Percampuran vertikal di Perairan Laut Maluku dan Talaud pada bulan Februari 2021

Purwandana, Adi; Iskandar, Mochamad Riza; Kusmanto, Edi; Fadli, Muhammad; Santoso, Priyadi Dwi; Corvianawatie, Corry; Muhadjirin, Muhadjirin; Wattimena, Marlin Chrisye; Wang, Zheng

doi:10.14203/oldi.2021.v6i2.363

Cited by 5 publications

(7 citation statements)

References 13 publications

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Section: Methodsmentioning

confidence: 99%

“…In addition to ISW breaking events, vertical mixing is also influenced by wind stress at the ocean surface, tidal currents, density differences, and submesoscale topographic eddies (Srinivasan et al, 2017;Webb & Suginohara, 2001). The elevated values in the onshore/shallow region part are possible as the area is one of the hotspots for intensive vertical mixing in the Maluku Sea, according to the results of prior research conducted by (Yuan et al, 2022;Purwandana, Iskandar, et al, 2021;Ffield & Gordon, 1992). This hypothesis is reliable due to the fact that the southeastern coastal waters of northern Sulawesi Island are exposed regularly to ISW breaking events (Purwandana & Cuypers, 2023), which is a potential source of energy for mixing in the coastal waters (Purwandana et al, 2022;Bourgault et al, 2008).…”

Section: Spatial Variabilitymentioning

confidence: 97%

“…This method has been categorized as an indirect method, different from the direct method which uses vertical current shear that is directly related to the turbulence. In this study, an improved Thorpe Method was used, which has been proven comparable to direct estimates in the Indonesian seas(Purwandana et al, 2020) and widely used in local waters(Purwandana, 2022; Purwandana, Cuypers, et al., 2021;Purwandana, Iskandar, et al, 2021;Sani et al, 2021).External forcing coming from tidal-driven currents can lead to turbulent events due to the vertically sheared current profile. In the water column, this event is eventually manifested as a gravitationally unstable density profile.…”

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confidence: 99%

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Vertical Mixing in The Onshore Region of The Northwestern Maluku Sea, Indonesia

Priyono,

Purwandana,

Kusmanto

et al. 2023

omni.akua

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Spatio-temporal dynamics of vertical mixing in the northwestern Maluku Sea were quantified using the Thorpe Method from archived CTD datasets collected during the expedition of Baruna Jaya VIII RCO-LIPI on November 12–13, 2000. The turbulent kinetic energy (TKE) dissipation rate and vertical eddy diffusivity values inspected the variability of mixing properties. Higher values for both parameters were found at the shallower bathymetry, which is less than 1000 m deep. This suggests that the water column is vertically unstable as a result of being often subjected to internal solitary wave (ISW) breaking events. The strong temporal variability observed from the density profile also indicated a strong impact on internal tide activity. There was temporal fluctuation of the TKE dissipation rate as well as vertical eddy diffusivity values following semidiurnal periodicity, with typical variability up to one order of magnitude for both the dissipation and diffusivity. The range of fluctuation is [6.8×10-8 ? 9.3×10-7] W kg-1 and [1.5×10-5 – 5.4×10-3] m2s-1, respectively in the upper 200 m depth. This water generated a high dissipation rate and vertical diffusivity when regularly exposed to internal solitary waves breaking from the Lifamatola Passage.Keywords: mixing properties, CTD data, turbulent kinetic energy, vertical eddy diffusivity

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Section: Methodsmentioning

confidence: 99%

Section: Spatial Variabilitymentioning

confidence: 97%

mentioning

confidence: 99%

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Vertical Mixing in The Onshore Region of The Northwestern Maluku Sea, Indonesia

Priyono,

Purwandana,

Kusmanto

et al. 2023

omni.akua

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“…The Indonesian maritime continent links two oceans, the Pacific Ocean and the Indian Ocean [1], [2], via its throughflow, known as the Indonesian throughflow (ITF). The throughflow transports water masses from the Pacific into the Indian Ocean via two entry passages, the western and eastern routes.…”

Section: Introductionmentioning

confidence: 99%

Transformation of South Pacific Water Masses in the Halmahera Sea

Prasetyo,

Wicaksono,

Purwandana

et al. 2024

BIO Web Conf.

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The Halmahera Sea is part of the eastern entry route of the Indonesian throughflow (ITF) passages. The characteristics and transformation of the South Pacific water masses are presented based on the HYCOM model (Hybrid Coordinate Ocean Model) and direct observations of CTD (Conductivity, Temperature, Depth) acquired during the East Indonesian Expedition in October 2017 using RV Baruna Jaya VIII. This study is aimed at characterizing the typical water masses observed in the Halmahera Sea and tracking the transformation of the South Pacific water masses in the region. The results show that there was an indication of strong vertical mixing of maximum salinity of the South Pacific thermocline water masses, i.e., South Pacific Subtropical Water (SPSW), from ~35.2 PSU at isopycnal 24 – 25 kg m-3 becomes ~34.8 PSU in the Southern Halmahera Strait (around 200 km from the entry passage, the Northern Halmahera Strait), and rapidly decreases from the Southern Halmahera Strait and Obi Strait to become 34.6 PSU in the Maluku Sea. These preliminary findings suggest a strong mixing in the southern Halmahera Strait and Obi Strait.

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“…Perairan Selat Lifamatola merupakan salah satu lintasan Arlindo dimana massa air Samudera Pasifik mengalami percampuran intensif akibat tingginya Gelombang Internal sebagai akibat adanya Sill dan pengaruh energi pasang surut (Van Aken et al, 2009;Tan et al, 2020;Purwandana et al, 2021). Selat Lifamatola juga dikenal sebagai embrio gelombang internal soliter (Purwandana et al, 2021). Sebagai bagian dari lintasan Arus Lintas Indonesia, massa air Samudera Pasifik masuk melintasi perairan ini (Gordon, 2005;Van Aken et al, 2009).…”

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Percampuran Vertikal Massa Air Lapisan Pertengahan Perairan Lifamatola pada Bulan Maret 2009

Harsono,

Purwanto,

Wirasatriya

et al. 2023

Bul. Oseano. Mar.

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Perairan Lifamatola menarik dikaji selain sebagai lintasan Arlindo juga proses percampuran massa airnya terjadi secara intensif. Tujuan penelitian ini adalah mengkaji percampuran turbulen di Perairan Lifamatola pada Maret 2009. Data salinitas, temperatur dan kedalaman diperoleh dari program Tropical Ocean Climate Study (TOCS) tahun 2009, kerjasama Badan Pengkajian Penerapan Teknologi (BPPT) dan Jamstec (Japan of Marine Science Earth and Technology) Jepang menggunakan RV. Kaiyo. Analisis meliputi analisis skala Thorpe (LT), frekuensi Brunt Vaisala (N), disipasi energi kinetik turbulen (ε) dan estimasi nilai difusivitas eddy vertikal (KZ). Hasil identifikasi karakteristik massa air Samudera Pasifik, North Pacific Intermediate Water (NPIW) pada perairan ini S-max tidak terlihat karena diduga sudah bertranformasi menjadi massa air dengan karakteristik yang baru akibat proses percampuran. Hasil perhitungan terhadap nilai frekuensi Brunt Vaisala, pada lapisan termoklin diperoleh nilai N2 tertinggi yaitu 0,05-0,15 s-1 pada kedalaman 100 m dan kedalaman 200 m, sementara lapisan tercampur berkisar 0,0- 0,01 s-1 dan lapisan dalam 0-0,005 s-1. Lapisan termoklin memiliki nilai Td -5 m sampai 3 m, lapisan dalam berkisar -4 m sampai 5 m dan lapisan dalam berkisar -13m sampai 19 m. Nilai rata-rata disipasi energi kinetik turbulen (ε) dari semua lapisan yaitu sebesar 3.29 x 10-9 Wkg-1. Hasil dari rata-rata menunjukkan bahwa semakin bertambahnya kedalaman nilai disipasi energi kinetik turbulen (ε) semakin menurun. Nilai difusivitas paling tinggi terjadi pada lapisan termoklin dan menurun dengan semakin bertambah nya kedalaman. Nilai Kz pada lapisan permukaan antar sampling berbeda-beda, terjadi akibat Gelombang Internal dan aktivitas pasang surut. Lifamatola waters are interesting to study apart from being the Arlindo trajectory as well as the process of intensive mixing. The aim of this research is to examine turbulent mixing in Lifamatola Waters in March 2009. Salinity, Temperature and Depth data were obtained from the Tropical Ocean Climate Study (TOCS) program in 2009, a collaboration between the Agency for the Assessment of the Application of Technology (BPPT) and Japan of Marine Science Earth and Technology uses RV. Kaiyo. The analysis includes Thorpe scale analysis (LT), Brunt Vaisala frequency (N), turbulent kinetic energy dissipation (ε) and estimation of vertical eddy diffusivity (KZ) values. The results of identifying the characteristics of the Pacific Ocean wate mass, North Pacific Intermediate Water (NPIW) in these waters, S-max is not visible because it is thought to have been transformed into a water mass with new characteristics due to the mixing process. The results of the calculation of the Brunt Vaisala frequency value, in the thermocline layer, the highest N2 value was obtained, namely 0.05-0.15 s-1 at a depth of 100 m and a depth of 200 m, while the mixed layer ranged from 0.0-0.01 s-1 and inner layer 0-0.005 s-1. The thermocline layer has a Td value of -5 m to 3 m, the inner layer ranges from -4 m to 5 m and the inner layer ranges from -13m to 19 m. The average value of turbulent kinetic energy dissipation (ε) from all layers is 3.29 x 10-9 Wkg-1. The results of the average show that as the depth increases the dissipation value of turbulent kinetic energy (ε) decreases. The highest diffusivity value occurs in the thermocline layer and decreases with increasing depth. The Kz value in the surface layer varies between sampling, occurring due to internal waves and tidal activity.

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Percampuran vertikal di Perairan Laut Maluku dan Talaud pada bulan Februari 2021

Cited by 5 publications

References 13 publications

Vertical Mixing in The Onshore Region of The Northwestern Maluku Sea, Indonesia

Vertical Mixing in The Onshore Region of The Northwestern Maluku Sea, Indonesia

Transformation of South Pacific Water Masses in the Halmahera Sea

Percampuran Vertikal Massa Air Lapisan Pertengahan Perairan Lifamatola pada Bulan Maret 2009

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