Evaluation of ENTLN Performance Characteristics Based on the Ground Truth Natural and Rocket-Triggered Lightning Data Acquired in Florida

The performance characteristics of the Earth Networks Total Lightning Network (ENTLN) were evaluated by using as ground truth natural cloud-to-ground (CG) lightning data acquired at the Lightning Observatory in Gainesville (LOG) and rocket-triggered lightning data obtained at Camp Blanding (CB), Florida, in 2014 and 2015. Two ENTLN processors (data processing algorithms) were evaluated. The old processor (P2014) was put into use in June 2014 and the new one (P2015) has been operational since August 2015. Based on the natural-CG-lightning data set (219 flashes containing 608 strokes), the flash detection efficiency (DE), flash classification accuracy (CA), stroke DE, and stroke CA for the new processor were found to be 99%, 97%, 96%, and 91%, respectively, and the corresponding values for the old processor were 99%, 91%, 97%, and 68%. The stroke DE and stroke CA for first strokes are higher than those for subsequent strokes. Based on the rocket-triggered lightning data set (36 CG flashes containing 175 strokes), the flash DE, flash CA, stroke DE, and stroke CA for the new processor were found to be 100%, 97%, 97%, and 86%, respectively, while the corresponding values for the old processor were 100%, 92%, 97%, and 42%. The median values of location error and absolute peak current estimation error were 215 m and 15% for the new processor, and 205 m and 15% for the old processor. For both natural and triggered CG lightning, strokes with higher peak currents were more likely to be both detected and correctly classified by the ENTLN

Benthic ecology of semi-natural coastal lagoons, in the Ria Formosa (Southern Portugal), Exposed to different water renewal regimes

Several studies in semi-natural coastal lagoons in the Ria Formosa lagoonal system have been carried out. These man-made water reservoirs behave as small lagoons with one opening to the tidal channels, which may be intermittent. Because of their size, these reservoirs are ideal sites for ecological studies. Water quality and macrobenthic fauna were analysed in five water reservoirs. All reservoirs received the same incoming water through a tidal channel, but they differed in water renewal regime. Multidimensional Scaling (MDS) and Discriminant Analysis were used to evaluate the similarity among sites, stations and sampling occasions. Different levels of taxonomic resolution (family, large taxonomic groups and phylum level) were also evaluated. The separation of sites and stations became unclear using high taxonomic levels. Results from the multivariate analyses suggest a slight differentiation of the stations according to sampling occasion but a clear differentiation of the several water reservoirs. Some of the lagoons studied with low water renewal rates showed strong environmental variations. They were characterised by low diversity indexes and abundance of small-sized organisms. Other lagoons, with high water renewal rates, showed low environmental variation and well diversified and structured benthic communities. The main environmental factor that seems to affect the benthic communities was the variation in salinity between neap and spring tides, which is related with the water renewal regime. Coastal lagoons offer a protected shallow habitat, which can be highly productive. Well structured communities, controlled by k-strategists, can develop and settle in leaky lagoons, that is, lagoons with wide entrance channels and tidal currents which guarantee a good water renewal. In these lagoons, biomass can accumulate in large organisms. In contrast, lagoons with a single narrow entrance, that may be closed for long periods, are characterised by persistent physical stress and are dominated by communities of small-sized r-strategists

Sandy coastlines under threat of erosion

Sandy beaches occupy more than one-third of the global coastline(1) and have high socioeconomic value related to recreation, tourism and ecosystem services(2). Beaches are the interface between land and ocean, providing coastal protection from marine storms and cyclones(3). However the presence of sandy beaches cannot be taken for granted, as they are under constant change, driven by meteorological(4,5), geological(6) and anthropogenic factors(1,7). A substantial proportion of the world's sandy coastline is already eroding(1,7), a situation that could be exacerbated by climate change(8,9). Here, we show that ambient trends in shoreline dynamics, combined with coastal recession driven by sea level rise, could result in the near extinction of almost half of the world's sandy beaches by the end of the century. Moderate GHG emission mitigation could prevent 40% of shoreline retreat. Projected shoreline dynamics are dominated by sea level rise for the majority of sandy beaches, but in certain regions the erosive trend is counteracted by accretive ambient shoreline changes; for example, in the Amazon, East and Southeast Asia and the north tropical Pacific. A substantial proportion of the threatened sandy shorelines are in densely populated areas, underlining the need for the design and implementation of effective adaptive measures. Erosion is a major problem facing sandy beaches that will probably worsen with climate change and sea-level rise. Half the world's beaches, many of which are in densely populated areas, could disappear by the end of the century under current trends; mitigation could lessen retreat by 40%.info:eu-repo/semantics/publishedVersio

Oyster Reefs as Natural Breakwaters Mitigate Shoreline Loss and Facilitate Fisheries

Shorelines at the interface of marine, estuarine and terrestrial biomes are among the most degraded and threatened habitats in the coastal zone because of their sensitivity to sea level rise, storms and increased human utilization. Previous efforts to protect shorelines have largely involved constructing bulkheads and seawalls which can detrimentally affect nearshore habitats. Recently, efforts have shifted towards “living shoreline” approaches that include biogenic breakwater reefs. Our study experimentally tested the efficacy of breakwater reefs constructed of oyster shell for protecting eroding coastal shorelines and their effect on nearshore fish and shellfish communities. Along two different stretches of eroding shoreline, we created replicated pairs of subtidal breakwater reefs and established unaltered reference areas as controls. At both sites we measured shoreline and bathymetric change and quantified oyster recruitment, fish and mobile macro-invertebrate abundances. Breakwater reef treatments mitigated shoreline retreat by more than 40% at one site, but overall vegetation retreat and erosion rates were high across all treatments and at both sites. Oyster settlement and subsequent survival were observed at both sites, with mean adult densities reaching more than eighty oysters m−2 at one site. We found the corridor between intertidal marsh and oyster reef breakwaters supported higher abundances and different communities of fishes than control plots without oyster reef habitat. Among the fishes and mobile invertebrates that appeared to be strongly enhanced were several economically-important species. Blue crabs (Callinectes sapidus) were the most clearly enhanced (+297%) by the presence of breakwater reefs, while red drum (Sciaenops ocellatus) (+108%), spotted seatrout (Cynoscion nebulosus) (+88%) and flounder (Paralichthys sp.) (+79%) also benefited. Although the vertical relief of the breakwater reefs was reduced over the course of our study and this compromised the shoreline protection capacity, the observed habitat value demonstrates ecological justification for future, more robust shoreline protection projects

Using Agent-Based Modelling to Inform Policy – What Could Possibly Go Wrong?

© 2019, Springer Nature Switzerland AG. Scientific modelling can make things worse, as in the case of the North Atlantic Cod Fisheries Collapse. Some of these failures have been attributed to the simplicity of the models used compared to what they are trying to model. MultiAgent-Based Simulation (MABS) pushes the boundaries of what can be simulated, prompting many to assume that it can usefully inform policy, even in the face of complexity. That said, MABS also brings with it new difficulties and potential confusions. This paper surveys some of the pitfalls that can arise when MABS analysts try to do this. Researchers who claim (or imply) that MABS can reliably predict are criticised in particular. However, an alternative is suggested – that of using MABS for a kind of uncertainty analysis – identifying some of the possible ways a policy can go wrong (or indeed go right). A fisheries example is given. This alternative may widen, rather than narrow, the range of evidence and possibilities that are considered, which could enrich the policy-making process. We call this Reflexive Possibilistic Modelling

Atlantic Coast Beaches: A Guide to Ripples, Dunes, and Other Natural Features of the Seashore

At first glance, the beach may appear to be an endless, flat, monotone landscape meant only for swimming, snoozing, or working on your tan. Upon closer inspection, though, the beach reveals that it has myriad treasures for the curious to locate, such as ephemeral beach ripples decorating the sand, traces of miniature organisms inscribed on dunes, and armored mudballs. Atlantic Coast Beaches, from Maine to Florida, are full of amazing features formed by the interactions between tides, currents, bedrock, weather, beach critters, and much more. Written for a general audience, Atlantic Coast Beaches: A Guide to Ripples, Dunes, and Other Natural Features of the Seashore covers everything, from microscopic nematodes to the potentially cataclysmic changes occurring along the coastline due to rising sea level. Its clear writing, illustrative photographs, and instructive diagrams answer some curious questions, such as why do some sands bark and sing, how do miniature sand volcanoes form, and how do barrier islands migrate?https://digitalcommons.library.umaine.edu/fac_monographs/1112/thumbnail.jp

The World\u27s Beaches: A Global Guide to the Science of the Shoreline

Take this book to the beach; it will open up a whole new world. Illustrated throughout with color photographs, maps, and graphics, it explores one of the planet’s most dynamic environments—from tourist beaches to Arctic beaches strewn with ice chunks to steaming hot tropical shores. The World’s Beaches tells how beaches work, explains why they vary so much, and shows how dramatic changes can occur on them in a matter of hours. It discusses tides, waves, and wind; the patterns of dunes, washover fans, and wrack lines; and the shape of berms, bars, shell lags, cusps, ripples, and blisters. What is the world’s longest beach? Why do some beaches sing when you walk on them? Why do some have dark rings on their surface and tiny holes scattered far and wide? This fascinating, comprehensive guide also considers the future of beaches, and explains how extensively people have affected them—from coastal engineering to pollution, oil spills, and rising sea levels.https://digitalcommons.library.umaine.edu/fac_monographs/1032/thumbnail.jp