulistiawan, Putu Eka; Karang, I Wayan Gede Astawa; Osawa, Takahiro
JURNAL GEOGRAFI Vol. 15 No. 2 (2023): JURNAL GEOGRAFI
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/jg.v15i2.44967

Abstract

Bali and Nusa Tenggara are regions where monsoonal wind changes and strange interactions between the ocean and atmosphere influence rainfall. The purpose of this research is to evaluate Integrated Multi-Satellite Retrievals for GPM (IMERG) rainfall data using in-situ observations from Bali and Nusa Tenggara, Indonesia, while considering seasonal variations and the El Nino-Southern Oscillation (ENSO) phenomenon. The study combines rainfall data from synoptic stations with rain gauge measurements over ten years, from January 2012 to December 2021, to obtain more accurate verification results. The study's findings indicate that, apart from the transitional seasons, IMERG data provides substantial estimates of monthly rainfall accumulation with low error values for both light and heavy rainfall. The study also reveals that the islands' complexity and topography can impact each province's validation values. The verification results show excellent accuracy in flat terrain areas and moderate elevations, while performance decreases in regions with high altitudes. These findings are significant because IMERG data can estimate rainfall for regions lacking monitoring stations during specific seasons and active ENSO conditions. Thus, this information can serve as a valuable tool to address the issue of data unavailability in hard-to-access areas and contribute to optimizing water resource management and weather-related disaster mitigation. Keywords: Validation, Rainfall, IMERG, ENSO
ESTIMATION OF TIDAL ENERGY DISSIPATION AND DIAPYCNAL DIFFUSIVITY IN THE INDONESIAN SEAS I Wayan Gede Astawa Karang; Fumihiko Nishio; Takahiro Osawa
International Journal of Remote Sensing and Earth Sciences Vol. 7 No. 1 (2010)
Publisher : BRIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.ijreses.2010.v7.a1542

Abstract

The Indonesian Seas separating the Indian Ocean from the West Pacific Oceanare representative regions of strong tidal mixing in the world oceans. In the present study,we first carry out numerical simulation of the barotropic tidal elevation field in theIndonesian Seas using horizontally two-dimensional primitive equation model. It is foundthat, to reproduce realistic tidal elevations in the Indonesian Seas, the energy lost by theincoming barotropic tides to internal waves within the Indonesian seas should be taken intoaccount. The numerical experiments show that the model predicted tidal elevations in theIndonesian Seas best fit the observed data when we take into account the baroclinic energyconversion in the Indonesian Seas ~86.1 GW for the M2 tidal constituent and ~134.6 GWfor the major four tidal constituents (M2, S2, K1, O1). For this baroclinic energy conversion,the value of Kñ averaged within the eastern area (Halmahera, Seram, Banda and MalukuSeas), the western area (Makassar and Flores Seas), and the southern area (Lombok Straitand Timor Passage) are estimated to be ~23 × 10-4 m2s-1, ~5 × 10-4 m2s-1, and ~10× 10-4m2s-1, respectively. This value is about 1 order of magnitude more than assumed for theIndonesian Seas in previous ocean general circulation models. We offer this study as awarning against using diapycnal diffusivity just as a tuning parameter to reproduce largescalephenomena.
STUDY ON VARIABILITY MECHANISM OF 1997/1998 ENSO IN PACIFIC OCEAN AND EASTERN PART OF INDONESIAN ARCHIPELAGO Luh Made Chandra; Astiti Ratnasari; I Gede Hendrawan; I Wayan Gede Astawa Karang; Yasuhiro Sugimori
International Journal of Remote Sensing and Earth Sciences Vol. 3 (2006)
Publisher : BRIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.ijreses.2006.v3.a1210

Abstract

El Nino-Southern Oscillation (ENSO) is one of the most important climate anomalies humans are concerned about. It brought many changes in physical of the ocean. This phenomenon causes changes in sea surface temperature (SST). During El-Nino condition, the SST is much warmer in eastern side of Pacific Ocean than normal condition, and during La-Nina event the SST in eastern Pacific Ocean is cooler than normal condition. From July 1997, the warm water has spread from the western Pacific Ocean towards the east and the winds in the western Pacific were blowing strongly towards the east, pushing the warm water eastward on December 1997 and January 1998. Strong La-Nina condition water extended farther westward than usual. In October 1997, during El-Nino event 1997, the SST in eastern part of Indonesia Archipelago was cooler. The varies of SST in PacificOcean during El-Nino 1997 was influenced the Indonesian Through Flow (ITF). During El-Nino event 1997, surface current flown strongly from Pacific Ocean to the Indian Ocean On the other hand, since March 1998 the surface current inversed from Indonesian Sea to the Pacific Ocean.
THE USE OF SATELLITE REMOTE SENSING (ALOS SATELLITE DATA) I Wayan Gede Astawa Karang; I Gede Hendrawan
International Journal of Remote Sensing and Earth Sciences Vol. 4 (2007)
Publisher : BRIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30536/j.ijreses.2007.v4.a1223

Abstract

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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 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 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 Yulianto Suteja