SIMULATION OF TIDE AND SEASONAL CIRCULATION IN SUNDA STRAIT BY USING DELFT3D MODEL

• Main Author: STELLA BARTHOLOMEUS (NIM : 12914024), BERNADETHA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26081
• Institution: Institut Teknologi Bandung

<p align="justify"> Sunda Strait is an important strait by reason of connecting Sumatera dan Java Island. This strait is also unique as much as it plays role in water exchange between two differences characteristic of Indian Ocean and Java sea. Indian Ocean is a wide and deep sea but Java Sea is narrow and shallow water hence this region is interesting. The aim of this study is to analyze the dynamic of current in Sunda Strait. <br /> <br /> In this research, DELFT3D model was used with simulation forcing conditions by tides from Tide Model Driver (TMD) and wind from European Center for Medium Range Forecast (ECMWF). Bathymetry data from DisHidros-TNI AL and GEBCO 30” was also used for the simulation. Elevation data from Badan Informasi Geospasial (BIG) and current velocities data from Badan Litbang Kelautan dan Perikanan that associated with The first Institute of Oceanography, SOA, China in Pertiwi's (2017) was used as an observation data. In this study, several scenarios were done including the current simulation that was only generated by tides in December 2015 then seasonal flow simulations with tidal and wind generation in the northwest monsoon (December 2015) and southeast monsoon (July 2015). <br /> <br /> Model verification was done in December 2015 with tide as the only forcing condition and shows very good results with R2 and RMSE respectively in Panjang Station (0.93; 0.1 m) and Kota Agung (0.94; 0.11 m). The comparison of west-eastern current with observation data shows good results with R2 (0.56) and RSME (0.15 m/s), however the comparison of north-southern current with observation data shows very good results with R2 (0.9) and RMSE (0.17 m/s). <br /> <br /> Based on Formzahl map, tidal’s type in Sunda Strait is mixed tide, prevailing semidiurnal on the southwest and mixed tide prevailing diurnal on the northeast. In the northeast and southwest of Sunda Strait, the dominant tidal constituent respectively are K1 and M2 with its amplitude 0,3 m. K1 propagates southwestward while M2 propegates northeastward. There is something unique in M2 cophase map because of the M2 front phase. The simulation shows that the currents move to Java Sea (high tide) and Hindia Ocean (low tide). Maximum current velocity reach 2.2 m/s in spring tide condition in narrow gap. The tidal residual currents predominantly going to southwestward. Current dynamic with wind forcing condition have the same results and shows that tide forcing condition is more dominant in Sunda Strait. But the mean surface currents shows the effect of the wind, in northwest monsoon the currents move eastward and in southeast monsoon the currents move westward with greater magnitude because the wind direction is similar with the tidal residual current direction. <p align="justify">