Distribusi Suhu, Salinitas dan Densitas di Lapisan Homogen dan Termoklin Perairan Selat Makassar

Abstract

Selat Makassar merupakan salah satu celah penghubung antara Samudera Pasifik dan Samudera Hindia dengan karakteristik oseanografi lebih dipengaruhi oleh Samudera Pasifik melalui sirkulasi Arlindo. Sirkulasi Arlindo bersama dengan variasi pergerakan angin muson akan berpengaruh terhadap distribusi suhu, salinitas dan densitas di lapisan homogen dan termoklin. Penelitian ini bertujuan mengkaji distribusi suhu, salinitas dan densitas di lapisan homogen dan termoklin perairan Selat Makassar. Penelitian ini dilaksanakan pada bulan Oktober 2015. Data diperoleh dari Pusat Penelitian dan Pengembangan Sumber Daya Laut dan Pesisir (P3SDLP) dengan data primer berupa data suhu, salinitas, densitas dan kedalaman menggunakan instrumen CTD. Stasiun pengambilan data terdiri dari 18 stasiun pengambilan data berdasarkan metode purposive sampling. Data yang diperoleh kemudian dianalisis menggunakan metode analisis statistik deskriptif. Hasil menunjukkan bahwa ketebalan lapisan homogen antara 19,5-68,5 m. Ketebalan lapisan termoklin bervariasi antara 50-220 m. Variabilitas ketebalan lapisan homogen dan lapisan termoklin disebabkan beberapa faktor seperti tekanan angin, pemanasan matahari, transpor massa air, dan aktivitas gelombang internal. Sebaran nilai suhu di lapisan homogen bervariasi antara 25,35-29,94 oC. Suhu permukaan laut cenderung lebih tinggi di bagian utara Selat Makassar. Suhu di lapisan termoklin berkisar antara 12,09-29,22 oC. Salinitas di lapisan homogen bervariasi antara 33,91-34,59 ‰. Nilai salinitas permukaan laut cenderung lebih tinggi di selatan Selat Makassar. Hal ini diduga disebabkan pengaruh dari Laut Jawa dan Laut Flores. Salinitas di lapisan termoklin bervariasi antara 34,18-34,88 ‰. Nilai densitas di lapisan homogen bervariasi antara 20,93-22,93 kg/m3. Nilai densitas di lapisan termoklin bervariasi antara 21,47-26,13 kg/m3. Gradien rata – rata temperatur lapisan termoklin antara 0,07-0,14 oC/m. Gradien rata – rata temperatur berbanding terbalik dengan ketebalan lapisan termoklin. Makassar Strait is a pathway that connected the Pacific Ocean and the Indian Ocean with oceanographic characteristics more influenced by the Pacific Ocean through Arlindo. Arlindo circulation and movement variations of the monsoon will affect the distribution of temperature, salinity and density in homogeneous and thermocline layer. The aims of this study is were to assess the distribution of temperature, salinity and density in homogeneous and thermocline layer of Makassar Strait. This research was conducted in October 2015. Data were obtained from the Pusat Penelitian dan Pengembangan Sumber Daya Laut dan Pesisir (P3SDLP) with the primary data that were temperature, salinity, density and depth by using CTD instruments. Data measurement station consists of 18 stations based on purposive sampling method. Data were analyzed using descriptive statistical analysis method. The results showed that the homogeneous layer thickness were vary with range from 19.5 m to 68.5 m. Thermocline layer thickness between 50-220 m. Variability homogeneous layer thickness and the thermocline were caused by several factors such as air pressure, solar heating, water mass transport, and internal wave activity. The distribution of temperature in a homogeneous layer were vary with range from 25.35 ° C to 29.94 ° C. Sea-surface temperatures tend to be higher in the northern of Makassar Strait. Temperatures in the thermocline layer ranged from 12.09 °C to 29.22 °C. Salinity in a homogeneous layer werer vary with range from 33.91 ‰ to 34.59 ‰. Sea surface salinity were higher in the southern of Makassar Strait. This was assumed due to the influence of the Java Sea and Flores Sea. Salinity in the thermocline layer were vary with range from 34.18 ‰ to 34.88 ‰. The density in a homogeneous layer vary among 20.93-22.93 kg/m3. The density in the thermocline layer were vary with range from 21.47 kg/m3 to 26.13 kg/m3. Average gradient temperature of the thermocline layer were vary with range from 0.07 °C/m to 0.14 °C/m. Average gradient of temperature was inversely proportional to the thickness of the thermocline layer.

Shadow zone mapping using parabolic equation method in the Bali Strait Waters

“…A negative value indicates an inverse relationship between the average temperature gradient and the thickness of the thermocline region [11]. In the East Season, The sun gives more heat to the Asian continent, affecting the surrounding waters [12].…”

Seasonal variation of mixed layer depth and thermocline thickness from the ctd argo float data in the Southern Makassar Strait

“…The variation of the thermocline layer's thickness depends on the upper and lower limits of the thermocline layer. Determination of the thickness of the thermocline layer in this study uses the temperature gradient formula and can be calculated using the following formula [10]: After obtaining the temperature gradient value, then identification of the water mass layer refers to Wyrtki [1] where the temperature gradient is 0.05 °C/m as the upper and lower limits of the thermocline layer. The distribution of the upper and lower limits of the thermocline can determine the depth of the mixed layer and the depth of the deep (homogeneous) layer.…”

Characteristics of North Pacific water masses in the Bali Sea

“…The lower limit of the depth of the thermocline layer is in the range of 190-504 meters. According to Putra et al [10], the variation in the upper limit of the IOP Publishing doi:10.1088/1755-1315/1251/1/012039 6 thermocline layer at each station is due to internal wave activity. Variations in the depth of the lower limit of the thermocline layer are influenced by the movement of deep water masses with low temperatures and high salinity.…”