Selat Sunda merupakan selat dengan kondisi fisik dinamis yang menjadi menjadi jalur sirkulasi massa air di perairan Indonesia petemuan Armondo dan Arlindo. Perairan ini didominasi dari Samudera Hindia dengan dinamika perairan yang sebagian besar dipengaruhi oleh angin musim, hal ini dapat memicu percampuran massa air. Penelitian ini bertujuan untuk mengetahui karakteristik massa air di Selat Sunda dan perairan lepasnya. Pengambilan data dilakukan pada bulan November 2019 dan data model diperoleh dari situs CMEMS (2015-2019). Pengolahan data menggunakan software Ocean Data View (ODV) dengan metode sebaran vertikal, melintang dan diagram TS. Hasil penelitian menunjukkan temperatur di Selat Sunda relatif lebih tinggi dengan kisaran 29-30,2oC. Sebaran salinitas dan densitas di Samudera Hindia lebih tinggi dengan nilai masing-masing 35-35,2 ‰dan 22,20 kg/m3. Tipe massa air didominasi dari Samudera Hindia terdiri dari Bengal Bay Water (BBW), South Indian Central Water (SICW), Antartic Intermediate Water (AAIW) dan Indonesian Upper Water (IUW). Dua jenis massa air berasal dari Samudera Pasifik yakni Pacific Equatoral Water (PEW) dan Western North Pacific Central Water (WNPCW). Variabilitas massa air menunjukkan pola yang relatif serupa. Sebaran temperatur tertinggi terjadi pada musim peralihan 2 (30,2oC) dan terendah di musim timur (29,2oC). Sebaran salinitas permukaan tertinggi terjadi pada musim peralihan 2 (32,87‰) dan terendah pada musim peralihan 1 (31,74‰). Sunda Strait is a strait with dynamic physical condition that crossed by Armondo and Arlindo. These waters are dominated by Indian Ocean with dynamics of waters which are largely influenced by monsoons, its condition give an example of mixing water mass. This research aims to determine characteristics and variability of water mass. This study was carried out in November 2019 and satellite data was obtained from CMEMS website (2015-2019). Processing data was performed using software Ocean Data View (ODV) by methods scatter distribution, cross section and TS diagram. The result show that temperature in the Sunda Strait was relatively higher with a range 29-30.2oC. The distribution of salinity and density in the Indian Ocean is higher with values of 35-35.2 o/oo and 22.2 kg/m3. TS diagram shows that water mass dominated by the Indian Ocean consists of Bengal Bay Water (BBW), South Indian Central Water (SICW), Antartic Intermediate Water (AAIW) and Indonesian Upper Water (IUW). Two type of water mass from Pacific Ocean are Pacific Equatorial Water (PEW) and Western North Pacific Central Water (WNPCW). Variability of water mass shows a similar pattern. The highest temperature distribution occurred in transitional season 2 (30.2oC) and the lowest in east season (29.2oC). The highest distribution of salinity occurred in transitional season 2 (32.87 o/oo) and the lowest in transitional season 1 (31.74 o/oo).

Hydrographic measurements recently acquired along the thalweg of the Lifamatola Passage combined with historical moored velocity measurements immediately downstream of the sill are used to study the hydraulics, transport, mixing, and entrainment in the dense overflow. The observations suggest that the mean overflow is nearly critical at the mooring site, suggesting that a weir formula may be appropriate for estimating the overflow transport. Our assessment suggests that the weir formulas corresponding to a rectangular, triangular, or parabolic cross section all result in transports very close to the observation, suggesting their potential usage in long-term monitoring of the overflow transport or parameterizing the transport in numerical models. Analyses also suggest that deep signals within the overflow layer are blocked by the shear flow from propagating upstream, whereas the shallow wave modes of the full-depth continuously stratified flow are able to propagate upstream from the Banda Sea into the Maluku Sea. Strong mixing is found immediately downstream of the sill crest, with Thorpe-scale-based estimates of the mean dissipation rate within the overflow up to 1.1 × 10⁻⁷ W kg⁻¹ and the region-averaged diapycnal diffusivity within the downstream overflow in the range of 2.3 × 10⁻³ to 10.1 × 10⁻³ m² s⁻¹. Mixing in the Lifamatola Passage results in 0.6–1.2-Sv (1 Sv ≡ 10⁶ m³ s⁻¹) entrainment transport added to the overflow, enhancing the deep-water renewal in the Banda Sea. A bulk diffusivity coefficient estimated in the deep Banda Sea yields 1.6 × 10⁻³ ± 5 × 10⁻⁴ m² s⁻¹, with an associated downward turbulent heat flux of 9 W m⁻².

Information about wind variations and future wind conditions is essential for a monsoon domain such as the Northwest Pacific (NWP) region. This study utilizes 10 Generalized Circulation Models (GCM) from CMIP6 to evaluate near-future wind changes in the NWP under various climate warming scenarios. Evaluation against the ERA5 reanalysis dataset for the historical period 1985–2014 reveals a relatively small error with an average of no more than 1 m/s, particularly in the East Asian Marginal Seas (EAMS). Future projections (2026–2050) indicate intensified winds, with a 5–8% increase in the summer season in the EAMS, such as the Yellow Sea, East Sea, and East China Sea, while slight decreases are observed in the winter period. Climate mode influences show that winter El Niño tends to decrease wind speeds in the southern study domain, while intensifying winds are observed in the northern part, particularly under SSP5-8.5. Conversely, summer El Niño induces higher positive anomalous wind speeds in the EAMS, observed in SSP2-4.5. These conditions are likely linked to El Niño-induced SST anomalies. For the application of CMIP6 surface winds, the findings are essential for further investigations focusing on the oceanic consequences of anticipated wind changes such as the ocean wave climate, which can be studied through model simulations.