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Conventional calibration methods adopted in hydrological modelling are based on streamflow data measured at certain river sections. However, streamflow measurements are usually sparse and, in such instances, remote-sensing-based products may be used as an additional dataset(s) in hydrological model calibration. This study compares two main calibration approaches: (a) single variable calibration with streamflow and evapotranspiration separately, and (b) multi-variable calibration with both variables together. Here, we used remote sensing-based evapotranspiration data from Global Land Evaporation: the Amsterdam Model (GLEAM ET), and measured streamflow at four stations to calibrate a Soil and Water Assessment Tool (SWAT) and evaluate the performances for Chindwin Basin, Myanmar. Our results showed that when one variable (either streamflow or evapotranspiration) is used for calibration, it led to good performance with respect to the calibration variable but resulted in reduced performance in the other variable. In the multi-variable calibration using both streamflow and evapotranspiration, reasonable results were obtained for both variables. For example, at the basin outlet, the best NSEs (Nash-Sutcliffe Efficiencies) of streamflow and evapotranspiration on monthly time series are, respectively, 0.98 and 0.59 in the calibration with streamflow alone, and 0.69 and 0.73 in the calibration with evapotranspiration alone. Whereas, in the multi-variable calibration, the NSEs at the basin outlet are 0.97 and 0.64 for streamflow and evapotranspiration, respectively. The results suggest that the GLEAM ET data, together with streamflow data, can be used for model calibration in the study region as the simulation results show reasonable performance for streamflow with an NSE > 0.85. Results also show that many different sets of parameter values (‘good parameter sets’) can produce results comparable to the best parameter set.
T. Sirisena; Shreedhar Maskey; Roshanka Ranasinghe. Hydrological Model Calibration with Streamflow and Remote Sensing Based Evapotranspiration Data in a Data Poor Basin. Remote Sensing 2020, 12, 3768 .
AMA StyleT. Sirisena, Shreedhar Maskey, Roshanka Ranasinghe. Hydrological Model Calibration with Streamflow and Remote Sensing Based Evapotranspiration Data in a Data Poor Basin. Remote Sensing. 2020; 12 (22):3768.
Chicago/Turabian StyleT. Sirisena; Shreedhar Maskey; Roshanka Ranasinghe. 2020. "Hydrological Model Calibration with Streamflow and Remote Sensing Based Evapotranspiration Data in a Data Poor Basin." Remote Sensing 12, no. 22: 3768.
This study demonstrates how a large-scale satellite-derived dataset can be used to investigate statistically robust trends in shoreline position over a 31-year period from 1987 to 2017, at a regional scale. Regional patterns of shoreline behaviour are important for resolving consistent or, alternatively, dissimilar patterns of past shoreline change. Such patterns are best explored using temporally frequent and spatially extensive datasets. Here we analyse satellite-derived shorelines to identify spatial patterns of hotspots of coastline change on the wave-exposed coast of Victoria in south-east Australia where rates of change exceed 0.5 m yr−1. Analysis of shoreline position changes at a 50 m alongshore interval along 900 km of the 1230 km coastline reveals a number of distinct behaviours related to coastal type (rock vs sand coast), landform, shoreline orientation and/or anthropogenic drivers of change. Overall the results show that statistically significant change in shoreline position has affected only a relatively small proportion of the study region over the last 31 years; that the proportion and rate of progradational and recessional change is similar; and that change is localised but dispersed widely along the Victorian coast. Coasts located at the entrances to large tidal inlets have shown the greatest change. The association of hotspots with embayed sandy beaches and adjacent to headlands points to the importance of geological control on the shoreline behaviour. Consistent with other regional scale studies of shoreline change, this study found little regional coherence in shoreline behaviour. Instead change is predominately attributed to local factors such as the geological framework of the coast, localised hydrodynamic conditions and anthropogenic influences. Collectively, these results indicate that there is strong geologic control on shoreline erosion in Victoria due to the high diversity of landforms along the coastline; and that further analysis is required to tease out the seasonal to interannual sensitivities to changes in the historical wave climate and the secondary interaction of sediment supply for headlands and hydrodynamics for tidal inlets.
Teresa M. Konlechner; David M. Kennedy; Julian J. O'Grady; Chloe Leach; Roshanka Ranasinghe; Rafael C. Carvalho; Arjen P. Luijendijk; Kathleen L. McInnes; Daniel Ierodiaconou. Mapping spatial variability in shoreline change hotspots from satellite data; a case study in southeast Australia. Estuarine, Coastal and Shelf Science 2020, 246, 107018 .
AMA StyleTeresa M. Konlechner, David M. Kennedy, Julian J. O'Grady, Chloe Leach, Roshanka Ranasinghe, Rafael C. Carvalho, Arjen P. Luijendijk, Kathleen L. McInnes, Daniel Ierodiaconou. Mapping spatial variability in shoreline change hotspots from satellite data; a case study in southeast Australia. Estuarine, Coastal and Shelf Science. 2020; 246 ():107018.
Chicago/Turabian StyleTeresa M. Konlechner; David M. Kennedy; Julian J. O'Grady; Chloe Leach; Roshanka Ranasinghe; Rafael C. Carvalho; Arjen P. Luijendijk; Kathleen L. McInnes; Daniel Ierodiaconou. 2020. "Mapping spatial variability in shoreline change hotspots from satellite data; a case study in southeast Australia." Estuarine, Coastal and Shelf Science 246, no. : 107018.
We describe an innovative approach to estimate global changes in extreme wave conditions by 2100, as a result of projected climate change. We generate a synthetic dataset from an ensemble of wave models forced by independent climate simulation winds, enhancing statistical confidence associated with projected changes in extreme wave conditions. Under two IPCC representative greenhouse gas emission scenarios (RCP4.5 and RCP8.5), we find that the magnitude of a 1 in 100-year significant wave height (Hs) event increases by 5 to 15% over the Southern Ocean by the end of the 21st century, compared to the 1979–2005 period. The North Atlantic shows a decrease at low to mid latitudes (≈5 to 15%) and an increase at high latitudes (≈10%). The extreme significant wave height in the North Pacific increases at high latitudes by 5 to 10%. The ensemble approach used here allows statistical confidence in projected changes of extremes.
Alberto Meucci; Ian R. Young; Mark Hemer; Ebru Kirezci; Roshanka Ranasinghe. Projected 21st century changes in extreme wind-wave events. Science Advances 2020, 6, eaaz7295 .
AMA StyleAlberto Meucci, Ian R. Young, Mark Hemer, Ebru Kirezci, Roshanka Ranasinghe. Projected 21st century changes in extreme wind-wave events. Science Advances. 2020; 6 (24):eaaz7295.
Chicago/Turabian StyleAlberto Meucci; Ian R. Young; Mark Hemer; Ebru Kirezci; Roshanka Ranasinghe. 2020. "Projected 21st century changes in extreme wind-wave events." Science Advances 6, no. 24: eaaz7295.
The combination of climate change impacts, declining fluvial sediment supply, and heavy human utilization of the coastal zone, arguably the most populated and developed land zone in the world, will very likely lead to massive socio-economic and environmental losses in the coming decades. Effective coastal planning/management strategies that can help circumvent such losses require reliable local scale (<~10 km) projections of coastal change resulting from the integrated effect of climate change driven variations in mean sea level, storm surge, waves, and riverflows. Presently available numerical models are unable to adequately fulfill this need. A new generation of multi-scale, probabilistic coastal change models is urgently needed to comprehensively assess and optimise coastal risk at local scale, enabling risk informed, climate proof adaptation measures that strike a good balance between risk and reward.
Roshanka Ranasinghe. On the need for a new generation of coastal change models for the 21st century. Scientific Reports 2020, 10, 1 -6.
AMA StyleRoshanka Ranasinghe. On the need for a new generation of coastal change models for the 21st century. Scientific Reports. 2020; 10 (1):1-6.
Chicago/Turabian StyleRoshanka Ranasinghe. 2020. "On the need for a new generation of coastal change models for the 21st century." Scientific Reports 10, no. 1: 1-6.
The world’s large rivers are under stress and experiencing unprecedented changes in hydrology, ecosystems, and fluvial sediment loads. Many of these rivers terminate at the great deltas of the world (home to 500 million people), which depend on fluvial sediments for their very existence. While fluvial sediment loads of large rivers have already been greatly modified by human activities, climate change is expected to further exacerbate the situation. But how does the effect of climate change on fluvial sediment loads compare with that of human impacts? Here, we address this question by combining historical observations and 21st century projections for one of the world’s largest 25 rivers containing two mega dams; Pearl River, China. Our analysis shows that variations in fluvial sediment supply to the coast from the Pearl river over a ~150 year study period are dominated by human activities. Projected climate change driven 21st century increases in riverflow will only compensate for about 1% of the human induced deficit in sediment load, leading to the coastal zone being starved of about 6000 Mt of sediment over the remainder of this century. A similar dominance of human impacts on fluvial sediment supply is likely at other heavily engineered rivers.
Roshanka Ranasinghe; Chuang Shou Wu; John Conallin; Trang Minh Duong; Edward Jamal Anthony. Disentangling the relative impacts of climate change and human activities on fluvial sediment supply to the coast by the world’s large rivers: Pearl River Basin, China. Scientific Reports 2019, 9, 1 -10.
AMA StyleRoshanka Ranasinghe, Chuang Shou Wu, John Conallin, Trang Minh Duong, Edward Jamal Anthony. Disentangling the relative impacts of climate change and human activities on fluvial sediment supply to the coast by the world’s large rivers: Pearl River Basin, China. Scientific Reports. 2019; 9 (1):1-10.
Chicago/Turabian StyleRoshanka Ranasinghe; Chuang Shou Wu; John Conallin; Trang Minh Duong; Edward Jamal Anthony. 2019. "Disentangling the relative impacts of climate change and human activities on fluvial sediment supply to the coast by the world’s large rivers: Pearl River Basin, China." Scientific Reports 9, no. 1: 1-10.
Thirty one percent (31%) of the world’s coastline consists of sandy beaches and dunes that form a natural defense protecting the hinterland from flooding. A common measure to mitigate erosion along sandy beaches is the implementation of sand nourishments. The design and acceptance of such a mitigating measure require information on the expected evolution at time scales from storms to decades. Process-based morphodynamic models are increasingly applied, together with morphodynamic acceleration techniques, to obtain detailed information on this wide scale of ranges. This study shows that techniques for the acceleration of the morphological evolution can have a significant impact on the simulated evolution and dispersion of sandy interventions. A calibrated Delft3D model of the Sand Engine mega-nourishment is applied to compare different acceleration techniques, focusing on accuracy and computational times. Results show that acceleration techniques using representative (schematized) wave conditions are not capable of accurately reproducing the morphological response in the first two years. The best reproduction of the morphological behavior of the first five years is obtained by the brute force simulations. Applying input filtering and a compression factor provides similar accuracy yet with a factor five gain in computational cost. An attractive method for the medium to long time scales, which further reduces computational costs, is a method that uses representative wave conditions based on gross longshore transports, while showing similar results as the benchmark simulation. Erosional behavior is captured well in all considered techniques with variations in volumes of about 1 million m 3 after three decades. The spatio-temporal variability of the predicted alongshore and cross-shore distribution of the morphological evolution however have a strong dependency on the selected acceleration technique. A new technique, called ’brute force merged’, which incorporates the full variability of the wave climate, provides the optimal combination of phenomenological accuracy and computational efficiency (a factor of 20 faster than the benchmark brute force technique) at both the short and medium to long time scales. This approach, which combines realistic time series and the mormerge technique, provides an attractive and flexible method to efficiently predict the evolution of complex sandy interventions at time scales from hours to decades.
Arjen P. Luijendijk; Matthieu A. De Schipper; Roshanka Ranasinghe. Morphodynamic Acceleration Techniques for Multi-Timescale Predictions of Complex Sandy Interventions. Journal of Marine Science and Engineering 2019, 7, 78 .
AMA StyleArjen P. Luijendijk, Matthieu A. De Schipper, Roshanka Ranasinghe. Morphodynamic Acceleration Techniques for Multi-Timescale Predictions of Complex Sandy Interventions. Journal of Marine Science and Engineering. 2019; 7 (3):78.
Chicago/Turabian StyleArjen P. Luijendijk; Matthieu A. De Schipper; Roshanka Ranasinghe. 2019. "Morphodynamic Acceleration Techniques for Multi-Timescale Predictions of Complex Sandy Interventions." Journal of Marine Science and Engineering 7, no. 3: 78.
Sandy shorelines are constantly evolving, threatening frequently human assets such as buildings or transport infrastructure. In these environments, sea-level rise will exacerbate coastal erosion to an amount which remains uncertain. Sandy shoreline change projections inherit the uncertainties of future mean sea-level changes, of vertical ground motions, and of other natural and anthropogenic processes affecting shoreline change variability and trends. Furthermore, the erosive impact of sea-level rise itself can be quantified using two fundamentally different models. Here, we show that this latter source of uncertainty, which has been little quantified so far, can account for 20 to 40% of the variance of shoreline projections by 2100 and beyond. This is demonstrated for four contrasting sandy beaches that are relatively unaffected by human interventions in southwestern France, where a variance-based global sensitivity analysis of shoreline projection uncertainties can be performed owing to previous observations of beach profile and shoreline changes. This means that sustained coastal observations and efforts to develop sea-level rise impact models are needed to understand and eventually reduce uncertainties of shoreline change projections, in order to ultimately support coastal land-use planning and adaptation.
Gonéri Le Cozannet; Thomas Bulteau; Bruno Castelle; Roshanka Ranasinghe; Guy Wöppelmann; Jeremy Rohmer; Nicolas Bernon; Deborah Idier; Jessie Louisor; David Salas-Y-Mélia. Quantifying uncertainties of sandy shoreline change projections as sea level rises. Scientific Reports 2019, 9, 1 -11.
AMA StyleGonéri Le Cozannet, Thomas Bulteau, Bruno Castelle, Roshanka Ranasinghe, Guy Wöppelmann, Jeremy Rohmer, Nicolas Bernon, Deborah Idier, Jessie Louisor, David Salas-Y-Mélia. Quantifying uncertainties of sandy shoreline change projections as sea level rises. Scientific Reports. 2019; 9 (1):1-11.
Chicago/Turabian StyleGonéri Le Cozannet; Thomas Bulteau; Bruno Castelle; Roshanka Ranasinghe; Guy Wöppelmann; Jeremy Rohmer; Nicolas Bernon; Deborah Idier; Jessie Louisor; David Salas-Y-Mélia. 2019. "Quantifying uncertainties of sandy shoreline change projections as sea level rises." Scientific Reports 9, no. 1: 1-11.
Climate change is globally recognized as one of the key drivers of degradation of coastal wetland ecosystems, causing considerable alteration of services provided by these habitats. Quantifying the physical impacts of climate change on these services is therefore of utmost importance. Yet, practical work in this field is fragmented and scarce in current literature, especially in developing countries which are likely to suffer most from the adverse climate change impacts. Using a coherent scenario-based approach that combines assessment of physical impacts with economic valuation techniques, here we quantify potential climate change driven losses in the value of wetland ecosystems services due to relative sea-level rise (RSLR)-induced inundation in the vulnerable Western coastal area of Bangladesh in 2100. The results show a small inundation area in 2100 under the three IPCC climate scenarios of RCP2.6 (with 0.25 m of RSLR), RCP6.0 (with 1.18 m of RSLR), and RCP8.5 (with 1.77 m of RSLR) for the coastal wetland ecosystems including the Sundarbans mangrove forest, neritic system and aquaculture ponds. In all scenarios, RSLR will drive a loss in the total value of ecosystem services such as provision of raw materials, and food provision, ranging from US$ 0–1 million to US$ 16.5–20 million, respectively. The outcomes of this study reveal that RSLR-induced inundation on its own, is unlikely to be a major threat to the wetland ecosystems in Western coast of Bangladesh. This would suggest that other climate change impacts such as coastal erosion, increase in frequency of cyclone events, and sea temperature rise might be the likely primary drivers of change in the value of wetland ecosystems services in this area.
Seyedabdolhossein Mehvar; Tatiana Filatova; Motaleb Hossain Sarker; Ali Dastgheib; Roshanka Ranasinghe. Climate change-driven losses in ecosystem services of coastal wetlands: A case study in the West coast of Bangladesh. Ocean & Coastal Management 2019, 169, 273 -283.
AMA StyleSeyedabdolhossein Mehvar, Tatiana Filatova, Motaleb Hossain Sarker, Ali Dastgheib, Roshanka Ranasinghe. Climate change-driven losses in ecosystem services of coastal wetlands: A case study in the West coast of Bangladesh. Ocean & Coastal Management. 2019; 169 ():273-283.
Chicago/Turabian StyleSeyedabdolhossein Mehvar; Tatiana Filatova; Motaleb Hossain Sarker; Ali Dastgheib; Roshanka Ranasinghe. 2019. "Climate change-driven losses in ecosystem services of coastal wetlands: A case study in the West coast of Bangladesh." Ocean & Coastal Management 169, no. : 273-283.
Nearshore sandbar patterns can affect the hydrodynamics and, as a result, the beach morphodynamics in the nearshore zone. Hence, spatial and temporal variability in the sandbars can influence beach accretion and erosion. Understanding the variability of the sandbar system can therefore be crucial for informed coastal zone management. So far, the methods to study sandbar dynamics mainly include datasets of video observations or occasional bathymetric surveys. However, at most locations around the world, these types of data are not or only scarcely available. In this paper we present an alternative method to analyze long-term sandbar variability by means of freely available satellite imagery. These images are globally available since the 1980’s and, thus, have the potential to be applicable at any location in the world. Here, we will illustrate the methodology by means of a case study at Anmok beach at the South Korean East coast.
Panagiotis Athanasiou; Wiebe De Boer; Pieter Koen Tonnon; Jeseon Yoo; Matthieu De Schipper; Sierd De Vries; Roshanka Ranasinghe; Ad Reniers. LONG-TERM BAR DYNAMICS USING SATELLITE IMAGERY: A CASE STUDY AT ANMOK BEACH, SOUTH KOREA. Coastal Engineering Proceedings 2018, 1, 91 .
AMA StylePanagiotis Athanasiou, Wiebe De Boer, Pieter Koen Tonnon, Jeseon Yoo, Matthieu De Schipper, Sierd De Vries, Roshanka Ranasinghe, Ad Reniers. LONG-TERM BAR DYNAMICS USING SATELLITE IMAGERY: A CASE STUDY AT ANMOK BEACH, SOUTH KOREA. Coastal Engineering Proceedings. 2018; 1 (36):91.
Chicago/Turabian StylePanagiotis Athanasiou; Wiebe De Boer; Pieter Koen Tonnon; Jeseon Yoo; Matthieu De Schipper; Sierd De Vries; Roshanka Ranasinghe; Ad Reniers. 2018. "LONG-TERM BAR DYNAMICS USING SATELLITE IMAGERY: A CASE STUDY AT ANMOK BEACH, SOUTH KOREA." Coastal Engineering Proceedings 1, no. 36: 91.
The Bight of Benin in the Gulf of Guinea, West Africa, forms an embayment between the Volta River delta in the west (Ghana) and the Niger River delta (Nigeria) in the east. The bight coast comprises sandy beaches backed by Holocene beach-ridge barriers. Incident swell waves, beachface gradient and the unidirectional longshore sand transport from west to east are intimately linked, generating a classic example of a strongly wave-dominated drift-aligned coast. The stability of this coast, which hosts several major cities in addition to three large international deepwater ports, has been strongly affected by human activities. We analyzed shoreline mobility and coastal area change over the period 1990-2015. Our results show how the stability of this coast has been strongly affected by the three ports therein, and by natural and human-altered shoreline dynamics related to the Volta River delta and to distributaries at the northwestern flank of the Niger delta. The combination of these factors has impacted alongshore sediment redistribution by segmenting the previously unrestrained longshore transport of sand that prevailed along this open coast. The result is a mixture of natural and artificial sediment cells increasingly dominated by shoreline stretches subject to erosion, endangering parts of the rapidly expanding port cities of Lomé (Togo), Cotonou (Benin) and Lagos (Nigeria), coastal roads and infrastructure, and numerous villages. Post-2000, the entire bight shoreline has undergone a significant decrease in accretion, which is here attributed to an overall diminution of sand supply via the longshore transport system. We attribute this diminution to the progressive depletion of sand-sized bedload supplied to the coast through the main Volta river channel downstream of the Akosombo dam, built between 1961 and 1965. Sand mining to cater for urban construction in Lomé, Cotonou and Lagos has also contributed locally to beach sediment budget depletion. Although alongshore sediment supply from the Volta River has been the dominant source of sand for the stability or progradation of the Bight of Benin coast, potential sand supply from the shoreface, and the future impacts sea-level rise on this increasingly vulnerable coast are also important. The continued operation of the three ports and of existing river dams, and sea-level rise, will lead to sustained shoreline erosion along the Bight of Benin in the coming decades.
E.J. Anthony; Rafael Almar; Manon Besset; J. Reyns; R. Laibi; Roshanka Ranasinghe; G. Abessolo Ondoa; Matteo Vacchi. Response of the Bight of Benin (Gulf of Guinea, West Africa) coastline to anthropogenic and natural forcing, Part 2: Sources and patterns of sediment supply, sediment cells, and recent shoreline change. Continental Shelf Research 2018, 173, 93 -103.
AMA StyleE.J. Anthony, Rafael Almar, Manon Besset, J. Reyns, R. Laibi, Roshanka Ranasinghe, G. Abessolo Ondoa, Matteo Vacchi. Response of the Bight of Benin (Gulf of Guinea, West Africa) coastline to anthropogenic and natural forcing, Part 2: Sources and patterns of sediment supply, sediment cells, and recent shoreline change. Continental Shelf Research. 2018; 173 ():93-103.
Chicago/Turabian StyleE.J. Anthony; Rafael Almar; Manon Besset; J. Reyns; R. Laibi; Roshanka Ranasinghe; G. Abessolo Ondoa; Matteo Vacchi. 2018. "Response of the Bight of Benin (Gulf of Guinea, West Africa) coastline to anthropogenic and natural forcing, Part 2: Sources and patterns of sediment supply, sediment cells, and recent shoreline change." Continental Shelf Research 173, no. : 93-103.
This paper focuses on utilizing Sentinel 2 MSI datasets to generate satellite-derived bathymetry (SDB) maps at a resolution of 10 m for two temporally varying datasets of the study region of Ameland Inlet, located in The Netherlands, by using support vector regression (SVR) technique. The relative performance of Landsat 8 OLI (30 m) datasets with SVR technique is also assessed to demonstrate the complementary nature of these freely available medium-resolution imageries. Further, the root mean square error and mean absolute error between the retrieved and measured bathymetries are estimated and reported to evaluate the capability of SVR in estimating depths. It is evident that the SDBs thus generated using this machine learning approach provide dependable estimations of depths that can further be utilized for various coastal engineering studies.
Ankita Misra; Balaji Ramakrishnan; Zoran Vojinovic; Arjen P. Luijendijk; Roshanka Ranasinghe. Assessment of Complementary Medium-Resolution Satellite Imageries for Nearshore Bathymetry Estimation. Journal of the Indian Society of Remote Sensing 2018, 47, 537 -540.
AMA StyleAnkita Misra, Balaji Ramakrishnan, Zoran Vojinovic, Arjen P. Luijendijk, Roshanka Ranasinghe. Assessment of Complementary Medium-Resolution Satellite Imageries for Nearshore Bathymetry Estimation. Journal of the Indian Society of Remote Sensing. 2018; 47 (3):537-540.
Chicago/Turabian StyleAnkita Misra; Balaji Ramakrishnan; Zoran Vojinovic; Arjen P. Luijendijk; Roshanka Ranasinghe. 2018. "Assessment of Complementary Medium-Resolution Satellite Imageries for Nearshore Bathymetry Estimation." Journal of the Indian Society of Remote Sensing 47, no. 3: 537-540.
Projected climate change driven variations in mean sea level (i.
Roshanka Ranasinghe; Ruben Jongejan. Climate Change, Coasts and Coastal Risk. Journal of Marine Science and Engineering 2018, 6, 141 .
AMA StyleRoshanka Ranasinghe, Ruben Jongejan. Climate Change, Coasts and Coastal Risk. Journal of Marine Science and Engineering. 2018; 6 (4):141.
Chicago/Turabian StyleRoshanka Ranasinghe; Ruben Jongejan. 2018. "Climate Change, Coasts and Coastal Risk." Journal of Marine Science and Engineering 6, no. 4: 141.
The Irrawaddy River Basin, Myanmar. Precipitation is the most important input variable to numerically simulate the hydrological responses of a river basin. Nowadays, a number of precipitation data products with different spatial and temporal resolutions are available. However, the accuracy of these products may vary greatly and the variations may themselves differ in different river basins. Such differences have direct implications on the use of these datasets in hydrological modelling. Here, using a hydrological model, we investigated the effects of four precipitation datasets (in-situ gauge precipitation with and without interpolation, PERSIANN-CDR, and CHIRPS) on streamflow simulations in the Irrawaddy Basin in Myanmar. We identified considerable differences in streamflow simulation with the use of different precipitation inputs. The four datasets showed varied annual and seasonal precipitation values over the basin. Although the gauge density within the study area is very low, streamflow simulations forced with interpolated gauge data outperformed the models forced with other datasets. However, simulations forced with CHIRPS and PERSIANN-CDR also showed good results in most cases in terms of Nash Efficiency and R2, but mostly with high biases. In calibration, the four precipitation inputs resulted in varied best-fitted parameter values and ranges. All the above observations indicate that the selection of suitable precipitation input(s) is necessary for an accurate investigation of the hydrological responses of any given basin.
T.A.J.G. Sirisena; Shreedhar Maskey; Roshanka Ranasinghe; Mukand S. Babel. Effects of different precipitation inputs on streamflow simulation in the Irrawaddy River Basin, Myanmar. Journal of Hydrology: Regional Studies 2018, 19, 265 -278.
AMA StyleT.A.J.G. Sirisena, Shreedhar Maskey, Roshanka Ranasinghe, Mukand S. Babel. Effects of different precipitation inputs on streamflow simulation in the Irrawaddy River Basin, Myanmar. Journal of Hydrology: Regional Studies. 2018; 19 ():265-278.
Chicago/Turabian StyleT.A.J.G. Sirisena; Shreedhar Maskey; Roshanka Ranasinghe; Mukand S. Babel. 2018. "Effects of different precipitation inputs on streamflow simulation in the Irrawaddy River Basin, Myanmar." Journal of Hydrology: Regional Studies 19, no. : 265-278.
One of the measures that has been implemented widely to adapt to the effect of climate change in coastal zones is the implementation of set-back lines. The traditional approach of determining set-back lines is likely to be conservative, and thus pose unnecessary constraints on coastal zone development and fully utilising the potential of these high-return areas. In this study, we apply a newly developed risk-informed approach to determine the coastal set-back line at regional scale in a poor data environment. This approach aims to find the economic optimum by balancing the (potential) economic gain from investing in coastal zones and the risk of coastal retreat due to sea level rise and storm erosion. This application focusses on the east coast of Sri Lanka, which is experiencing rapid economic growth on one hand and severe beach erosion on the other hand. This area of Sri Lanka is a highly data-poor environment, and the data is mostly available from global databases and very limited measurement campaigns. Probabilistic estimates of coastline retreat are obtained from the application of Probabilistic Coastline Recession (PCR) framework. Economic data, such as the discount rate, rate of return of investment, cost of damage, etc., are collated from existing estimates/reports for the area. The main outcome of this study is a series of maps indicating the economically optimal set-back line (EOSL) for the ~200-km-long coastal region. The EOSL is established for the year 2025 to provide a stable basis for land-use planning decisions over the next two decades or so. The EOSLs thus determined range between 12 m and 175 m from the coastline. Sensitivity analyses show that strong variations in key economic parameters such as the discount rate have a disproportionately small impact on the EOSL.
Ali Dastgheib; Ruben Jongejan; Mangala Wickramanayake; Roshanka Ranasinghe. Regional Scale Risk-Informed Land-Use Planning Using Probabilistic Coastline Recession Modelling and Economical Optimisation: East Coast of Sri Lanka. Journal of Marine Science and Engineering 2018, 6, 120 .
AMA StyleAli Dastgheib, Ruben Jongejan, Mangala Wickramanayake, Roshanka Ranasinghe. Regional Scale Risk-Informed Land-Use Planning Using Probabilistic Coastline Recession Modelling and Economical Optimisation: East Coast of Sri Lanka. Journal of Marine Science and Engineering. 2018; 6 (4):120.
Chicago/Turabian StyleAli Dastgheib; Ruben Jongejan; Mangala Wickramanayake; Roshanka Ranasinghe. 2018. "Regional Scale Risk-Informed Land-Use Planning Using Probabilistic Coastline Recession Modelling and Economical Optimisation: East Coast of Sri Lanka." Journal of Marine Science and Engineering 6, no. 4: 120.
Wave and tide induced sediment transport pathways and rates govern the morphological evolution of estuarine systems. An understanding of the morphodynamics of these systems is required to maintain their commercial, biological and recreational value. The morphodynamics of Port Stephens estuary, a micro-tidal estuary located on a wave dominated southeast coast of Australia were investigated using bathymetric surveys and current velocity data from several locations over the estuary. This provided detailed insight into the rates and direction of movement for the main sedimentary features of the system, and how these features interact with the processes that drive their evolution. We used these findings to develop a conceptual model for estuarine morphodynamics that accounts for fair weather and storm conditions. Our model explains how sediment eroded from the estuarine beaches is trapped by the adjacent flood-tide delta. The model is applicable to fetch-limited estuaries that do not have offshore sources of sediment, where the tidal currents are weak in relation to the incident ocean waves, and that have a wide, stable entrance through which ocean waves can propagate into the estuary. The model is multi-scale in that it encapsulates both short-term and local process, and large scale evolution of an estuary; therefore, it represents a tool that may be used in developing sustainable estuary management strategies.
Timothy P Austin; Ana Vila-Concejo; Andrew D Short; Roshanka Ranasinghe. A Multi-Scale Conceptual Model of Flood-Tide Delta Morphodynamics in Micro-Tidal Estuaries. Geosciences 2018, 8, 324 .
AMA StyleTimothy P Austin, Ana Vila-Concejo, Andrew D Short, Roshanka Ranasinghe. A Multi-Scale Conceptual Model of Flood-Tide Delta Morphodynamics in Micro-Tidal Estuaries. Geosciences. 2018; 8 (9):324.
Chicago/Turabian StyleTimothy P Austin; Ana Vila-Concejo; Andrew D Short; Roshanka Ranasinghe. 2018. "A Multi-Scale Conceptual Model of Flood-Tide Delta Morphodynamics in Micro-Tidal Estuaries." Geosciences 8, no. 9: 324.
Climate change triggers major alterations to coastal zones worldwide. Quantification of these adverse impacts to coastal ecosystems is often done on a coarse scale of global regions. Consistent local scale estimates of physical impacts on ecosystems and monetary assessment of associated losses are scarce, especially in developing countries. With aim of facilitating such assessment, which is increasingly required, here we propose a coherent three-step framework and subsequently apply it to quantify potential sea level rise-driven alterations in the monetary value of ecosystem services in the coastal area of Semarang in Indonesia. Within this framework, we (1) quantify the present value of coastal ecosystem services by using economic valuation techniques; (2) identify the potential impacts of relative sea level rise (RSLR)-induced inundation on ecosystem services (for the year 2100 inundation scenarios); and (3) monetize these impacts by developing a novel scenario-based approach. The results show that full inundation (scenario A with 4 m RSLR) poses a median loss of 90% (US$ 2.8 – 3.5) and 25% (US$ 90 – 113) to the present art and fishery values per hectare, while amenity service is expected to lose upto 50% (US$ 3700 – 5400) of its present value. Additionally, recreation value of the coastal ecosystems in three selected sites (Marina and Maron beaches, and Plumbon estuary) will decrease by 70% (US$ 15,460 – 19,820) per hectare. However, in scenario B (RSLR of 1.1 m) with a 50% inundated area, these losses are estimated approximately 40% less than for scenario A. It is expected that researchers and policy makers may apply this approach in their areas of interest to gain a better understanding of the likely costs of sea level rise-driven environmental damages along coasts, ultimately contributing to the sustainable management of coastal environment in Indonesia and possibly in other developing countries.
Seyedabdolhossein Mehvar; Tatiana Filatova; Ifdlol Syukri; Ali Dastgheib; Roshanka Ranasinghe. Developing a framework to quantify potential Sea level rise-driven environmental losses: A case study in Semarang coastal area, Indonesia. Environmental Science & Policy 2018, 89, 216 -230.
AMA StyleSeyedabdolhossein Mehvar, Tatiana Filatova, Ifdlol Syukri, Ali Dastgheib, Roshanka Ranasinghe. Developing a framework to quantify potential Sea level rise-driven environmental losses: A case study in Semarang coastal area, Indonesia. Environmental Science & Policy. 2018; 89 ():216-230.
Chicago/Turabian StyleSeyedabdolhossein Mehvar; Tatiana Filatova; Ifdlol Syukri; Ali Dastgheib; Roshanka Ranasinghe. 2018. "Developing a framework to quantify potential Sea level rise-driven environmental losses: A case study in Semarang coastal area, Indonesia." Environmental Science & Policy 89, no. : 216-230.
Understanding long-term sandbar dynamics can be crucial for informed coastal zone management, but is often hampered by data availability. To increase the number of sandbar observations available from bathymetric surveys, this study proposes and evaluates a method to manually extract the sandbar location using freely available satellite imagery for the case study of Anmok beach in South Korea. Validation of the satellite extracted sandbar locations against 9 in-situ measurements shows good agreement with errors well within the pixel resolution of the satellite imagery (i.e. 30 m for Landsat missions). The applicability of the method is constrained to locations where (1) the cross-shore crescentic length scales are larger than the image resolution, (2) frequent wave breaking and clouds are absent and (3) the water clarity is sufficient to enable the manual extraction of the sandbar crest line. Using the additional sandbar observations from the satellite imagery significantly increases the temporal extent and resolution of the dataset for Anmok beach. This allows the study of sandbar characteristics, dynamics and impacts of human interventions to an extent that would not have been possible without the satellite imagery. Within the study period 1990–2017 it is found that the sandbar maintains a persistent crescentic pattern that is only altered during prolonged and very intense storm conditions. The cumulative alongshore migration of the sandbars is investigated and found to be in the order of hundreds of meters over the 27 years study period. Comparing the sandbar characteristics prior and after the construction of Gangneung port shows that both the amplitudes and wavelengths of the sandbar crescents near the port have decreased after its construction.
Panagiotis Athanasiou; Wiebe de Boer; Jeseon Yoo; Roshanka Ranasinghe; Ad Reniers. Analysing decadal-scale crescentic bar dynamics using satellite imagery: A case study at Anmok beach, South Korea. Marine Geology 2018, 405, 1 -11.
AMA StylePanagiotis Athanasiou, Wiebe de Boer, Jeseon Yoo, Roshanka Ranasinghe, Ad Reniers. Analysing decadal-scale crescentic bar dynamics using satellite imagery: A case study at Anmok beach, South Korea. Marine Geology. 2018; 405 ():1-11.
Chicago/Turabian StylePanagiotis Athanasiou; Wiebe de Boer; Jeseon Yoo; Roshanka Ranasinghe; Ad Reniers. 2018. "Analysing decadal-scale crescentic bar dynamics using satellite imagery: A case study at Anmok beach, South Korea." Marine Geology 405, no. : 1-11.
Rip currents have an important control on the exchange of water and advected materials such as sediment and pollutants, between the surf zone and inner shelf. Concurrent in situ Eulerian and Lagrangian (GPS drifter) data of surf zone waves and currents were combined with video data on wave breaking patterns over the inner and outer bars on a high energy, double-barred beach. The data collectively show how the occurrence of wave breaking over the outer bar changes the behavior of a channel rip current, and the exchange process. On both days, there was a prominent clockwise eddy in the surf zone, for which the seaward-heading portion formed a rip current in a well-defined channel rip, incised into the inner bar. Exit rate (measured with drifters) from the surf zone to inner shelf decreased significantly with increased wave breaking over the outer bar, from 71% exits to 6% over the two days. Exit rate appears to be driven by the balance between wave breaking over the inner and outer bars and pulsing of currents within the surf zone. Under higher wave conditions, there were stronger pulsations in surf zone currents and more surf zone exits. However, higher wave conditions caused wave breaking over the outer bar. This breaking increases vorticity around the outside of the surf zone eddy, which increases surf zone retention. This is in contrast to previous studies showing that vorticity is highest at the center of surf zone eddies. Under such conditions, drifter exits were rare, and occurred due to vortex shedding. During lower incident wave conditions, eddy vorticity was lower, and drifters could relatively freely exit the surf zone. This is one of the few studies that investigate surf zone circulation on a high energy, double-barred beach.
Shari L. Gallop; Karin R. Bryan; Sebastian J. Pitman; Roshanka Ranasinghe; Dean R. Sandwell; Shawn R. Harrison. Rip current circulation and surf zone retention on a double barred beach. Marine Geology 2018, 405, 12 -22.
AMA StyleShari L. Gallop, Karin R. Bryan, Sebastian J. Pitman, Roshanka Ranasinghe, Dean R. Sandwell, Shawn R. Harrison. Rip current circulation and surf zone retention on a double barred beach. Marine Geology. 2018; 405 ():12-22.
Chicago/Turabian StyleShari L. Gallop; Karin R. Bryan; Sebastian J. Pitman; Roshanka Ranasinghe; Dean R. Sandwell; Shawn R. Harrison. 2018. "Rip current circulation and surf zone retention on a double barred beach." Marine Geology 405, no. : 12-22.
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
Arjen Luijendijk; Gerben Hagenaars; Roshanka Ranasinghe; Fedor Baart; Gennadii Donchyts; Stefan Aarninkhof. Author Correction: The State of the World’s Beaches. Scientific Reports 2018, 8, 11381 .
AMA StyleArjen Luijendijk, Gerben Hagenaars, Roshanka Ranasinghe, Fedor Baart, Gennadii Donchyts, Stefan Aarninkhof. Author Correction: The State of the World’s Beaches. Scientific Reports. 2018; 8 (1):11381.
Chicago/Turabian StyleArjen Luijendijk; Gerben Hagenaars; Roshanka Ranasinghe; Fedor Baart; Gennadii Donchyts; Stefan Aarninkhof. 2018. "Author Correction: The State of the World’s Beaches." Scientific Reports 8, no. 1: 11381.
Goneri Le Cozannet; Bulteau; Bruno Castelle; Roshanka Ranasinghe; Guy Wöppelmann; Jeremy Rohmer; Nicolas Bernon; Déborah Idier; Jessie Louisor; David Salas-Y-Mélia. Uncertainties of sandy shoreline change projections as sea level rises. 2018, 1 .
AMA StyleGoneri Le Cozannet, Bulteau, Bruno Castelle, Roshanka Ranasinghe, Guy Wöppelmann, Jeremy Rohmer, Nicolas Bernon, Déborah Idier, Jessie Louisor, David Salas-Y-Mélia. Uncertainties of sandy shoreline change projections as sea level rises. . 2018; ():1.
Chicago/Turabian StyleGoneri Le Cozannet; Bulteau; Bruno Castelle; Roshanka Ranasinghe; Guy Wöppelmann; Jeremy Rohmer; Nicolas Bernon; Déborah Idier; Jessie Louisor; David Salas-Y-Mélia. 2018. "Uncertainties of sandy shoreline change projections as sea level rises." , no. : 1.