1,720,983 research outputs found
Dämpfung von Solitären Wellen und Seegang durch Küstenwälder
Full text linkBased on available knowledge and the field evidence from the latest extreme wave events, the interaction of coastal forests and tsunami as well as storm waves still needs further study directed towards an improved understanding of the attenuation performance of coastal forests and the development of reliable prediction models. The objective is to improve the understanding of the physical processes associated with the energy attenuation of tsunami and storm waves through coastal forests by developing a generic methodology for the parameterization of 3-D complex typical coastal forest vegetations and by performing physical laboratory experiment and numerical modelling. To achieve this objective, two typical coastal forest vegetations (mangroves and coastal pines) representing two different coastal habitats were selected. A physically-based parameterization using easily quantifiable parameters of the real tree was carried out and tested in a current flume for both stiff and flexible structure assumptions. Following the parameterization stage, large scale model tests with different model setups and wave conditions (solitary waves representing tsunami and regular/irregular waves representing storm waves) were simultaneously performed in the Twin Wave Flume of Leichtweiß-Instituts (LWI) to investigate the hydraulic performance and the hydraulic resistance characteristics of the coastal forest models. Furthermore, an empirical relationship (forest width factor) and a new procedure to assess tsunami attenuation by coastal forests have also been succesfully developed based on numerical simulation using the nonlinear shallow water equation model with hydraulic resistant coefficients obtained from the laboratory experiments. It can, therefore, be used as a practical tool in coastal zone management to evaluate feasible measures in mitigating and managing risks associated with tsunami and storm waves, particularly in the regions where coastal forests are favourable.Aus vielen Berichten nach dem Tsunami 2004 wurde die Schutzwirkung der Küstenwälder mehrfach bestätigt, obwohl bislang die Dämpfungsprozesse weitgehend unbekannt waren und hierfür kein verlässlicher Nachweis durch prozessbasierte Modelle vorlag. Vor diesem Hintergrund und dem Hintergrund des Wissensstandes besteht das Hauptziel dieser Studie darin, das Verständnis der Prozesse substantiell zu verbessern, die für die Dämpfung von Tsunami/Windwellen durch Küstenwälder verantwortlich sind. Den Schwerpunkt der Arbeit bilden die Entwicklung und systematische experimentelle Verifizierung eines neuen prozess-basierten Verfahrens zur Parametrisierung steifer und flexibler Walvegetation hinsichtlich des Strömungswiderstands. Mit den anhand dieses neuen Verfahrens ermittelten parametrisierten Modellbäumen wurden systematische Untersuchungen über die Dämpfungswirkung der o.g. zwei Waldtypen in den beiden Wellenkanälen des Leichtweiß-Instituts durchgeführt. Tsunami-ähnlichen solitären Wellen sowie regelmäßigem und unregelmäßigem Seegang wurden generiert. Berücksichtigt wurden sowohl globale Prozesse (hydraulische Wirksamkeit) als auch lokale Prozesse (z.B. Strömungswiderstand). Hinsichtlich der numerischen Modellierung wurde das nichtlineare Flachwasserwellen-Modell mit den aus den Experimenten gewonnenen Strömungswiderstandskoeffizienten implementiert und Daten erfolgreich validiert. Das validierte Modell wurde zur Durchführung einer systematischen Parameterstudie eingesetzt, die in die Entwicklung einer neuen Formel zur praktischen Ermittlung der hydraulischen Wirksamkeit von Küstenwäldern als Funktion eines dimensionslosen Parameters resultierte. Dieser Parameter fasst sinnvollerweise die Einflüsse der Breite und Dichte des Küstenwaldes sowie der Wellenhöhe und Wassertiefe am Vorlandfuß zusammen. Darüber hinaus wurden Empfehlungen für die praktische Bewertung der hydraulischen Wirksamkeit von Küstenwäldern zur Risikoreduzierung bei Tsunami und Sturmfluten ausgearbeitet
2D multichannel seismic reflection raw data (entire dataset) of RV SONNE during cruise SO299/2
No full textThe raw 2D multichannel seismic reflection data in this project were acquired during expedition SO299/2 offshore Krakatau using a single GI Gun. The data were recorded with a 48-channel streamer. The Krakatau survey aimed to shed light on the erupted volumes of the disastrous 1883 eruption and decipher the processes leading to a damaging tsunami. The data comprise 381 line kilometers and are provided in raw format (SEG-D) and associated standardized metadata. Detailed information on the acquisition can be found in the SO299/2 cruise report (https://doi.org/10.48433/cr_so299_2). In addition, a technical report is provided with this data set
Perubahan Garis Pantai di Pesisir Cirebon Berdasarkan Analisis Spasial
Full text linkABSTRAKInformasi kerusakan daerah Pesisir Utara Jawa bukan hal yang baru. Daerah pesisir Cirebon sebagai salah satu bagian Pesisir Utara Jawa mengalami permasalahan dinamika pesisir yang ditandai oleh erosi dan sedimentasi pantai. Erosi dan sedimentasi merupakan permasalahan mendasar dalam pengelolaan wilayah pesisir. Penelitian ini mengkaji kerusakan pesisir Cirebon ditinjau melalui perubahan garis pantai yang ditimbulkan oleh proses sedimentasi dan erosi yang terjadi secara alami ataupun akibat aktivitas manusia. Pengolahan data satelit Landsat tahun 1999 dan 2013 memberikan informasi sedimentasi dan erosi di sekitar pesisir Cirebon. Hasil perubahan garis pantai dari analisis satelit diverifikasi dengan pengamatan di lapangan dan wawancara dengan masyarakat pesisir yang dilakukan pada Juni 2013. Analisis memperlihatkan perubahan garis pantai di Pesisir Cirebon sangat dipengaruhi oleh aspek-aspek hidro-oseanografi, morfologi pantai, dan aktivitas manusia. Hasil ini diharapkan dapat menambah informasi mengenai kondisi pesisir di Cirebon yang dapat digunakan dasar dalam pengelolaan kerusakan wilayah pesisir sesuai dengan kondisi real di lapangan.Kata kunci: Cirebon, garis pantai, erosi, akresi, panturaABSTRACTThe damage of coastal area in Northen Java has been known for decades. As part of Northen Java Coastal, Cirebon coastal area suffered from severe damage due to erosion-abrasion phenomenon and turned to be a fundamental problem in coastal area management. This research analyses Cirebon coastal changes by analising shoreline changes induced by long term sedimentation and erosion processes. Landsat data in 1999 and 2013 are used in shoreline change analysis. The sattelite analysis results are verified by field observations and coastal communities interview in June 2013. The results show that the coastline dynamics of Cirebon are strongly influenced by hydro-oceanography aspects, coastal morphology and human activities. This result provides valuable information on the latest conditions of coastal area in Cirebon and this can be used as basis for land use management and future mitigation of costal areas.Keywords: Cirebon, coastlines, erosion, accretion, pantur
THE MODELLING OF SUSPENDED SEDIMENT DISTRIBUTION DUE TO TIN MINING IN BANGKA SEAS
Full text linkPulau Bangka merupakan penambangan timah lepas pantai terbesar di Indonesia yang dilakukan oleh perusahan dan masyarakat, baik legal maupun ilegal. Hal ini menjadi mengkhawatirkan terutama akan dampaknya terhadap peningkatan sedimentasi, seperti wilayah Teluk Kelabat yang direncanakan menjadi kawasan konservasi. Tujuan penelitian ini adalah mengetahui kondisi hidro-oseanografi dan sebaran Total Suspended Solid (TSS) akibat penambangan timah di perairan Bangka terutama di Teluk Kelabat. Metode yang digunakan adalah analisis pemodelan numerik dengan menggunakan software MIKE21 untuk memperoleh data hidro-oseanografi dan model sebaran TSS dengan sumber TSS dari tiap-tiap lokasi Izin Usaha Pertambangan (IUP) melalui modul Flow Model Flexibel Mesh (FM) dan Mud Transport (MT). Verifikasi hasil model diperoleh korelasi sebesar 0,9435 dengan Root Mean Squared Error (RMSE) sebesar 0,1611 untuk pasang-surut. Tailing penambangan timah lepas pantai akan menyebabkan tingginya sebaran TSS di perairan Bangka, terutama aktivitas penambangan di perairan yang dangkal (<10 m) dan dekat pesisir (<2 mil). Sebaran TSS di perairan Bangka akan dominan terbawa ke arah Selat Bangka. Pada Teluk Kelabat, TSS bernilai sekitar 0-25 mg/L dan menyebar ke seluruh wilayah yang dapat mencapai radius sekitar 16 mil. Hasil penelitian ini diharapkan dapat menjadi rekomendasi bagi stakeholder seperti penyusunan Rencana Zonasi Pesisir Dan Pulau-Pulau Kecil (RZWP3K) di Bangka Belitung.Bangka Island is the largest offshore tin mining in Indonesia conducted by companies and local communities, both legal and illegal. This could be alarming, for example Kelabat Bay which planned as a conservation area due to the impact of increase of suspended solid. This research aims to analyze the hydro-oceanographic conditions and Total Suspended Solid (TSS) distribution process due to tin mining in Bangka Waters, especially in Kelabat Bay. The method used was numerical modelling using MIKE 21 software to obtain hydro-dynamics data and TSS distribution due its sources from each mining spot with Flow Model Flexibel Mesh (FM) module and Mud Transport (MT) module. The model’s verification obtained 0.9435 correlation and 0.1611 Root Mean Squared Error (RMSE) for tidal data. The tailing will cause high TSS distribution in Bangka Waters especially for mining activities in shallow waters (<10 m) and nearby coast (<2 miles). The distribution of TSS in Bangka Waters will be dominantly carried towards the Bangka Strait. In Kelabat Bay itself, the TSS value is 0-25 mg/L and spread throughout the region with radius around 16 miles. The Bangka Waters, especially Kelabat Bay which planned as conservation area will be threatened by the increase of TSS due to offshore mining activities. It will become the recommendation for policy making in Bangka Belitung such as coastal and small islands zoning policy
Conditions of Kejawanan Beach Based on Standard Quality and Suitability for Pollution Index Marine Tourism Area
Full text linkKejawanan tourist beach is one beach which is located in West Java. This beach is located side to the Kejawanan fishing port. Kejawanan beach topography sloping beach with quiet waters and the waves are not too big. The dominant wind direction throughout the year that influencet the formation of ocean waves are heading toward the bay coast of Cirebon. The existence tourist beach that is located near to the fishing port crowded with activity interesting to known the conditions coast as marine tourism area based on Water quality standars according to Decree of The Minister of Environment Number 51 of 2004. Pollution indeks is based on Decree of The Minister of Environment Number 115 of 2003. Indication of biological contamination by Diversity index of makrobentic animal. The results of the research obtained Water quality standard for marine tourism area mostly exceeded. Pollution index is at the level Heavy pollution. Diversity index of macrobentic animal are at the level of Medium Pollution. Keywords : Kejawanan, standard quality, pollution index, diversity index Â
POLA SEBARAN KUALITAS AIR BERDASARKAN KESESUAIAN BAKU MUTU UNTUK BIOTA LAUT DI TELUK KENDARI PROVINSI SULAWESI TENGGARA
Full text linkKondisi perairan Teluk Kendari saat ini semakin memprihatinkan, padahal kawasan perairan ini merupakan pelabuhan utama di Provinsi Sulawesi Tenggara. Daerah Aliran Sungai (DAS) Wanggu seluas 339,73 km² merupakan DAS penyumbang sedimen terbesar di perairan Teluk Kendari, dengan laju sedimentasi yang semakin meningkat. Kondisi iniakan menyebabkan terjadinya ancaman terhadap kualitas air untuk biota laut dan lingkungan sekitarnya. Penelitian ini bertujuan menganalisis pola sebaran kualitas air laut berdasarkan KepMen LH No.51 Tahun 2004 tentang baku mutu untuk biota laut. Penelitian dilaksanakan pada bulan Juni 2015 berdasarkan parameter nilai pH, DO, kekeruhan dan salinitas yang diukur menggunakan alat Water Quality Checker TOA DKK di 25 stasiun titik pengamatan. Data – data yang diperoleh kemudian disesuaikan dengan baku mutu air untuk biota laut dan selanjutnya dilakukan analisis dengan pendekatan spasial menggunakan Sistem Informasi Geografis (SIG). Hasil yang diperoleh menunjukan nilai pH berkisar antara 8,64 – 8,96 ini berarti kondisi pH berada pada kondisi tidak sesuai untuk biota laut, nilai DO berkisar antara 6,57 – 7,29 mg/l ini berarti kondisi DO berada pada kondisi sesuai untuk biota laut, sedangkan nilai salinitas berkisar antara 11,2-33,5% ini berarti pada stasiun 3, 24 dan 25 berada pada kondisi sesuai untuk biota laut dannilai kekeruhan berkisar 1,8 – 64,4 ntu, ini berarti nilai kekeruhan pada stasiun 8, 10, 11, dan 22 berada pada kondisi sesuai untuk biota laut.KATA KUNCI: Biota laut, kualitas air laut, Teluk Kendari
IMPACTS OF MARINE SAND MINING ACTIVITIES TO THE COMMUNITY OF LONTAR VILLAGE, SERANG - BANTEN
Full text linkMarine sand mining activities in Lontar Village have been started legally since 2003 and temporarily halted in 2013. The locals blamed the activities for severe environmental destruction in almost every corner of the village such as low productivity ofaquaculture, coastal erosion, and habitat loss. This paper has an objective to provide preliminary data and analyses for environmental impact assessment of marine sand mining in Serang (Lontar Village). Field investigations were carried out in June 2014 to collect primary data such as bathymetrical data and water quality parameters in the region to understand the environmental conditions after 10 years of marine sand mining activities as well as the characteristicsof local oceanography. Extensive interview with the locals were also conducted to collect information about the socio-economic conditions of the village. Field findings showed that LontarVillage have experienced critical environmental problems such as coastal erosion, high turbidiy and loss of marine lives. Moreover, we also found that the abandoned aquaculture fields have also been converted as sand mining quarries. Recommendations to reduce further environmental damage in Lontar Village are proposed considering both socio-economy and physical aspects.
Keywords:sand mining, Lontar village, environmental damage, erosion
Aktifitas penambangan pasir laut di Kampung Lontar telah dimulai secara legal sejak 2003 dan telah berhenti untuk sementara tahun 2013. Keberatan penduduk setempat terhadap aktifitas penambangan tersebut adalah disebabkan oleh adanya gangguan lingkungan di hampir setiap sudut perkampungan seperti rendahnya produktifitas budidaya perikanan, erosi pantai dan hilangnya. berbagai aneka ragam habitat. Tujuan penelitian ini adalah untuk mendapatkan data awal dan analisis terhadap pengaruh lingkungan akibat aktifitas penambangan pasir laut. Penyelidikan lapangan telah dilaksanakan pada bulan Juni 2014 yaitu untuk mengumpukan data sekunder seperti batimetri dan parameter kualitas air di kawasan tersebut. Penelitian ini adalah untuk mengeahui kondisi lingkungan setelah 10 tahun aktifitas penambangan pasir laut, begitu juga karakteristik oseanografi daerah tersebut. Wawancara intensif dengan penduduk lokal telah dilakukan juga untuk mengumpulkan informasi tentang kondisi sosial ekonomi perkampungan tersebut. Temuan lapangan menunjukkan bahwa perkampungan Lontar mengalami masalah lingkungan yang kritis seperti proses erosi pantai, kekeruhan yang tinggi, dan hilangnya kehidupan laut. Lebih lanjut lagi penelitian ini telah menemukan bahwa sekumpulan ladang budidaya perairan telah beralih menjadi tambang pasir. Saran untuk memperkecil kerusakan lingkungan lebih jauh di Perkampungan Lontar, diusulkan pertimbangan aspek sosial ekonomi dan aspek fisik.
Kata kunci : tambang pasir, Perkampungan Lontar, kerusakan lingkungan, erosi
Anak Krakatau volcano emergency tsunami early warning system
No full textOn 22 Dec 2018 13:56 UTC a Tsunami was generated from the area of the Anak Krakatau Volcano, with waves propagating in all directions inside the Sunda Strait, the sea portion between the Java and Sumatra islands. The cause of this event seems to have a correlation with the ongoing Volcanic eruption, which was particularly active since June 2018 [4],
At the time of the event, the Tsunami Early Warning System currently implemented in Indonesia, could not be used because there was no mechanism to activate the system on the basis of measurement of sea levels or other information from the volcano activities. Given the situation, the Indonesian Authorities have decided to implement an Emergency Early Warning system that can timely inform if any sea level disturbance could represent a Tsunami from the volcano activities and therefore give the possibility to activate the sirens.
The Joint Research Centre (JRC), in collaboration with the Indonesian Tsunami Society, the Marine Research Centre of the Ministry of Marine Affairs and Fisheries and the Meteorological, Climatological and Geophysical Agency of Indonesia (BMKG) worked together since the event in December in order to design and implement the new Emergency System. The new system will adopt the real time fast Tsunami instruments (Inexpensive Device for Sea Level Monitoring or IDSL), developed by JRC [ 1], to monitor in real time on a 24/7 the sea level to provide email, SMS alerts, CCTV images and inform about a potential event. The activation of the sirens in the area can be performed after a human verification of the signals. The first 2 devices have been installed at the end of January 2018; other devices will be provided and installed in the near future.JRC.E.1 - Disaster Risk Managemen
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
