scholarly journals Assessing the Rate of Shoreline Changes of Rameswaram Island, Tamilnadu, India, using MATLAB Component Runtime Utility & Digital Shoreline Analysis System

The Present study highlights the changes in the coastal tract of Rameswaram island located between the geometric location, latitude 9° 10' to 9° 20' N and the longitude 79° 12' to 79° 30' E. Using Geospatial Technology, Long-term changes have noticed from digitized shorelines taken from Landsat imageries and SOI toposheet for the years 1968, 1978, 1988, 1999, 2009 and 2018. Digital Shoreline Analysis System (DSAS) an extension provided by USGS for ArcGIS used to cast transects perpendicular from the baseline, towards the shorelines. High water Line (HTL) has taken as shoreline in this study. The distance between the shorelines has taken from the cast transects plotted from the baseline. For the rate of change calculation, MATLAB component runtime utility for ArcGIS has used. Based on the Linear Regression Rate (LRR) the shore has classified into High Erosion, Low Erosion, Stable and Low Accretion, High Accretion zones. The island has a shoreline length of 78.4 km, and the studies found that 27.83 km (35.41%) of shoreline is accreting nature, 37.90 km (48.21%) of shoreline is stable, and 12.86 km (16.36 %) of shoreline tends to erode. During the field investigation identified that High amount of erosion occurred in the locations near Pamban, Tharavaithopu and Dhanushkodi. Also, Accretion identified over the locations Ayyanthopu, Natarajapuram and Arichumanai tip. Wind action is one of the physical parameters that induced the erosion in some location of this study area.

2008 ◽  
Vol 39 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Maris Klavins ◽  
Valery Rodinov

The study of changes in river discharge is important for regional climate variability characterization and for development of an efficient water resource management system. The hydrological regime of rivers and their long-term changes in Latvia were investigated. Four major types of river hydrological regimes, which depend on climatic and physicogeographic factors, were characterized. These factors are linked to the changes observed in river discharge. Periodic oscillations of discharge, and low- and high-water flow years are common for the major rivers in Latvia. A main frequency of river discharge regime changes of about 20 and 13 years was estimated for the studied rivers. A significant impact of climate variability on the river discharge regime has been found.


2021 ◽  
Vol 10 (2) ◽  
pp. 299-305
Author(s):  
Yualita Prasida Ramadhani ◽  
Ibnu Praktikto ◽  
Chrisna Adhi Suryono

Wilayah pesisir Kabupaten Demak yang terletak di bagian utara Pantai Jawa merupakan yang rentan terhadap perubahan garis pantai. Perubahan yang serius ini perlu dilakukan pemantauan terus menurus. Penelitian ini dilakukan untuk memperoleh informasi tentang perubahan garis pantai yang disebabkan oleh tingkat abrasi dan akresi yang terjadi di Kecamatan Sayung, Kabupaten Demak pada tahun 2013-2020. Metode penelitian ini dengan menggunakan metode deskriptif studi kasus dengan menggunakan teknologi penginderaan jauh. Metode penginderaan jauh yang digunakan untuk mengetahui perubahan garis pantai adalah dengan metode overlay (tumpang susun) garis pantai pada tahun yang berbeda dan Digital Shoreline Analysis System (DSAS). Hasil penelitian menunjukkan garis pantai Kecamatan Sayung dengan panjang pantai 20.953,59 m, telah mengalami abrasi pantai seluas 141,49 ha dan akresi sebesar 36,61 ha. Sehingga persentase tingkat abrasi sebesar 82% dan akresi sebesar 18%. Secara keseluruhan, rata-rata laju abrasi yang terjadi dalam kurun waktu periode 2013-2020 adalah sebesar 13,08 meter/tahun dan laju akresi sebesar 8,22 meter/tahun. Perubahan garis pantai yang terjadi dari tahun 2013 hingga tahun 2020 lebih banyak mengalami abrasi jika dibandingkan dengan akresi. The coastal area of Demak Regency, which is located on the northern coast of Java, is  vulnerable to shoreline changes. This serious change is necessary for ongoing monitoring. This research was conducted to obtain information about coastline change in coastal Sayung District of Demak Regency in 2013 until 2020. This research method is done by using descriptive method of case study by using remote sensing technology. The remote sensing method used to determine shoreline changes is overlay method and Digital Shoreline Analysis System (DSAS) in different years. Based on the research results can be seen the rate of change of coastline length of 20.953,59 m, shoreline changes that occur in the form of abrasion of 141,49 ha and changes in the form of accretion of 36,61 ha. So that the proportion of the abrasion rate is 82% and the accretion is 18%.Overall, the average rate of abrasion that occurred in the 2013-2020 period was 13.08 meters / year and the accretion rate was 8.22 meters / year. Coastlines that occur from 2013 to 2020 more experienced abrasion process when compared to the accretion process.


1988 ◽  
Vol 5 ◽  
pp. 63-89 ◽  
Author(s):  
Peter Hiscock ◽  
J. Hall

Platypus Rockshelter yielded a rich and varied assemblage of stone artefacts. In this paper we describe temporal change in the artefact assemblage and, by implication, prehistoric technology, concentrating particularly on the evidence for chert stoneworking. Readers are referred to accompanying papers by Hall et al (1988) and Hall and Hiscock (1988) in this volume of QAR for details of the stratigraphy and dating of the site. What is important to reiterate here is that the deposit provides a discontinuous sequence of occupation dating back to approximately 5300 years BP. This, plus the fact the radiocarbon samples were selected to date stratigraphic transition, means that the artefactual sequence is divided into a number of sharply-bounded analytical units, and change can be identified between but not within these units. The necessity for the cultural sequence to be subdivided in this way makes it likely that gradual changes in prehistory will be seen as episodic, and that each unit may be a compilation of a number of discrete occupation events (cf. Frankel 1988). Thus, while we employ strata as minimal units of comparison in the artefactual analysis, we make no assumptions about the uniformity within, and rate of change between, those units. The purpose of the paper is to characterize the long-term changes in the technology of the inhabitants of the site.


2016 ◽  
Vol 27 (1) ◽  
pp. 99-108 ◽  
Author(s):  
Md Ashraful Islam ◽  
Md Shakhawat Hossain ◽  
Tanzeer Hasan ◽  
Sanzida Murshed

A ~65 km coastal stretch has been analyzed to estimate the change dynamics of Kutubdia Island with the help of digital shoreline analysis system (DSAS). This study investigated the reliability of medium resolution satellite imagery for mapping shoreline positions and for estimating historic rates of changes. Nine shoreline positions were extracted on 1972, 1976, 1980, 1989, 1999, 2004, 2009, 2011 and 2014 covering a long term of 42 years period. Rates of shoreline changes were estimated by four statistical methods namely, end point rate (EPR), linear regression rate (LRR), weighted linear regression (WLR) and least median of squares (LMS) by using DSAS and subsequently all the methods were verified with the correlation coefficient (R).The scrutiny of shoreline changes shows that the erosion during the last 42 years has affected the island, with some exception, at the north and west segment where minor accretion has been documented. The average rates of changes estimated for north, south, east and west segment using WLR, LMS, EPR and LRR are Ñ4.0 m/yr, Ñ33.7 m/yr Ñ2.6 m/yr and Ñ5.6 m/yr, respectively. The outcome of this particular analysis might be useful for proper planning and management of Kutubida Island. However, this may also be used in statistical modeling for forecasting the future shoreline position.Bangladesh J. Sci. Res. 27(1): 99-108, June-2014


2021 ◽  
Vol 35 (1) ◽  
pp. 75
Author(s):  
Bernadetta Indri Dwi Astuti ◽  
Agung Laksono ◽  
Dzakwan Taufiq Nur Muhammad ◽  
Intan Fatin Nurbaiti ◽  
Noverita Nur Hanifah ◽  
...  

Abstrak Pemantauan garis pantai akibat adanya proses akresi dan abrasi merupakan salah satu upaya untuk menjaga batas wilayah wilayah di Kabupaten Kendal. Lima multitemporal citra Landsat 7 ETM+ dalam periode tahun 20 tahun (2000-2020) digunakan untuk menganalisis perubahan garis pantai di Kabupaten Kendal.Tujuan dari penelitian ini adalah untuk menganalisis perubahan garis pantai dan menganalisis dampak serta upaya mitigasi dalam menangani perubahan garis pantai di Kabupaten Kendal. Digital Shoreline Analysis System (DSAS) digunakan untuk menganalisis perubahan garis pantai dengan metode Net Shoreline Movement (NSM), End Point Rate (EPR), dan Linear Regression Rate-of-Change (LRR). Hasil penelitian menunjukkan bahwa nilai tertinggi dari Linear Regression Rate-of-Change (LRR) selama periode 20 tahun adalah sebesar 50,9 m/tahun sedangkan nilai terendah sebesar -35,81 meter/tahun. Nilai rata-rata EPR dan NSM selama periode 20 tahun adalah sebesar -0,07 m/tahun dan -1,14 meter. Berdasarkan studi ini, dampak dari perubahan garis pantai yang disebabkan abrasi dan akresi adalah adanya peningkatan dan penurunan luas wilayah. Bentuk mitigasi perubahan garis pantai di Kabupaten Kendal yakni dengan pembangunan breakwater dan penanaman hutan mangrove. Abstract Monitoring shoreline change due to accretion and abrasion processes is one of the efforts to protect the maritime boundary of Kendal Regency. Five multi-temporal Landsat 7 ETM + images spanning 20 years (2000-2020) is used in the tudy for the analysis of shoreline change in Kendal Regency. This study aims to investigate the shoreline change, analyze the impact, and propose mitigation of shoreline change in Kendal Regency as well. Digital Shoreline Analysis System (DSAS) is utilized for the analysis of the shoreline change through Net Shoreline Movement (NSM), End Point Rate (EPR), and Linear Regression Rate-of-Change (LRR). The result shows that the highest value of the Linear Regression Rate (LRR) for 20 years is 50.09 m/year and the lowest value of LRR is -35.81 m/year. The average EPR and NSM are -0.07 m/years and -1.14 m. From this study, it can be observed that the impact of shoreline change induced by accretion and abrasion are the addition and subtraction of the predetermined area. The impacts can be mitigated by building breakwaters and planting mangroves.


Author(s):  
Md. Manjurul Anam ◽  
Abdullah-Al-Jabir ◽  
G. M. Jahid Hasan

Sundarbans, the largest mangrove forest located over the GBM basin, has impacted lives of millions over the years. Standing against various natural disasters, rivers of Sundarbans have undergone major issues such as erosion-accretion of both the banks. The paper deals with a combination of remote sensing and Digital Shoreline Analysis System (DSAS), studying temporal behaviour of bank-lines along the main rivers of Sundarbans for the last three decades. The course of main rivers spanning from southwest Baleswar to west Bengal Bidyadhari within coverage of 10,000 sq. km. has been analyzed in this study. DSAS, the extension tool of ArcGIS, was used for monitoring the rate-of-change from multiple historic bank-line positions extracted from satellite images. Comparison of historic bank-lines between different rivers of Sundarbans was done based on Net Bank-line Movement (NBM) with an interval of five years. Finally, the results were presented graphically to get a better understanding of the bank-line behaviour. The study revealed that the western region of mangrove prevails eroding behaviour than the eastern region. Increased rates of riverward movement due to accretion was found from 2008-2013. These results are important for future monitoring and proper management within the coastal communities surrounding the mangrove forest.


2020 ◽  
Vol 12 (21) ◽  
pp. 9169
Author(s):  
George Lavidas ◽  
John K. Kaldellis

Decarbonisation of any energy system implies that more renewables will have to be incorporated into the grid. This requires a thorough assessment of available resources to properly estimate potential contributions and identify opportunities. This work focuses on the Saronikos Gulf, which is part of the most crowded urban coastline in Greece. Solar, wind and wave resources are analysed, and the long-term characteristics affecting power production are discussed. Solar resources provide ≥250 Wh·m−2 with small long-term changes. Wind resources at coastal and onshore regions are ≥50 W·m−2; however, it has higher annual volatility. Finally, the wave resources of the region are from 130 to 170 W/m with a positive resource rate of change ≈2.5 W·m−1/year. It is expected that multi-generation by different resources, especially with temporal overlaps of wind and waves, will reduce intermittent production, hence accelerating the energy transition.


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