Bernasconi, M.P. and Stanley, J.-D., 2014. Post-Greek coastline shifts interpreted by biostratigraphic analysis on Hipponion's seismotectonically active margin, Calabria, Italy.

Coastline migrations since the Greek period are identified on the seismotectonically active Tyrrhenian margin near ancient Greek Hipponion (Vibo Valentia), in SW Calabria, Italy. The study area is characterized by the Trainiti River mouth area, with its small delta-shaped protuberance and two large, submerged, coast-abutting breakwaters that once delineated a harbor for late Greek, Roman, and subsequent settlements. Biogenic facies and ecological analyses define the depositional settings of late Holocene sediment sections in cores recovered on shore just landward of the harbor's eastern breakwater. Radiocarbon-dated biogenic facies in the cores show sediments accumulated in inner-shelf settings to depths of about 10 m, indicating the coastline had retreated about 200 to 300 m landward of its present position from about the late Greek and Roman periods to the 13th century AD. This phase was followed by seaward advance of the shore, resulting in shallower, current-formed, offshore bar to forebeach settings during and following the medieval time that originated the delta-shaped body. The latter, positioned behind the eastern breakwater, is anomalous in that it formed on an otherwise straight coastline subject to active structural displacement and erosion. A thin upper veneer of deltaic sediment indicates that the Trainiti mouth reached the study area within the past 300 years, its channel having migrated from the west. Post-Greek tectonic displacement of this coastal margin resulted in the seaward-tilted configuration of the eastern breakwater, originally constructed as a coast-detached structure with a horizontal surface on the inner shelf. As the shoreline advanced seaward during the past approximately 800 years, the gap between land and offshore breakwater narrowed, altering coastal sedimentation processes and topography. It is proposed that vestiges of major Greek and Roman port facilities and settlements on land are likely buried by a thick alluvial cover on the coastal plain, probably south and west, rather than just landward, of the eastern breakwater study area.

Dean, R.G.; Wells, J.T.; Fernando, H.J., and Goodwin, P., 2014. Sediment diversions on the lower Mississippi River: insight from simple analytical models.

River diversions offer a mechanism by which sediment-laden waters can be introduced into interdistributary basins and bays to build new land that provides a substrate for wetland growth. Two geometric models were developed to allow calculation of future performance of river diversions with emphasis on the Mississippi River. These geometries, a truncated cone and a uniform width geometry, assume a constant discharge of sediment into the receiving basin and thus avoid many of the complexities of the evolutionary processes. Model results from both geometries show a clear life cycle of growth and deterioration in a diversion that experiences relative sea level rise and, under certain combinations of relative sea level rise, depth of receiving waters and sediment discharge rate, situations in which a subaerial platform will never form. A comparison of subaerial deposits in larger versus smaller diversions, assuming the same total sediment discharge in both cases, reveals that the total subaerial land area for the larger diversions is substantially greater than the sum of the two volumes of the smaller diversions. Model results have been used to illustrate, through examples, the effect of bottom slope and sea level rise on diversion performance. Recommendations have been made for the selection (quantification) of diversion parameters to be used in the models. These include annual sediment input, proportion of sediment retained in the diversion deposit, sediment bulking factor, foreset slope, and subsidence rate. Other required input parameters are considered to be known, namely, average diversion water discharge, initial depth of receiving waters, bottom slope, deposit angle or width, and future sea level rise. We also include general recommendations for selection and utilization of diversion sites.

Rufin-Soler, C.; Mörner, N.-A.; Laborel, J., and Collina-Girard, J., 2014. Submarine morphology in the Maldives and Holocene sea-level rise.

An underwater survey of the Maldives archipelago has documented various types of erosion features in the Pleistocene reef rock record. Among these were several littoral notches, whose equivalent is found in many other parts of the world. The morphology of the notches at −24 and −35 m suggests that the decelerations of the Holocene transgression were true standstills, or episodes of very slow rise, followed by episodes of rapid rise of the water level. Some deeper water notches were also surveyed. Many caves and cavities in the Pleistocene reef rock, although excavated during low glacial levels, appear to have also been reworked by marine erosion during the Holocene rise. Deep dissection of old cavities by bioerosive action leads to frail, hooplike formations, unable to stand their own weight on dry land. Despite the difficulty of dating such formations as notches, their correspondence with similar features observed in other regions is striking.

Peek, K.M.; Mallinson, D.J.; Culver, S.J., and Mahan, S.A., 2014. Holocene geologic development of the Cape Hatteras region, outer banks, North Carolina, USA.

Micropaleontological, geophysical, and chronologic data indicate that normal salinity conditions occurred over currently estuarine back-barrier areas of the Outer Banks of eastern North Carolina during the peak of the Medieval Climate Anomaly. Sedimentary units several meters thick, containing foraminiferal assemblages usually found on the continental shelf of North Carolina, are present in 16 vibracores acquired from the shallow shoals of Pamlico Sound behind Cape Hatteras. Optically stimulated luminescence age estimates from these normal salinity units range from approximately 1360 to 980 calibrated years (cal yr) BP, corresponding with a previously documented collapse of a segment of the southern Outer Banks. It is vital to understand past scenarios of barrier island formation and segmentation to provide insight on how these islands may react to future change in climate and sea level.

Idaszkin, Y.L.; Bortolus, A., and Bouza, P.J., 2014. Flooding effect on the distribution of native austral cordgrass Spartina densiflora in Patagonian salt marshes.

Plant zonation is one of the most conspicuous ecological features of salt marshes worldwide. In Patagonian salt marshes the cordgrass Spartina alterniflora forms dense monospecific stands along the lowest marsh level, while the higher levels are dominated by Spartina densiflora or Sarcocornia perennis. In this study, we coupled field transplants combined with neighbor exclusion treatments and greenhouse experiments to evaluate the effect of submersion and waterlogged anoxic soil in the determination of the lower distribution limit of S. densiflora in Central Patagonian salt marshes within its native range. In the field experiment, no S. densiflora survived the frequent tidal submersion by approximately 2 m of seawater in the low marsh, independent of the S. alterniflora neighbor's presence, while in the greenhouse experiment, all plants were able to tolerate strongly reducing soil conditions. Our results suggest that the absence of S. densiflora in the low marsh level is a consequence of the effect of the submersion, independent of the presence of S. alterniflora neighbors and of the strong soil anoxia. Our results contribute to optimize the efforts addressed to control or eradicate this exotic species in salt marshes where it is invading.

Dzwonkowski, B.; Wong, K.-C., and Ullman, W.J., 2014. Water level and velocity characteristics of a salt marsh channel in the Murderkill estuary, Delaware.

High-frequency observations of water level and velocity over one year in Murderkill estuary, a tributary estuary of Delaware Bay, are used to examine changes in tidal and subtidal flow characteristics as water propagates from the mouth of the estuary (Bowers site) into a minor channel that connects to a contiguous salt marsh (channel site), a setting where long-term continuous data sets are uncommon. These data provide insight into the flow behavior in marsh channels, the driving mechanisms of water exchange, and the potential for particle and solute exchange between tidal marshes and their adjacent estuaries. At both sites, tidal forcing is normally the dominant driving mechanism in water level and velocity signals with remote wind forcing having a limited contribution. As the tidal signal propagates from the Bowers site into the salt marsh, however, the progressive-type mixed wave is transformed into a standing wave with minor velocity distortions resulting from a reduction in the M2 tidal constituent as well as an amplification of the M4 overtide. The variability at both sites is typically well explained as a linear superposition of high-frequency tidal constituents and remotely forced wind-driven subtidal fluctuations. During storm events at intermediate to spring tides, however, both tidal and subtidal velocity characteristics in the channel are more nonlinear compared to both typical channel conditions and those at the Bowers site. During these events, in response to remote winds, tidal flow in the channel becomes progressive in form and flood dominant, while subtidal velocities are ebbward and nearly an order of magnitude stronger than typical conditions.

Batayneh, A.; Zaman, H.; Zumlot, T.; Ghrefat, H.; Mogren, S.; Nazzal, Y.; Elawadi, E.; Qaisy, S.; Bahkaly, I., and Al-Taani, A., 2014. Hydrochemical facies and ionic ratios of the coastal groundwater aquifer of Saudi Gulf of Aqaba: implication for seawater intrusion.

It is now fairly documented that major ion chemistry of the groundwater can be used to determine an interaction between the groundwater and saline water in the costal aquifers, and that there exists a relationship between total dissolved solids and Cl⁻, Na⁺, Mg²⁺, and concentrations of groundwater. This hypothesis is tested on an aquifer located along the Saudi Gulf of Aqaba coast (Red Sea). Groundwater samples collected from 23 locations show the abundance of ions in the order of: Ca²⁺ > Na⁺ > Mg²⁺ > K⁺ = Cl⁻ > > > . The Piper trilinear diagram reveals two dominant clusters, i.e. the Ca²⁺–Cl⁻– facies and the Na⁺–Cl⁻– facies. Besides the major chemical compositions, ionic ratios ( /Cl⁻, Na⁺/Ca²⁺, Na⁺/Cl⁻, Ca²⁺/Cl⁻, Mg²⁺/Cl⁻, K⁺/Cl⁻, /Cl⁻, Ca²⁺/Mg²⁺, Ca²⁺/ , and Ca²⁺/ ) are used to evaluate the effects of saline water intrusions. Factor analysis of the studied samples demonstrates that changes in the groundwater composition are primarily controlled by mineral dissolution, human activities, weathering of marine sediments, evaporation/salinization of groundwater, and the residence time of water. An attempt has been made to identify hydrochemical processes accompanied with the current intrusion of seawater through the use of ionic exchanges. Following this procedure, about 7.97% mixing rate of seawater intrusion has been estimated for the month of March 2012. Furthermore, the seawater mixing index has also been applied, which resulted in a range of values from 0.395 to 7.922. These results determine 13 of 23 groundwater samples (57%) as saline, with electrical conductivity > 3000 μS/cm.

Stanley, J.-D. and Clemente, P.L., 2014. Clay distributions, grain sizes, sediment thicknesses, and compaction rates to interpret subsidence in Egypt's northern Nile Delta.

This study focuses on the role of clay on subsidence of Holocene sedimentary sequences in the northern Nile Delta. Proportions of clay in 1262 samples from 87 cores are much higher here than elsewhere in the delta and along the Nile in Egypt. The northern third of the delta lies at a low, near-horizontal elevation (∼1 m above mean sea level), but clay content and total thickness of Holocene deposits in subsurface vary considerably in time and space. Greatest clay content (to >60%) and mud-rich thickness (to 47 m) are concentrated near Manzala lagoon. The volume of Nile water and sediment discharged annually on the delta diminished during the past two millennia as a result of climate change and intensified human activity. During the past two centuries, barrages and dams placed across the Nile and increased water diversion activities further reduced Nile flow and sediment delivery to the northern delta. Lowering at the coastal margin has also resulted from interplay of sediment compaction, regional sea-level rise, and intermittent readjustment of strata at depth. These events are ongoing, as indicated by increased erosion of extensive stretches of delta coast, salinization that affects large areas of agricultural land and groundwater, and major changes in recent sediment textural patterns as mapped in the present survey. Formerly dominant fluvial S-to-N transport during much of the Holocene has become distinctly shore parallel, recording landward shoreline advance and W-to-E sediment displacement along the delta margin. Implementing extensive coastal protective measures should take into account zones most prone to effects of subsidence, where (1) clay-rich subsurface sequences are thickest, (2) these strata are subject to high compaction rates, (3) sediment replenishment is insufficient, and (4) readjustment at depth of pre-Holocene sequences is continuing. These factors will cause the delta's NE and north-central sectors to experience continued significant surface lowering.

Rouf, M.A. and Nakaza, E., 2014. Seasonal behavior of the internal tide and associated water temperature in Genka Bay, Okinawa, Japan.

Sustainability of coastal aquatic resources is deeply associated with several hydrophysical processes, where internal tide is one of the key processes. Seasonal variation in the characteristics of the internal tidal currents and their associated change in water temperature was observed to take part in managing the coastal aquatic systems in Genka Bay, Okinawa, Japan. Profiling and mooring measurements were carried out in three sites of the study area during summer and winter. The study results show that the depth-averaged current flows nearly parallel to the coastline during summer and winter. There is also an existence of a cross-shore internal tidal current according to the vertical structure of the horizontal current in both seasons. This current influences the bottom water temperature transmission from offshore to nearshore bottom water and changes the vertical temperature profile even of nearshore regions and thereby establishes a unique cooling system. This influence is stronger in summer than in winter due to the seasonal variations in the intensity of the propagated internal tidal currents. Spectra of the baroclinic and bottom water temperature confirm the existence of the semidiurnal constituent-dominated internal tides as well as their seasonal and shoreward variations in Genka Bay.

Feagin, R.A.; Williams, A.M.; Popescu, S.; Stukey, J., and Washington-Allen, R.A., 2014. The use of terrestrial laser scanning (TLS) in dune ecosystems: the lessons learned.

This paper presents a methodology for using terrestrial laser scanning (TLS) to quantify sand dune geomorphology. As an example of the use of TLS, we present methods that were used to investigate changes in sediment and vegetation volumes after Hurricane Ike. We collected TLS data within a 100 m × 100 m plot on the East Matagorda Peninsula, Texas, from early September 2008 (before landfall) to early October 2009 (a year after landfall). Terrestrial laser scanning-collected laser point clouds were then interpolated into several grid sizes. From several interpolated grid sizes, 0.50 m × 0.50 m grids were determined best for analysis as they were able to compromise two competing resolution-related issues: gaps caused by vegetation shadows and the natural contours of the dune. We outline several additional lessons to aid coastal researchers in strengthening their own future work: the use of reference survey stakes in an unstable environment, the development of a novel method to test for errors in point cloud registration among multiple dates, how best to interpret sediment and vegetation change analysis as derived from interpolated grids, and suggestions for incorporating mass-based sedimentary and biomass-based vegetation field studies within the volumetric context of TLS analysis.

Liu, H.; Takagawa, T., and Sato, S., 2014. Sand transport and sedimentary features based on feldspar thermoluminescence: a synthesis of the Tenryu–Enshunada fluvial system, Japan.

On the basis of the feldspar thermoluminescence (TL) measurement, sediment transport features were investigated in the entire Tenryu River watershed and the corresponding littoral sediment zone of the Enshunada coast. Subsequently, the sedimentary configuration and sand provenance in the river mouth area were studied using subsurface samples. In the Tenryu River watershed, TL intensities of the riverine samples fluctuated with respect to the local geological characteristics. Comparing with samples collected from the main river route, branch samples generally present larger TL intensities. Nevertheless, sediment supply from branches is considered to be rather limited in terms of their small discharges. Increase in the riverine TL property can be detected in the immediate dam downstream area, as well as the region with mass sand movements. Taking into account the Enshunada coastal samples, measured sediment TL intensities present a local peak value around the river mouth and a decreasing trend with the increasing distance away from the river mouth. This is attributed to the river sand supply and the gradual sunlight exposure during the longshore sediment transport. In general, riverine samples present much larger TL intensities than coastal samples, and a criterion on the basis of a TL intensity value of 5 was recognized to distinguish these two types of sands in the study area. Applying this criterion to the subsurface samples collected in the river mouth sand spit, a sedimentary interface at Tokyo Peil −1 m was confirmed with coastal sands (small TL intensity with wave experience) located on the top and riverine sands (large TL intensity without wave experience) deposited at the bottom, which is in agreement with estimations from other physical and geomorphological approaches.

Reale, F.; Dentale, F.; Pugliese Carratelli, E., and Torrisi, L., 2014. Remote sensing of small-scale storm variations in coastal seas.

Estimating extreme values of significant wave heights (SWH) is a necessity in many branches of coastal science and engineering. Storm intensity, however, is not a smooth varying quantity, but it oscillates with random variations around a generally regular trend; the estimated value of extreme sea states is, therefore, necessarily affected by the sampling time of the available data. This is especially important when making use of synthetic data deriving from weather and wave simulation systems, which artificially smoothen the SWH record history. Active remote sensing provides valuable help to overcome this problem: the work described here very briefly recalls the available satellite SWH and wind measurements and shows how such data may help clarify and reduce a possible cause of error in wave climate evaluation, and especially so along coastal areas.

Yuan, S.; Li, L.; Amini, F., and Tang, H., 2014. Numerical study of turbulence and erosion of an HPTRM-strengthened levee under combined storm surge overflow and wave overtopping.

Combinations of storm surge and extreme waves may cause overtopping of coastal protection of structures, resulting in structural damage and flooding behind these structures. The high turbulence of the overtopping flow is an important factor for soil erosion and may be responsible for the destruction of levees during combined overtopping. The goal of this study was to investigate the turbulence and erosion characteristics of one levee strengthening technique, high-performance turf reinforcement mat, under combined wave overtopping and storm surge overflow. A three-dimensional hydrodynamic and sediment transport model known as ECOMSED has been calibrated and verified with overflow discharge and full-scale overtopping experimental results. The study simulated 41 storm surge overflow and combined overtopping cases with different freeboards and significant wave heights. Overtopping hydrodynamic flow, turbulent shear stress, turbulent kinetic energy, and erosion rate at the toe of a landside slope under combined overtopping conditions were calculated. New equations for estimating turbulent shear stress, turbulent kinetic energy, and erosion rate at the toe of a landside slope were developed. The equivalency of erosion rate under storm surge overflow and combined wave and surge overtopping are provided. The range of the application of these equations is discussed.

Gorokhovich, Y.; Leiserowitz, A., and Dugan, D., 2014. Integrating Coastal Vulnerability and Community-Based Subsistence Resource Mapping in Northwest Alaska.

Subsistence resources are critical for indigenous communities in the Kotzebue Sound region of NW Alaska. Global sea-level rise (SLR) and coastal erosion are likely to create unfavorable and hazardous conditions for coastal and estuarine settlements. It is unclear how SLR and erosion might affect coastal subsistence resources because of highly complex ecological interactions. This study integrates physical, anthropological, and survey data to assess coastal vulnerability and to identify areas of concern for local and regional planning and environmental protection. This study analyzes and integrates historical and projected physical coastal changes within the Kotzebue Sound region with (1) a coastal vulnerability index (CVI); (2) community-based participatory GIS maps of community subsistence resources; and (3) representative surveys of local communities to determine the importance of each type of resource. The results identify Kivalina and Deering as particularly vulnerable coastal locations among four studied villages. While the CVI is high in these locations, low erosion rates will not likely have any negative impact on fish and caribou—two of the most important subsistence resource species for these communities. Because of the higher number of identified subsistence resource species, Deering is more resilient than Kivalina to any potential negative coastal impacts. This methodology can be useful in other coastal areas where subsistence resources play a major part in people's lives.

Zhang, W; Du, J; Zheng, J; Wei, X., and Zhu, Y. 2014. Redistribution of the suspended sediment at the apex bifurcation in the Pearl River network, South China.

Bifurcations in tidal networks strongly control the distribution of flow and sediment flux over a river network system. These distributions are important in determining the fluvial sediment dispersal and transport from river networks to shorelines, thereby greatly affecting river channel, estuary, and coastal environments. Long-term observations of flow and suspended sediment division at the apex bifurcation of the Pearl River network indicate that there has obviously been more water and sediment transport into the North River network since the 1990s. Wavelet analyses of the sediment division at the apex bifurcation show that common spectral structures were dominated by annual fluctuations from 1959 to 2005. However, significant, intra-annual and annual fluctuations have been detected since the early 1990s, corresponding well with the abrupt changes in flow and sediment division. By analyzing the controlling factors (water discharge ratio η_L and suspended-sediment concentration ratio K_S) of the suspended-sediment flux distribution in a braided river, we concluded that both the riverbed downcutting from intensive sand mining in the lower river and the lack of suspended-sediment supply because of dam construction in the upper river are primarily responsible for the sediment redistribution in the apex bifurcation of the Pearl River delta. Furthermore, the wavelet analysis indicates an energy growth in the signal of the suspended-sediment division ratio. The observed spectral composition was used to estimate the potential suspended-sediment division in the absence of human influences by removing the effect of that energy growth, which helped to explain the extent of the effect of intensive anthropogenic activities on the redistribution of suspended-sediment flux. The estimate indicates that there has been a decrease of 6.27 × 10⁷ tons of suspended-sediment load flowing to the West River network for sediment redistribution at the apex bifurcation of the Pearl River delta between 1992 and 2005.

Ferrari, M.; Cabella, R.; Berriolo, G., and Montefalcone, M., 2014. Gravel sediment bypass between contiguous littoral cells in the NW Mediterranean Sea.

The efficiency of a rocky headland in delimiting littoral cells and preventing sediment bypass was investigated in a coastal area of Liguria (Italy, NW Mediterranean). This area harbours two contiguous pocket beaches separated by a headland that can be considered as a geomorphic and hydrodynamic limit of two littoral cells. Surveys using a single-beam echo sounder were carried out in order to update historical data on the morphology and hydrodynamics of the area. Sediment samples were collected from the foreshore and the nearshore in two pocket beaches, and sediment (including gravel) transport patterns around the headland were described. Distribution and state of health of the endemic seagrass Posidonia oceanica were assessed in order to explore potential links among sediment transport, hydrodynamics, and meadow development. A rip current transporting sediments with an updrift origin to the downdrift beach was evidenced, causing gravel sediment bypass between the two contiguous littoral cells. The direction followed by the rip current was largely influenced by the P. oceanica meadow, which hindered its flow towards the open sea. The shape of sediments and their grain size have been shown to play a significant role in the sediment transport patterns around the rocky headland.

L'efficienza di un promontorio nel delimitare celle litorali è stata analizzata in un area costiera della Liguria (Italia, Mediterraneo nord-occidentale). L'area di studio è caratterizzata da una costa alta rocciosa dove sono presenti due pocket beach separate da un promontorio, che può essere quindi considerato come il limite geomorfologico ed idrodinamico delle due celle litorali. Sono stati effettuati rilevamenti mediante ecoscandaglio al fine di rivedere i dati storici disponibili sulla morfologia e l'idrodinamica dell'area di studio. Campioni di sedimento sono stati raccolti lungo la parte emersa e sommersa delle due pocket beaches ed i pattern di trasporto dei sedimenti (incluse le ghiaie) attorno al promontorio sono stati descritti. La morfologia e lo stato di salute della prateria della fanerogama marina endemica Posidonia oceanica sono stati determinati al fine di esplorare i potenziali legami esistenti tra il trasporto dei sedimenti e la presenza della prateria. I risultati hanno evidenziato la presenza di una rip current in grado di trasportare sedimenti provenienti dalla spiaggia sopraflutto verso la spiaggia sottoflutto, causando così un passaggio di sedimenti, anche di maggiore granulometria, tra le due celle litorali. La direzione seguita dalla rip current è influenzata dalla presenza della prateria di P. oceanica, che non permette alla corrente di fluire verso il largo. La forma dei sedimenti, così come la loro granulometria media, giocano quindi un ruolo fondamentale nella dinamica litoranea dei sedimenti attorno al promontorio.

Yang, Q.; Zhou, L.; Tian, J., and Zhao, W., 2014. The roles of Kuroshio intrusion and mesoscale eddy in upper mixing in the northern South China Sea.

Upper mixing in the northern South China Sea (SCS) is derived from Argo profiles from 2006 to 2012, using the Gregg-Henyey-Polzin parameterization. Temporal and spatial mean estimates reveal clear spatial patterns of mixing over the northern SCS. Enhanced diffusivity on an order of 10⁻³ m² s⁻¹ exists in the Luzon Strait and adjacent areas. South of 20° N, diffusivity is one order of magnitude smaller on average than it is near the Luzon Strait. Such observations suggest that other than internal tides, both Kuroshio intrusion and mesoscale eddy might be key factors to the enhanced mixing. Shear instability associated with Kuroshio intrusion plays a major role in strengthening the turbulent mixing near the Luzon Strait. In addition, warm eddies could reinforce the downward-propagating near-inertial waves and thus promote the occurrence of strong mixing, whereas cold eddies could reduce this downward-propagating, inhibiting strong mixing. This work facilitates the contributions of mesoscale eddy and Kuroshio intrusion in the northern SCS.

Lonard, R.I.; Judd, F.W., and Stalter, R., 2014. The biological flora of coastal dunes and wetlands: Distichlis littoralis (Engelm.) H.L. Bell & Columbus.

Distichlis littoralis (Engelm.) H.L. Bell & Columbus = Monanthochloë littoralis Engelm. is a New World temperate- and subtropical-zone perennial grass that is an important species in hypersaline coastal landscapes. Also known as shoregrass, it tolerates salinities twice that of seawater. It occurs in soils low in organic matter and deficient in nitrogen, phosphorus, and potassium. Dense, monotypic populations of D. littoralis eliminate nearly all competing annuals in harsh coastal habitats. Distichlis littoralis provides limited cover and limited nutrition for resident and migratory birds.

Sinclair, A., 2014. FlowRider: a Lagrangian float to measure 3-D dynamics of plunging breakers in the surf zone.

A very small and low-cost Lagrangian Float, the FlowRider, was developed to measure three-dimensional (3-D) free-surface accelerations and dynamics of plunging breakers and is described here. The FlowRider is equipped with a microelectromechanical systems inertial measurement unit, small enough to be deployed by one person in a laboratory wave tank or the surf zone, and is durable in both deployment environments. Free-surface accelerations of plunging breakers were measured by the FlowRider during a field experiment at Waimea Bay, Oahu, Hawaii. For wave heights greater than 0.3 m, the data clearly show when the FlowRider travels in a wave, is in free fall, and impacts the water surface below. Maximum free-surface accelerations measured exceed 8 g. The FlowRider represents a novel, low-cost instrument solution to obtain in situ measurements of 3-D dynamics of plunging breakers.

Dragani, W.C.; D'Onofrio, E.; Alonso, G.; Fiore, M., and Oreiro, F., 2014. Sea-level trend at the southernmost region of South America.

Tide gauge data were used to estimate the sea-level trend at the Ushuaia tidal station (54°49′ S, 68°13′ W), located at the southernmost city in the world. The Ushuaia tidal station began working in 1951 but was relocated in 1970 approximately 900 m from its original location. Special care was taken in linking both data series to compose a single and reliable sea-level record gathered from 1952 to 2005. The least-square regression line for annual mean sea level (relative to the benchmark) was fitted, and the computed slope that resulted was not significantly different from zero. A low-pass filter was applied to the annual sea-level data series to smooth the constituents of tide longer than 1 year, which could mislead the trend of the mean sea level. The trend of the best fit line computed from the filtered data was −0.2 mm y⁻¹, which was not significantly different from zero. Taking into account the Peltier glacial isostatic adjustment prediction, a corrected sea-level trend was estimated in 1 mm y⁻¹ for the Ushuaia tidal station. The sea-level trend was also estimated by processing the altimetry data series gathered at five satellite track crossings located in the adjacent ocean (analyzed period 1992–2011). Resulting sea-level trends computed from altimetry data presented high spatial variability (from −0.9 to 3.1 mm y⁻¹), which is likely associated with the rather short length of the processed data series. The authors of this technical communication foresee that these results will contribute to our knowledge of sea-level change in the Southern Hemisphere, especially southward of 50°S, where long sea-level data series are considerably scarce.