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

Abstract

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 (L_T), frekuensi Brunt Vaisala (N), disipasi energi kinetik turbulen (ε) dan estimasi nilai difusivitas eddy vertikal (K_Z). 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 K_z 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.