Denny Nugroho Sugianto

Waves Induce Sediment Transport at Coastal Region of Timbulsloko Demak

Waves have variation of length and period. This influenced by seasonal variation. Impacts of seasonal variation related to wave is playing important roles in sediment transport mechanism and coastal changes. This condition not only treats coastal area but also decreases economic capacity of community. This research aim to determine different seasonal based on Indonesia Northwest-Northeast monsoon and Southeast-Southwest monsoon and theirs relation to sediment transport. Area of study is suffered by 938.73 H of abrasion. Conducted by CERC methods, transforming BMKG Ahmad Yani wind database (2005-2015) into wave’s data of seasonal variation and using field measurement recorded by ADCP. Definitely, maximum speed of wind is reached at 23 knots from December to February, wind direction predominantly from North West direction. Range of significant Wave Height (Hs) all season is 24.66-30.32 cm and Significant Wave period (Ts) count at 3.64-3.78 sec. Net of sediment volume annual 72,353.40 m3 year -1 and sediment movement pattern is forwarding from west to east direction. Correlation between breaking waves and sediment transport is linier.

Influence of ENSO and IOD to Variability of Sea Surface Height in the North and South of Java Island

Indonesia is one of the largest archipelagic countries in the world. Besides being in the tropics, these waters are also located between two continents and two oceans that making this area are heavily influenced by the global atmospheric phenomena such as El Nino Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD). Sea level rise is one of the main threats faced by Indonesia and other island countries in the world. Not only global warming, sea level rise in the tropics also caused by inter annual variability such as ENSO and IOD. This research has been aimed to determine the influence of ENSO and IOD to variability of sea surface height in the north and south of Java. This research used Satellite altimetry data were constructed by multi-mission satellite. These results showed that the sea level anomaly generally inversely related to ENSO and Dipole Mode Index. The phenomenon that most influence a decrease sea level anomaly in the study area is a phenomenon IOD + and the phenomenon that most influenced the increase sea level anomaly is La Nina. South of Java is area that has the large effect of changes in sea levels than north of Java. During La Nina, sea level anomaly can be increase up to 0.3 m and sea level anomaly can be decrease up to -0.28 m during IOD+.

The Influence of Madden Julian Oscillation on the Formation of the Hot Event in the Western Equatorial Pacific

Hot event (HE) is the high SST phenomena higher than about 30C, occur in an area of more than 2×106 km2 and last for a period more than 6 days. HE develops only under the condition of high solar radiation and low wind speed. The indication of the relation between HE and MJO has been described in the previous study for one HE case. In the present study, the more case of MJO-HE relation is collected for the period of 2003-2011 and the possible mechanisms is examined. New Generation Sea Surface Temperature for Open Ocean (NGSSTO-Global-V2.0a) was used to identify HEs. Precipitation from TRMM were bandpass filtered with cut off period of 30-60 days for MJO identification. Observation data from TAO/TRITON buoy were used for investigating the possible mechanism of MJO-HE relation. Off 48 HE cases located along the equatorial band, the development of 29 HE cases was related to the suppressed phase of MJO whereas the high solar radiation occurred. High precipitation during the active phase of MJO may contribute to stabilize the upper mixed layer. The stable upper water column fasten the heating process during the suppressed phase of MJO, generating HE.

Wave Transformation for International Hub Port Planning (Transformasi Gelombang untuk Perencanaan Pelabuhan Hub Internasional)

Indonesia merupakan salah satu negara kepulauan terbesar di dunia sehingga peran pelabuhan sangat vital dalam pembangunan ekonomi. Pelabuhan bukan hanya sekedar sebagai pelengkap infrastruktur, melainkan harus direncanakan dan dikelola dengan baik serta memperhatikan fenomena dinamika perairan laut seperti pola gelombang laut. Data gelombang laut menjadi faktor penting dalam perencanaan tata letak dan tipe bangunan pantai karena dipengaruhi oleh tinggi gelombang signifikan, tunggang pasang surut dan transformasi gelombang. Penelitian ini mengalisis karaketristrik dan bentuk transformasi gelombang untuk perencanaan Pelabuhan Hub Internasional, sebagai studi kasus adalah pelabuhan di Kuala Tanjung, Kabupaten Batu Bara. Pelabuhan di Kuala Tanjung merupakan salah satu dari 2 pelabuhan hub internasional yang direncanakan akan dibangun oleh pemerintah Indonesia. Metode yang digunakan adalah metode kuantitatif yang dilakukan dengan perhitungan statistik dan pemodelan matematik dengan modul hydrodinamic dan spectral wave untuk mengetahui arah penjalaran dan transformasi gelombang. Hasil dari data ECMWF selama 1999–Juni 2014, diketahui tinggi gelombang signifikan (Hs) maksimum mencapai 1,69 m dan periode maksimum 8 detik. Karakteristik gelombang termasuk klasifikasi gelombang laut transisi dengan nilai d.L -1 berkisar anrata 0,27–0,48 dan berdasarkan periodenya diklasifikasikan sebagai gelombang gravitasi.Transformasi gelombang terjadi akibat pendangkalan dengan koefesian pendangkalan Ks 0,93–0,98 dan proses refraksi gelombang dengan koefesien Kr 0,97–0,99. Tinggi gelombang pecah H b sebesar 1,24 meter dengan kedalaman gelombang pecah d b sebesar 1,82 meter. Efektifitas desain bangunan terminal di Pelabuhan Kuala Tanjung secara keseluruhan untuk sepanjang musim sebesar 79,8% atau dapat dikatakan cukup efektif dalam meredam gelombang. Kata kunci: t ransformasi gelombang, tinggi dan periode gelombang, pelabuhan Indonesia is one of the largest archipelagic countries in the world, therefore port has vital role in economic development. Port is not just as a complement to the infrastructure, but it must be planned and managed properly and attention to the dynamics of marine phenomena such as ocean wave patterns. Ocean wave data become important factors in planning coastal building, since it is influenced by wave height, tides and waves transformation. The purpose of this study was to analyse characteristic and forms wave transformations for planning of international hub port at Kuala Tanjung, Baru Bara District North Sumatra. This port is one of two Indonesian governments plan in the development of international hub port. Quantitative method was used in this study by statistical calculations and mathematical modeling with hydrodinamic modules and spectral wave to determine the direction of wave propagation and transformation. Results show that based on ECMWF data during 1999-June 2014, known significant wave height (Hs) maximum of 1.69 m and maximum period (Ts) of 8 secs. The classification wave characteristics iswave transition (d.L -1 : 0.27–0.48) and by the period are classified as gravitational waves. Wave transformation occurs due to the soaling, withKs 0.93–0.98 and the wave refraction Kr 0.97–0.99. Whereas H b of 1.24 meters andd b 1.82 meters. The effectiveness of the design of the terminal building at the Port of Kuala Tanjung overall for the season amounted to 79.8%, which is quite effective in reducing the wave. Keywords: wave transformation, wave height and period, Port of Kuala Tanjung