Hansen, J.M.; Aagaard, T., and Kuijpers, A., 2015. Sea-level forcing by synchronization of 56- and 74-year oscillations with the Moon's nodal tide on the northwest European Shelf (eastern North Sea to central Baltic Sea).

The North Sea and Baltic Sea long-term records reveal a strong correlation (0.997) between sea-level changes and the sum of identified harmonic oscillations, corresponding to the lunar nodal period and four multiples of it. We developed a transparent method for iterative least residual sine regression that is capable of identifying harmonic sea-level oscillations, e.g., gravitational sea-level effects of the lunar nodal oscillation. Three relatively large harmonic sea-level oscillations with period lengths of 18.6 (18.6), 60.5 (55.8), and 76.1 (74.4) years correspond well to factors 1, 3, and 4 of the 18.6-year lunar nodal period (multiple periods in parentheses). The sum of these oscillations leaves small residuals that can be resolved into two further, statistically less significant oscillations with apparent period lengths of 28.1 (27.9) and 111.1 (111.7) years, corresponding to factors 1½ and 6 of the lunar nodal period. Periods and amplitudes expose strong entrainment, i.e. phase synchronization at rational ratios of the identified oscillations' periods as well as amplitude locking at reciprocal rational ratios of 1/2, 1/3, and 2/3 of the three largest oscillations. On top of the region's general sea-level rise (1.18 mm/y), strong quasi-oscillations occur when the two largest oscillations are in phase. Thus, a large quasi-oscillation commenced in 1971 adding a 40-year sea-level rise of 1.0–1.2 mm/y to the region's general sea-level rise. If our theory is correct, the ongoing quasi-oscillation should culminate in 2011, and the suggestion may be tested after completion of the ongoing 18.6-year nodal oscillation, i.e. in 2020–21. A purely mathematical extension of the oscillation parameters identified by the applied method suggests that the sum of harmonic oscillations produces 223-year pulses of quasi-oscillations, which can be divided into 158-year periods (e.g., 1747–1905 and after 1970) with large oscillations (60–65 mm), followed by 65-year periods (e.g., 1905–70) with much smaller oscillations (2–16 mm).

Roberts, H.H.; DeLaune, R.D.; White, J.R.; Li, C.; Sasser, C.E.; Braud, D.; Weeks, E., and Khalil, S., 2015. Floods and cold front passages: Impacts on coastal marshes in a river diversion setting (Wax Lake delta area, Louisiana).

Diversion of the Mississippi River is considered the most effective way of offsetting Louisiana's coastal plain land loss. The Wax Lake delta, a man-made diversion that represents mostly sand-rich distributary mouth bar deposits, is cited as a model for land building from a large river diversion. The fine-grained suspended load is mostly deposited outside of “the delta.” Numerical simulations of diversion delta building focus primarily on sand deposition. The fine-grained suspended load is only secondarily considered. Research results reported here suggest that natural processes associated with the synergistic relationship between floods and cold front passages can effectively distribute suspended sediments to maintain and rebuild wetlands outside the sand-rich delta. Measurements (fixed acoustic Doppler current profilers) of current speed, current direction, and water level in a mainland marsh channel, north of Atchafalaya Bay, indicate that as cold fronts approach, local water levels can be elevated by as much as 1 m, and normal discharge into the bay is reversed so that flow is into the coastal plain marshes. LIDAR bank elevations indicate that overbank flow is initiated by these events. Streamside sediment accretion (2-y monitoring period) using feldspar plots indicates up to 6.8 cm. Longer term Cs-137 data reveal an average sediment accretion rate of >1 cm y⁻¹ over 50 years. Marsh flooding results in denitrification of nitrate in river water plus nutrient uptake resulting in increased plant productivity, considerably greater than for similar coastal plain marshes free of riverine sediment input. Fine-grained suspended sediments are important for rebuilding Louisiana's coastal plain, which is naturally constructed mostly of riverine silt and clay plus organic matter.

Currin, C.; Davis, J.; Cowart Baron, L.; Malhotra, A., and Fonseca, M., 2015. Shoreline change in the New River Estuary, North Carolina: Rates and consequences.

Aerial photography was used to determine rates of shoreline change in the New River Estuary (NRE), North Carolina, from 1956 to 2004. The NRE shoreline was digitized from aerial photographs taken in 1956, 1989, and 2004, and shoreline type was determined by ground-truthing the entire shoreline by small boat in 2009. Major shoreline type categories included swamp forest (6% of total), salt marsh (21%), sediment bank (53%), and modified/hardened (19%). Ground-truthing provided additional details on relief, marsh species composition, and structure type. A point-based, end-point rate approach was used to measure shoreline change rate (SCR) at 50 m intervals for the periods 1956–89, 1989–2004, and 1956–2004. Representative wave energy (RWE) was modeled for each interval using local bathymetry and wind data. Average SCR across all shoreline types for the entire time period ranged from −2.3 to 1.0 m y⁻¹, with a mean SCR of −0.3 m y⁻¹. This translates to an average loss of ~13 m for any given point over the 48-year period covered by this study. The most negative average SCR (greatest erosion) occurred along unvegetated sediment bank shorelines (−0.39 m y⁻¹). Change along marsh shorelines (−0.18 m y⁻¹) was lower than along sediment banks, and narrow fringing marsh associated with sediment bank shorelines significantly reduced bank erosion. Modeled RWE values were positively correlated with erosion only in the highest wave-energy settings. Erosion of sediment bank shorelines provides a conservative estimate of 17,660 m³ of sediment each year to the estuary, with marsh erosion contributing up to an additional 1900 m³ y⁻¹. Based on analysis of the sediment volume required to maintain marsh surface elevation with respect to sea level, we hypothesize that shoreline erosion plays a vital role in supporting growth and maintenance of downstream marshes.

Kriebel, D.L.; Geiman, J.D., and Henderson, G.R., 2015. Future flood frequency under sea-level rise scenarios.

The effect of sea-level rise (SLR) on exceedance probabilities for annual flooding at coastal locations is explored in this paper. We assess four future SLR scenarios given by the U.S. Army Corps of Engineers and how these SLR scenarios affect monthly flooding statistics. Focusing on one case site, Annapolis, Maryland, we fit the probability density function of the monthly maximum tide gauge record with a Pareto-tail distribution. Random sampling from this distribution is then performed on top of the various future SLR scenarios. Exceedance probabilities for a storm tide to exceed the coastal flood stage, the elevation of which has already been established in a previous paper, are then calculated from the interpolated Pareto cumulative distribution. We illustrate that even mild increases in mean sea level acceleration lead to drastically higher exceedance probabilities of coastal flooding.

Cuc, N.T.K. and Ruyter van Stenvenick, E.D. de, 2015. Production function of planted mangroves in Thanh Phu Nature Reserve, Mekong Delta, Vietnam.

Through assessment of forest structure, biomass of mangrove plantations in the Thanh Phu Nature Reserve, Mekong Delta, Vietnam was analyzed in correlation with diameter at breast height (DBH, i.e. at 1.3 m height). Study plots were set up in 7, 11–22, and 26-year-old planted Rhizophora apiculata Blume plantations. There is a significant inverse correlation between DBH and tree density (R² = 0.73; p < 0.01). To derive an allometric relation to estimate aboveground biomass, 32 trees representing all ages were chosen randomly and harvested at ground level to examine allometric relations. We measured the fresh and dry weight of stems (W_S), branches (W_B), leaves (W_L), and aboveground stilt roots (W_R) in situ. Allometric relationships were satisfied best with DBH as an independent variable (R² = 0.72, 0.89, 0.87, 0.98, and 0.97 for leaves, branches, stilt roots, stem, and total aboveground biomass, respectively; p < 0.001). The total aboveground biomass was estimated in the plantations to vary between 76 and 320 tons/ha. Of this, more than 50% of total aboveground biomass was represented by stems. The estimated biomass value of this study is consistent with that of other mangroves in the world. Total biomass of R. apiculata plantation in Thanh Phu Nature Reserve accounted for about 170,057 tons dry weight or 8056 tons C.

Dai, H.; Ye, M., and Niedoroda, A.W., 2015. A model for simulating barrier island geomorphologic responses to future storm and sea-level rise impacts.

This paper presents the Barrier Island Profile (BIP) model, a new computer code developed to simulate barrier island morphological evolution over periods ranging between years and decades under the impacts of accelerated sea-level rise and long-term changes in the storm climate. The BIP model is a multiline model that represents the time-averaged dynamics of major barrier island features from front beach to backshore. Unique contributions of BIP to coastal modeling include a dynamic linking of interacting barrier island features and consideration of both future sea-level rise and storm climate impacts. The BIP model has the built-in capability of conducting Monte Carlo (MC) simulations to quantify predictive uncertainty caused by uncertainty in sea-level rise scenarios and storm parameters. For a series of barrier island cross-sections derived from the characteristics of Santa Rosa Island, Florida, BIP was used to evaluate their responses to random storm events and five potential accelerated rates of sea-level rise projected over a century. The MC simulations using BIP provide multiple realizations of possible barrier island morphologic responses and their statistics, such as mean and variance. The modeling results demonstrate that BIP is capable of simulating realistic patterns of barrier island profile evolution over the span of a century using relatively simple representations of time- and space-averaged processes with consideration of uncertainty of future climate impacts.

James, K.F.; Bourman, R.P., and Harvey, N., 2015. Rapid evolution of a flood tidal deltaic island in the River Murray estuary, South Australia: A canary in the cage of river management.

Bird Island, at the oceanic outlet of Australia's largest exoreic river system, the Murray-Darling, did not exist before 1940. Originally, flood tidal sediments were moulded by tides, waves, wind, and river flows in the back-barrier lagoon, landward of the migrating River Murray Mouth. The estuary was fluvially dominated, and the terminal lakes were mainly fresh. Following more than a century of European settlement and freshwater abstraction, salinity levels increased, prompting the construction of barrages (completed in 1940) near the Murray Mouth to restore the former predominantly freshwater character of the estuary. Further reduced river flows, a restricted tidal prism, and management strategies produced irreversible changes in the dynamics of the River Murray Mouth. These are archived in the landforms and vegetation of Bird Island. By the mid-1950s, sand shoals were enlarging and a small patch of vegetation was established, forming the core of an incipient island. Progressively, dunes and salt marshes were established, reflecting intimate associations between landform evolution, vegetation colonisation, and island stability. As the mouth migrated to the NW, so did the flood tidal shoals, the sources for newer generations of dunes, thereby developing a clockwise establishment of dunes on the expanding island. Approximately 1 km in diameter and carrying more than 80 plant species, Bird Island assisted mouth closure in 1981. During the 2002–10 drought, dredging maintained the mouth and improved lagoonal water quality. Subsequent healthy river flows cleared the mouth, highlighting the important role of river flows in maintaining oceanic access, and sediment removal, while flushing the river system. The evolution of Bird Island as documented in this study demonstrates how anthropogenic activities can cause rapid and irrevocable changes to coastal–estuarine environments.

Liao, C.C.; Jeng, D.-S., and Zhang, L.L., 2015. An analytical approximation for dynamic soil response of a porous seabed due to combined wave and current loading.

This paper presents a new analytical approximation for wave (current)–induced dynamic soil response. In this study, unlike in previous research projects, full dynamic soil behaviour was considered. The nonlinear waves propagating over an infinite seabed with uniform current were investigated, and the new analytical solution was validated with the previous field observations and laboratory experiments. The effects of currents and wave nonlinearity were examined based on the proposed analytical solution. Finally, a parametric study was carried out to examine the influence of the wave and seabed characteristics on the seabed response. As the numerical examples demonstrated, the effects of currents on the seabed response are significant only in the top region of the seabed (comprising approximately 10% of the wavelength). Based on parametric study, it is concluded that currents with third-order wave loading and full dynamic soil behaviour cannot always be ignored in the estimation of the wave-induced seabed responses, especially for almost-saturated soil, long-wave periods, and shallow water. A significant difference was also observed in the maximum liquefaction depth between the full dynamic and the consolidation models.

Lucrezi, S. and van der Merwe, P., 2015. Beachgoers' awareness and evaluation of the Blue Flag Award in South Africa.

Beach awards such as the European Blue Flag are increasingly adopted in many countries as an environmental brand to promote better beach management and encourage tourism. However, the validity of the Blue Flag award has been criticized in the literature, and research shows that the award is still not widely known and has marginal influence on tourists' beach selection. This study, conducted at six popular South African beaches, three with and three without Blue Flag status, investigated awareness and evaluation of the Blue Flag award among 579 beachgoers. Results from a structured questionnaire showed that over half of the participants, mostly people on the Blue Flag beaches, knew about the Blue Flag award and its criteria; however, approximately one-third of the participants were unaware of it. Participants tended to be less tolerant of supposed water-quality degradation than the loss of the Blue Flag status, although an exception was made for Margate Beach, where people were less tolerant of a hypothetical loss of Blue Flag status. Although the participants' evaluation of the Blue Flag award was generally positive, for most it was not their main reason for visiting a beach. In the light of these findings, a more coherent implementation of the Blue Flag award and better information propagation in its regard are recommended for South African beaches.

Hsu, T.-W.; Doong, D.-J.; Hsieh, K.-J., and Liang, S.-J., 2015. Numerical study of monsoon effect on Green Island wake.

The wind effect on Kuroshio-induced island wake downstream of Green Island, Taiwan, is studied using a depth-averaged shallow-water model. The seasonal monsoon effect on spatial–temporal scales, such as the aspect ratio, dimensionless width, and Strouhal number, as well as the relative propagation speed of Green Island vortices, is studied. It is found that a NE monsoon has a more pronounced effect on wake characteristics than a SW monsoon does in terms of net speed and vorticity, aspect ratio, and dimensionless width. Vortices are pushed back and packed close to the north of the island with a smaller area of recirculation when Kuroshio flows against the NE monsoon; vortices are pushed farther downstream with a larger area of recirculation when Kuroshio flows in favor of the SW monsoon. However, the wind effect on temporal variation of island wake seems less significant. The period of vortex shedding is between 14.2 and 15.3 hours. The corresponding Strouhal number is between 0.116 and 0.125, and the relative propagation speed of vortices is nondimensional, between 0.51 and 0.56. These values are in good agreement with the results of previous reports.

Shah, P.; Sajeev, R., and Gopika, N., 2015. Study of upwelling along the west coast of India—A climatological approach.

With extensive use of satellite-measured climatology, the present study investigated the upwelling along the entire west coast of India and authenticated the differences in upwelling along the SW and NW coasts. During May and September, the entire west coast of India was characterized by weak offshore surface mass transport. During June, July, and August, offshore surface mass transport was limited to SW coast of India, and onshore transport was observed along NW coast, except at 16° N and 17° N, where very weak offshore transport was observed, compared with SW coast. Analysis of the Sea Surface Height Anomaly, depth of 26° isotherms, and Local Temperature Anomaly revealed the role of remote forcing on the upwelling along the west coast of India, especially during the peak summer monsoon months. The observations on the Local Temperature Anomaly at different depth levels exposed that, at the surface, the upwelling features was limited to the SW coast of India during the summer monsoon. Upwelling, however, was clearly evident at the 10-m depth along the NW coast during May and September. The main difference in upwelling along the SW and NW coastlines during June to August was that vertical excursion of upwelled water along the NW coast was limited to the 30-m depth and along the SW coast; the upwelled water replaces the surface water. From Local Temperature Anomaly it was also evident that the intensity and south to north propagation speed of upwelling was more at deeper level than at the surface.

Chun, I.; Lim, H.S.; Shim, J.S., and Park, K.S., 2015. Numerical analysis of the performance of perforated coastal structures under irregular wave conditions.

A numerical and experimental study was performed to investigate the wave control characteristics of general perforated harbor structures under irregular wave conditions. A numerical analysis using a boundary element method was applied to each of the regular wave components composing the irregular wave, and the results were linearly superimposed under linear wave assumptions. The nonlinear friction term at the perforated walls was first linearized using the root mean square values of horizontal velocity components obtained through an iterative calculation. Hydraulic experiments were also performed for three different transmissive structures, and the results were compared with those of the numerical analysis. The numerical and experimental values of reflection and transmission coefficients generally agreed within an accuracy of 0.1. The numerical analysis was also applied to a nontransmissive structure with a single wave chamber from a previous experiment and showed good agreement with those experimental results.

Marrack, L., 2015. Incorporating groundwater levels into sea-level detection models for Hawaiian anchialine pool ecosystems.

As sea levels rise, the distribution and community structure of coastal ecosystems are expected to change. In many coastal aquifers, fresher groundwater floats on top of denser saltwater and will rise with sea level. Under these conditions, ecosystems dependent on groundwater may shift inland as a result of inundation, changes in salinity, or both. Groundwater-fed anchialine pool habitats existing in porous coastal substrates around the world have not been assessed for sea-level rise impacts. As a first step toward examining ecosystem response to rising water levels, geospatial models were developed to detect anchialine pools on the island of Hawai‘i at current water levels and models were validated with known pool locations. Specifically, the objectives were to determine whether accounting for groundwater levels in the model improved pool detection, to identify the model that most accurately detected known pools, and to identify which pool features make some pools more likely to be detected than others. Six water level models were validated with the test data set of actual pool locations to determine how well they detected known anchialine pools. Water surface models that included groundwater levels were up to 37% better at detecting anchialine pools than corresponding models without groundwater levels. The model that included groundwater levels at mean higher high water was applied to 42 km of coastline where it correctly detected 62% of known pools. A generalized linear model showed that pools with surface areas greater than 5 m² and pools without canopy were the most likely to be detected. Future predictive modeling of anchialine pool response to sea-level rise should include groundwater levels. Furthermore, geospatial models aimed at predicting ecosystem shifts due to sea level rise may be improved by including groundwater as a factor and should be validated using current ecosystem conditions.

Fang, S.C.; Chang, I.-C., and Yu, T.Y., 2015. Analysis of spatial features of coastal oil pollution using multivariate methods.

Coastal water quality plays an important role in people's lives. In this study, the coastal water of the Penghu archipelago was used as a research object. Three types of multivariate methods—factor analysis, cluster analysis, and multivariate scaling—were employed to analyze the spatial features of oil pollution, and the results of these three methods were compared with regard to the causes of pollution. Factor analysis showed that oil concentration subregions, composed of the first four principal components, accounted for 84.8% of the oil concentration variance. The contour maps of factor loadings of each principal component, combined with the distribution of pollution sources, the direction of seawater flow, etc., might be appropriate to interpret the pollution patterns represented by each principal component. Based on the comparison of the advantages and disadvantages of the three multivariate methods used to explain the geographical features of oil concentration, factor analysis was the best analytic approach in that it could provide information of proportional contributions from a variety of pollution sources on oil concentration variance; it also provided appropriate spatial classification results and a classification number. Factor analysis and multivariate scaling could divide the region into four subregions with consistent oil concentrations. The possible pollution sources in each subregion could be interpreted by locations of sources, contour maps of factor loadings, and relevant factors. Although cluster analysis could differentiate the concentrations measured by all observation stations, its geographical classification result was worse than those of the other two methods.

Clemente, I.M.M.M.; da Silva, F.S.; Laut, L.L.M.; Frontalini, F.; da Costa, V.L.; da Conceição Rodrigues, M.A.; Pereira, E.; Bergamaschi, S.; Filho, J.G.M., and Martins, M.V.A., 2015. Biochemical composition and foraminiferal content of sediments for determining bottom sector environments in Guanabara Bay (Rio de Janeiro, Brazil).

Three cities in Brazil—Rio de Janeiro, Niterói, and São Gonçalo—with an estimated total population of 11 million people, are located in the surroundings of Guanabara Bay (RJ-Brazil), making it a highly contaminated coastal system. Because of its importance, Guanabara Bay has been one of the most studied coastal environments in Brazil. Despite that, this study represents the first investigation, to our knowledge, to couple benthic foraminifera with the quantity and quality of organic matter in the area. The spatial distribution of water salinity and the surface sediment reduction potential, grain size, total organic carbon, sulfur, bacterial organic carbon, biopolymers such as carbohydrates, proteins, lipids, bacterial enzyme esterase, and total foraminiferal assemblages were studied at 30 stations in Guanabara Bay. Based on these data, six bottom environments—industrial, marginal urban, marginal urban/industrial mixing, eutrophic, transitional, and outer— were identified and described.

Taylor, E.B.; Gibeaut, J.C.; Yoskowitz, D.W., and Starek, M.J., 2015. Assessment and monetary valuation of the storm protection function of beaches and foredunes on the Texas coast.

Beaches and dunes dampen wave energy and protect against storm surge. This protection is not uniform and varies according to geomorphic characteristics along the coast. Barrier island communities should identify the protection afforded by beaches and dunes to better assess their vulnerability and inform decision making regarding management alternatives. Our study presents a classification identifying a theoretical level of protection that beaches and foredunes could provide against overwash resulting from a tropical storm or hurricane along Mustang and North Padre Islands, Texas. In addition, a monetary valuation of this protective function is estimated at a site level. The theoretical level of storm protection was determined by assessing the response of representative beach-dune profiles to a set of synthetic storms and identifying the storm level at which profiles were overwashed. A monetary value was then assigned to the storm protection function of beach-dune profiles using a replacement cost approach. The level of protection afforded by beaches and foredunes varies across the islands. Some areas are more vulnerable to overwash and inundation during low-intensity storms. About 50% of the assessed beach-dune profiles provide overwash protection against at least a 100-year storm. Areas with the highest protection levels (100 and 200 y) share the following characteristics: (1) they have high dunes (>4 m in elevation), (2) they are in largely undeveloped areas or where buildings are at least 150 to 200 m landward of the line of vegetation, and (3) they generally have a wider beach–foredune complex width. The total annual value of the storm protection function of beaches and foredunes is estimated to be $141.4 million (USD 2013, replacement cost equivalent).

Castro-Santos, L. and Diaz-Casas, V. 2015. Cost comparison of three floating offshore wind platforms.

This paper proposes a method to calculate the total cost of a floating offshore wind farm. The method is based on the phases of the life cycle of such a farm. Each phase is defined by a cost, the value of which is either a constant or a variable parameter depending on the characteristics of a particular region. The tool so developed results in a georeferenced map of the total cost implied in the development of a floating offshore wind farm. Additionally, this method is applied to a floating offshore wind farm located in Galicia (in northwest Spain), as well as the three most important types of floating platforms: semisubmersible, tensioned leg, and spar. This paper is novel in that it helps to estimate the economics of floating offshore wind farms. In this sense, this study is one of the first of its kind to calculate the various costs associated with these types of wind farms.

Purvis, K.G.; Gramling, J.M., and Murren, C.J., 2015. Assessment of beach access paths on dune vegetation: Diversity, abundance, and cover.

Coastal human populations are expanding and affecting plant communities, in particular dune systems. Coastal communities face risks from storm events, while coastal dune systems are heavily affected by human population and recreation pressures. Here, we evaluate the impacts of human disturbance (beach access paths) on vegetative cover and plant diversity in coastal dunes on the Isle of Palms, South Carolina. Transects were created in the foredune, middune, and backdune vegetation communities, and plots were placed 0, 1.5, 5, 10, and 20 m from a path to assess the impacts of three types of paths (public sand paths, private sand paths, and private wooden paths) at these distances on diversity, abundance, and measures of cover. Results indicate that beach access paths reduce biodiversity and density of beach dune vegetation. Sand paths contribute to greater reductions in vegetative cover than all wooden paths. Raised wooden paths compared to those at the sand surface have the least reduction in vegetation cover. Areas between closely spaced paths had reduced species richness and reduced percentage of vegetative cover compared to areas where paths were spaced at least 40 m apart. Dune vegetation plays a critical role in dune ecosystems by trapping and stabilizing sand. Areas of the dune that have reduced plant species diversity or lower levels of vegetation coverage are more prone to erosion and provide lower-quality habitat for other taxa. Current municipal regulations can be minimally altered to improve dune vegetation cover and richness while creating minimal inconvenience for beachfront homeowners and visitors.

Jones, R., 2015. Quantifying extreme weather event impacts on the northern Gulf Coast using Landsat imagery.

Recent high-profile hurricanes have demonstrated the destructiveness of extreme events on coastal landscapes to the world. Barrier islands across the planet are disappearing, exposing vulnerable coastal cities to the damage caused by extreme events. Growing resolve among scientists regarding climate change's connection to tropical cyclones heightens the concern around intensifying extremes and landscape dynamics. This study uses more than 600 Landsat images to examine the role of extreme events on barrier island morphology on three of the Mississippi–Alabama barrier islands from 1972 to 2013. Each island, West Ship Island (WSI), East Ship Island (ESI), and Petit Bois Island (PBI), was measured for area in hectares 14 times per year on average with higher temporal resolution before and after hurricanes, allowing for a high-resolution statistical history of surface area change and the quantification of the impact of extreme weather events. The results reveal that extreme events, specifically hurricanes, mid-latitude cyclones, and thunderstorms, shape the islands more than gradual erosion and accretion processes across all islands. Thunderstorms, winter cyclones, and tropical cyclones each affect the island in different ways, eroding from different areas upon impact. Catastrophic events caused 52–59% of all land area change on the islands during the study period. Hurricanes caused 27–37% of all change across the islands, thunderstorms 11–13%, and mid-latitude cyclones 11–14%. Each of the islands lost at least one-quarter of its 1972–73 areas: WSI 25%, ESI 39%, and PBI 38%. WSI and ESI are both in post-Katrina (2005) regrowth periods, whereas PBI continues to experience net erosion.

Sander, L.; Raniolo, L.A.; Alberdi, E., and Pejrup, M., 2015. Elevation trends in wide beach-ridge systems retrieved from Landsat images and the SRTM digital surface model.

Beach-ridge systems are a common feature of prograding coastlines and they have been recognized as important archives of late Quaternary sea level. In this paper, the combination of Landsat images and shuttle radar topography mission (SRTM) surface model data is shown to provide a solid base to assess gross elevational trends in wide beach-ridge systems. The tilt of a strand plain is a useful first indication to assess possible scenarios of long-term relative sea-level development at new field sites. We identified morphological landscape units for a large and complex coastal lagoon system in NE Patagonia (Argentina) on the basis of a series of Landsat satellite images. A good correlation (R² = 0.92) was found for the comparison of high-resolution GPS data with the extracted corresponding SRTM elevations of a 3.8-km-long transect across a wide strand plain. This suggests that the surface model is able to reproduce changes in average elevation between distal and proximal beach-ridge sets at a relatively high accuracy. The SRTM data set is a source of freely available data to approach elevation trends in prograded beach-ridge systems in Quaternary coastal environments. The combination of SRTM data with Landsat images presents a useful tool and source of information for the preparation of fieldwork and detailed surveys as well as for the formulation of working hypotheses in poorly described areas.

Amin, R.; Ritter, E., and Wetzel, A., 2015. An estimation of shark-attack risk for the North and South Carolina coastline.

A spatiotemporal cluster analysis of shark-attack rates is applied to identify coastal areas with shark-attack rates that are very high or very low along the North and South Carolina coast. Using a cluster analysis makes it possible to not just pinpoint these areas with more accuracy but also identify where incidents are unlikely to happen. In the past, shark attacks have been studied from a viewpoint of encounter number per region and so limited to the areas in which the attacks occurred. A first look is also taken of the potential influences of some anthropogenic, environmental, and meteorological factors for North and South Carolina in comparison with the better-known attack-prone areas along Florida's coast, to quantify potential causes leading to elevated shark-attack rates, or the lack of them.

Klemas, V.V., 2015. Coastal and environmental remote sensing from unmanned aerial vehicles: An overview.

Unmanned aerial vehicles (UAVs) offer a viable alternative to conventional platforms for acquiring high-resolution remote-sensing data at lower cost and increased operational flexibility. UAVs include various configurations of unmanned aircraft, multirotor helicopters (e.g., quadcopters), and balloons/blimps of different sizes and shapes. Quadcopters and balloons fill a gap between satellites and aircraft when a stationary monitoring platform is needed for relatively long-term observation of an area. UAVs have advanced designs to carry small payloads and integrated flight control systems, giving them semiautonomous or fully autonomous flight capabilities. Miniaturized sensors are being developed/adapted for UAV payloads, including hyperspectral imagers, LIDAR, synthetic aperture radar, and thermal infrared sensors. UAVs are now used for a wide range of environmental applications, such as coastal wetland mapping, LIDAR bathymetry, flood and wildfire surveillance, tracking oil spills, urban studies, and Arctic ice investigations.

Vollmer, H.M.; Finkl, C.W., and Makowski, C., 2015. Novel method for interpreting submarine geomorphology from LADS bathymetry using Surfer^® 12 shaded relief maps.

Laser Airborne Depth Sounding (LADS) produces high-resolution x, y, z surface data of seafloor topography that permits interpretation of geomorphological features, benthic environments, and habitats, as well as recognition of cultural features and submarine engineering structures. Because the quality of the resulting surface data depends on the type of processing software, it is worthwhile to consider potential improvements of previous bathymetric imagery displays generated from LADS data. A novel method for formatting, gridding, and exporting LADS data into Surfer^® 12 software is shown to produce enhanced quality surfaces that facilitate shaded relief map analysis. This new Surfer 12 shaded relief map creation procedure intensifies the interpretation of submarine geomorphology from LADS bathymetry images in a GIS platform environment.

Oakley, A.; Cornell, S.; Bochicchio, C.; Carney, J., and Sabetta, M., 2015. Using groundwater data sondes to produce high-quality in situ tide and wave hydrographs along Wallops Island, Virginia.

The challenges to coastal regions posed by rising sea levels will differ from community to community. In situ wave and tide time-series data are vital for calibrating numerical coastal models used to predict and mitigate the effects of coastal flooding and high-energy erosive waves and to inform coastal engineering projects. However, for many communities, local, high-quality data sets do not exist. Here, we present a proof-of-concept study for a new method to collect local, low-cost, and high-quality, nearshore hydrographs that can be used to calibrate and test coastal models. In 2011, we deployed self-contained pressure sensors at ocean- and bay-side locations along Wallops Island, Virginia, home of the National Aeronautics and Space Administration Wallops Flight Facility. We used a linear array of data loggers to characterize nearshore wave morphology at two sites along the barrier island beach. During the period of observation, wave height and frequency were both higher along the southern, eroding portion of Wallops Island. We also installed stilling wells in a tidal creek and at the Curtis Merritt Harbor (CMH) on Chincoteague Island to compare tide levels, range, and lag between the back bay and the inlet. Our data show an approximately 1-hour lag between sites, which contrasts with existing forecasted tidal lags in the region that range from 9 minutes to nearly 2 hours. These data loggers are a less-expensive alternative to traditional hydrographic equipment, such as acoustic Doppler current profilers, and can be used in shallow, nearshore environments where buoy-deployed level sensors are impractical. These instruments can be used for specific studies that range in time from a few minutes to a few years; are capable of high-resolution time series (1 Hz); can be installed rapidly as single units or deployed as low-cost, multinode arrays; and can even be used to investigate individual storm events.

de Jager, A.L., 2015. Feasibility of a worldwide coastal reference and coding system based on the IHO ocean and seas definition.

Coastlines form the geometric basis of common GISs. For example, country borders must match the coastline, rivers flow up to the coastline, and a variety of legislation applies up to a defined distance from the coastline. In this article, we propose a well-defined coastline in a structured GIS format that complies with the International Hydrographic Organization (IHO) ocean and sea definitions. Once this line structure has been defined and digitized to an agreed accuracy, it may be used as a building block—for example, for matching river mouths and country borders to the coastline—and for additional functions such as creating a hydrographic coding system. A coding mechanism has been developed based on available mathematical formulas, which enables the rapid computation of similar codes based on any high-quality geometric data. An application of the system is demonstrated in order to assess how grouping and ordering data along a coastline may be explored. Analysis of the coding system also enables an assessment of how coastline length can be compared with data originating from different sources and/or morphology.