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All Journal Marine Research in Indonesia International Journal of Remote Sensing and Earth Sciences (IJReSES)
Guntur Adhi Rahmawan, Guntur Adhi
Ministry of marine and fishiers
Earth & Planetary Sciences

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PARTICLE SIZE CHARACTERISTICS OF RIVERBED SEDIMENTS TRANSPORTED BY TIDAL BORE ‘BONO’ IN KAMPAR ESTUARY, RIAU-INDONESIA Gemilang, Wisnu Arya; Wisha, Ulung Jantama; Rahmawan, Guntur Adhi
Marine Research in Indonesia Vol 43, No 1 (2018)
Publisher : Research Center for Oceanography - Indonesian Institute of Sciences (LIPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1416.394 KB) | DOI: 10.14203/mri.v43i1.293

Abstract

The presence of tidal bore in the Kampar River (locally known as ‘bono’) may influence sedimentation in the Kampar River and its estuary. Understanding sedimentation mechanisms (e.g., erosion, deposition) is important to communities along the Kampar River, which can be studied by analyzing characteristics of grain size distribution. Here, we study riverbed sediment samples collected from 17 stations using an Ekman grab sampler, accompanied by bathymetry and acoustic Doppler current profiler (ADCP) measurements. Grain size data show that the sediments are coarser upstream and gradually finer downstream. Silty sands are predominant in the upstream section of the river, sands in its river body and sandy silts in the downstream. The results indicate the influence of undular bores on grain size characteristics. We also found that the propagation of bono and Kampar River’s funnelshaped morphology cause intense scouring events of riverbed sediments. Sortation values that range between 0.332.14 suggest unstable currents that result in randomly deposited sediments. The sediment mass transfer per area is positively towards downstream at the low tidal condition. However, after the passage of the bores, the sediment mass transfer area becomes negatively towards upstream.
PARTICLE SIZE CHARACTERISTICS OF RIVERBED SEDIMENTS TRANSPORTED BY TIDAL BORE ‘BONO’ IN KAMPAR ESTUARY, RIAU-INDONESIA Gemilang, Wisnu Arya; Wisha, Ulung Jantama; Rahmawan, Guntur Adhi
Marine Research in Indonesia Vol 43 No 1 (2018)
Publisher : Research Center for Oceanography - Indonesian Institute of Sciences (LIPI)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1416.394 KB) | DOI: 10.14203/mri.v43i1.293

Abstract

The presence of tidal bore in the Kampar River (locally known as ‘bono’) may influence sedimentation in the Kampar River and its estuary. Understanding sedimentation mechanisms (e.g., erosion, deposition) is important to communities along the Kampar River, which can be studied by analyzing characteristics of grain size distribution. Here, we study riverbed sediment samples collected from 17 stations using an Ekman grab sampler, accompanied by bathymetry and acoustic Doppler current profiler (ADCP) measurements. Grain size data show that the sediments are coarser upstream and gradually finer downstream. Silty sands are predominant in the upstream section of the river, sands in its river body and sandy silts in the downstream. The results indicate the influence of undular bores on grain size characteristics. We also found that the propagation of bono and Kampar River’s funnelshaped morphology cause intense scouring events of riverbed sediments. Sortation values that range between 0.332.14 suggest unstable currents that result in randomly deposited sediments. The sediment mass transfer per area is positively towards downstream at the low tidal condition. However, after the passage of the bores, the sediment mass transfer area becomes negatively towards upstream.
TENDENCY FOR CLIMATE-VARIABILITY-DRIVEN RISE IN SEA LEVEL DETECTED IN THE ALTIMETER ERA IN THE MARINE WATERS OF ACEH, INDONESIA Rahmawan, Guntur adhi; wisha, ulung jantama
International Journal of Remote Sensing and Earth Sciences (IJReSES) Vol 16, No 2 (2019)
Publisher : National Institute of Aeronautics and Space of Indonesia (LAPAN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (778.66 KB) | DOI: 10.30536/j.ijreses.2019.v16.a3091

Abstract

Long-term sea level rise (SLR) leads to increasing frequency in overtopping events resulting from polar ice liquefaction triggered by rising global temperatures. Aceh province is directly bordered by the Indian Ocean, and is subject to the influence of ocean–atmosphere interactions which have a role in triggering temperature and sea level anomalies. Elevated sea level is possibly caused by temperature-induced water mass redistributions. This study aimed to prove that the Indian Ocean Dipole (IOD) and El-Nino–Southern Oscillation (ENSO) had an influence on sea level change in Aceh waters over the six years 2009–2015. Sea level anomaly (SLA) was identified using Jason-2 satellite data for the 2009–2015 period, to enable the mathematical prediction of SLR rate for further years. We found that SLR was approximately 0.0095 mm/year with an upward trend during the six years of observation. Overall, negative mode of IOD and positive phase of ENSO tend to trigger anomalies of sea level at certain times, and have a stronger influence on increasing SLA and sea surface temperature anomaly (SSTA) which takes place in a ‘see-saw’ fashion. Over the period of observation, the strongest evidence of IOD-correlated SLA, ENSO-correlated SLA and SSTA-correlated SLA were identified in second transitional seasons, with more than 50% of R2 value. The upward trend in SLA is influenced by climatic factors that successively control ocean–atmosphere interactions in Aceh’s marine waters. 
Co-Authors Ulung Jantama Wisha Wisnu Arya Gemilang, Wisnu Arya