SIMULASI STORM-SURGE DI SELAT BANGKA DENGAN MENGGUNAKAN COUPLED ADCIRC DAN SWAN MODEL

Sofian, Ibnu

MAJALAH ILMIAH GLOBE
Vol 14, No 2 (2012)

Simulasi storm-surge di selat Bangka dilakukan dengan menggunakan coupled model ADvanced CIRCulation (ADCIRC) dan model gelombang generasi ketiga SWAN. Simulasi ini dilakukan untuk melihat seberapa tinggi bahaya badai terhadap keamanan PLTN yang akan dibangun di Pulau Bangka. Secara umum, hasil model relatif sesuai dengan hasil pengukuran pasut. Namun hasil model cenderung over-estimate 10 - 30 cm, terutama pasca terjadinya badai Hagibis dan Mitag. Ketinggian gelombang di bagian utara Selat Bangka lebih tinggi dari tinggi gelombang di bagian tengah dan selatan. Meskipun tinggi gelombang hanya beberapa puluh sentimeter, namun stres angin dan gelombang laut, perubahan tekanan Atmosfer di permukaan dan arus permukaan yang kuat dapat menyebabkan kenaikan tinggi muka laut yang ekstrim lebih dari 70 cm. Permukaan laut (sea level) semakin tinggi ketika Badai Hagibis dan Mitag semakin kuat, dan mencapai puncak pada 21 dan 22 November 2007. Selanjutnya kekuatan badai melemah dan bergerak ke utara, ketinggian sea level turun, meskipun permukaan air laut masih tinggi di akhir periode badai. Sebagai penutup, tinggi sea level ekstrim ini dapat mempertinggi risiko terjadinya rob di Pulau Bangka.Kata Kunci: Simulasi, Storm-Surge, Bangka, Coupled Model, ADCIRC, SWAN ABSTRACTSimulation of storm-surge at the Bangka Strait was carried out using coupled models which are ADvanced CIRCulation model (ADCIRC) and the 3th generation of wave model (SWAN). The model simulation was carried out to investigate the impact of storm surges on the Nuclear Power Plant that planned in Bangka Island. In general, the model results relatively match with the tide gauge observation. However, the - sea level modeled tends to over-estimate about 10cm to 30cm, especially during the post-Hagibis and Mitag Storms. The wave height in the northern part of Bangka Strait was higher than the one in southern and central of Bangka Strait. Eventhough, the wave height is only several tens centimeters, the wave and wind stresses, surface pressure changes and the current speed can elevate the extreme sea level rise for more than 70cm. The sea level is getting higher when the Mitag and Hagibis are getting stronger, and reached to peak in 21 to 22 November 2007. The storm surge was weaker and moved to the north, and sea level drops, thereafter. Finally, this extreme sea level rise heightens the coastal flooding risk in the Bangka Island.Keywords: Simulation, Storm-Surge, Bangka, Coupled Model, ADCIRC, SWAN