scholarly journals Natural and Anthropogenic Variations in the Large Shifting Dune in the Corrubedo Natural Park, NW Iberian Peninsula (1956–2017)

2020 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Augusto Pérez-Alberti ◽  
Alejandro Gómez-Pazo ◽  
X. L. Otero
Keyword(s):  
Aerial Images ◽  
Light Detection And Ranging ◽  
Dune System ◽  
The North ◽  
Natural Park ◽  
Geostatistical Techniques ◽  
Anthropic Influence ◽  
Mobile Dune ◽  
Topographic Surveys ◽  
Sand Extraction

This work analyzes the evolution of the large shifting dune included in the Corrubedo Natural Park from 1956 until the present day. The analysis was carried out using aerial images, orthophotographs, topographic surveys and LiDAR (Light Detection and Ranging) data. Variations were analyzed in terms of four different aspects: evolution of pathways in each period, changes in the position of the mobile dune front and the degree of vegetation cover, all between 1956 and 2017; and variations in elevation and volume of the dune system between 2001 and 2015. To analyze these aspects, geospatial and geostatistical techniques were employed, which revealed that the dune front had undergone two different phases: one until the 1980s, with a mean seaward advance of 32 m and another one between the 1980 s and 2017, when the front prograded to the continent, with an approximate mean advance of 82 m. Loss of volume, related to the expansion of the mobile dune towards the north, was confirmed in this sector. It is evident that these changes are closely linked to anthropic influence, due to sand extraction until the early 1990s and, more recently, due to an increase in the number of visitors to the Natural Park. The results obtained highlight the need to carry out detailed studies to understand the evolution of this system and to prevent further damage in the future. Moreover, based on these analyses, a strategy to improve coastal and environmental management in the Corrubedo Natural Park could be designed.

scholarly journals Recent Evolution (1956–2017) of Rodas Beach on the Cíes Islands, Galicia, NW Spain

2019 ◽  
Vol 7 (5) ◽  
pp. 125 ◽  
Author(s):  
Alejandro Gómez-Pazo ◽  
Augusto Pérez-Alberti ◽  
Xose Lois Otero Pérez
Keyword(s):  
Aerial Images ◽  
Nw Spain ◽  
Dune Vegetation ◽  
Dune System ◽  
Study Zone ◽  
Information System Technology ◽  
Analysis System ◽  
Natural Dynamics ◽  
Port Infrastructure ◽  
Sand Extraction

Sedimentary coastal areas change rapidly and are economically and environmentally important. This research focuses on determining the extent to which natural dynamics and human activity have contributed to visible changes on Rodas, Cíes Islands in southwestern Galicia (NW Spain). The number of visitors to the islands has increased in recent years, and the port infrastructure has therefore been expanded. Previously, this zone experimented with important sand extraction phases. These changes have influenced the ecosystem directly by modifying the sedimentary behavior and indirectly by promoting even greater numbers of visitors to the area. Aerial images and orthophotographs of the study zone were examined to identify changes that have taken place over the last sixty-one years (1956–2017). Changes in the position of the shoreline, defined as the boundary of the dune vegetation, were mapped at different times between 1956 and 2017. Changes in the shoreline were quantified using GIS (Geographic Information System) technology and Digital Shoreline Analysis System (DSAS) software. The findings revealed that the system regressed by more than 30 m between 1956 and 1981, in part as a result of sand extraction. We also identified different erosion/accretion phases that occurred before the reformation of the Rodas dock in 2010. The system is currently undergoing important changes, especially in the northern area, with a regression of 14.14 m in the last seven years. In this context, LiDAR analysis from 2010 and 2015 using Geomorphic Change Detection (GCD) tools allowed variations in the dune system to be verified. The elevation in the study zone increased in 83% of the area, mainly in the frontal dune and close to the winter inlet (north sector). However, the variations were very small.

Subglacial topography and thickness of ice caps on the Argentine Islands

2019 ◽  
Vol 31 (6) ◽  
pp. 332-344 ◽  
Author(s):  
Jānis Karušs ◽  
Kristaps Lamsters ◽  
Anatolii Chernov ◽  
Māris Krievāns ◽  
Jurijs Ješkins
Keyword(s):  
Land Surface ◽  
Geological Structure ◽  
Aerial Images ◽  
Ice Thickness ◽  
Ice Caps ◽  
The North ◽  
Prevailing Wind Direction ◽  
Aerial Vehicle ◽  
Subglacial Topography ◽  
Ground Penetrating

AbstractThis study presents the first subglacial topography and ice thickness models of the largest ice caps of the Argentine Islands, Wilhelm Archipelago, West Antarctica. During this study, ground-penetrating radar was used to map the thickness and inner structure of the ice caps. Digital surface models of all studied islands were created from aerial images obtained with a small-sized unmanned aerial vehicle and used for the construction of subglacial topography models. Ice caps of the Argentine Islands cover ~50% of the land surface of the islands on average. The maximum thickness of only two islands (Galindez and Skua) exceeds 30 m, while the average thickness of all islands is only ~5 m. The maximum ice thickness reaches 35.3 m on Galindez Island. The ice thickness and glacier distribution are mainly governed by prevailing wind direction from the north. This has created the prominent narrow ice ridges on Uruguay and Irizar islands, which are not supported by topographic obstacles, as well as the elongated shape of other ice caps. The subglacial topography of the ice caps is undulated and mainly dependent on the geological structure and composition of magmatic rocks.

scholarly journals Ice Conditions of an Arctic Polynya: North Water in Winter

1986 ◽  
Vol 32 (112) ◽  
pp. 383-390 ◽  
Author(s):  
Konrad Steffen
Keyword(s):  
Sea Water ◽  
Surface Condition ◽  
Open Water ◽  
Sea Surface ◽  
Aerial Images ◽  
The Arctic ◽  
The North ◽  
North Water ◽  
Ice Conditions ◽  
Fast Ice

AbstractThe surface condition of the North Water was investigated during two winters (i.e. the three polynyas: Smith Sound polynya, Lady Ann Strait polynya, and Barrow Strait polynya). Since no detailed information was available on ice conditions and the extent of open water during winter, radiometric temperature measurements of the sea surface had to be taken along a flight line of 2650 km from an altitude of 300 m. From November to March 1978-79 and 1980-81, 14 remote-sensing flights were carried out. On the basis of the radiometric measurements, the following ice types were identified: ice-free, dark nilas, light nilas, grey ice, grey-white ice, and white ice. A comparison between the thermal and the visual ice classification (the latter being based on grey tones of the aerial images) showed a deviation of 3%. The analysis showed that in November, December, and January more than 50% of the Smith Sound polynya was covered by young ice, nilas, and ice-free, whereas in February and March white ice was dominant. Moreover, it was found that the two polynyas in Smith Sound and Lady Ann Strait were much smaller than previously believed. In Barrow Strait, a semi-permanent polynya was observed in the winter of 1980-81. The occurrence of polynyas in Barrow Strait seems to be connected with the location of the fast-ice edge. On the basis of the calculated ice-type distribution and heat-flux rates for different ice types, an energy loss of 178 W m-2was found on the surface of the Smith Sound polynya due to open water and thin ice for the winter months November to March. Compared with other ice-covered sea surfaces in the Arctic, the heat release by the sea-water in the Smith Sound polynya is about 100 W m-2larger.

scholarly journals AN IDEALIZED MODEL OF TIDAL DYNAMICS IN SEMI-ENCLOSED BASINS: THE EFFECTS OF A MEGA-SCALE SAND EXTRACTION TRENCH IN THE NORTH SEA

2011 ◽  
Vol 1 (32) ◽  
pp. 37
Author(s):  
Wiebe P De Boer ◽  
Pieter C Roos ◽  
Suzanne J M H Hulscher ◽  
Ad Stolk
Keyword(s):  
North Sea ◽  
Classical Problem ◽  
Tidal Range ◽  
Kelvin Wave ◽  
Tidal Dynamics ◽  
Coastal Morphology ◽  
Idealized Model ◽  
The North ◽  
Order Of Magnitude ◽  
Sand Extraction

We investigate the effects of a mega-scale sand extraction trench (length ~200 km, width ~10 km, depth ~10 m, located in front of the Dutch coast) on tidal dynamics in the Southern North Sea. To this end, an idealized modeling approach is adopted, extending the classical problem of Kelvin wave reflection in rectangular semi-enclosed basins to account for lateral depth variations and the presence of a trench. The model results indicate changes in tidal range (zones of decrease and increase of the order of several cm), phase and currents (order cm/s) throughout the whole basin, which emphasizes the importance of a model domain on the scale of the basin. The changes in currents may structurally change sediment transport rates by several percents, which is relevant to coastal morphology. It is argued that this idealized model can be used to support a companion study carried out with a more detailed numerical engineering model. This is because of its ability to (1) provide insight into the physical mechanisms, (2) reveal the order of magnitude and area of influence of the effects and (3) allow for a quick sensitivity analysis with respect to trench geometry.

scholarly journals GEOLOGICAL-GEOMORPHOLOGICAL ANALYSIS OF NATIONAL NATURAL PARKS OF THE NORTH-WESTERN PART OF THE UKRAINIAN CARPATHIANS

2021 ◽  
pp. 184-207
Author(s):  
Yaroslav Kravchuk ◽  
Vitaliy Brusak
Keyword(s):  
National Parks ◽  
Geological Structure ◽  
Mountain Ranges ◽  
The North ◽  
Natural Park ◽  
Natural Parks ◽  
Different Ages ◽  
Gravitational Processes ◽  
River Valleys ◽  
North Western

In the stydy an analysis of the geological structure and relief of Uzhansky, “Skolivsky Beskydy”, and “Boykivshchyna” national natural parks (NNP), located in the north-western part of the Ukrainian Carpathians, is presented. Uzhansky NNP is located within the Polonynsko-Chornohirska and Vododilno-Verkhovyna geomorphological regions, “Skolivski Beskydy” NNP is situated in the Skibovy Carpathians, and the newly created “Boykivshchyna” NNP is located within the Vododilno-Verkhovyna and Skybovi Carpathians. The analysis of the morphostructure and morphosculpture of national parks is carried out taking into account the longitudinal (N-W–S-E) and transverse divisions of the Ukrainian Carpathians. The longitudinal division is associated with higher morphostructures of higher orders – the second and third, with the transverse is associated with the fourth and fifth morphostructures. In the analysis of morphosculpture of national parks, the types which are characteristic of the Carpathian Flysch belt are allocated. All mountain ranges and ridges are characterized by an asymmetrical structure – steep northeastern slopes and declivous southwestern slopes. The relic morphosculpture is represented by: 1) fragments of denudation surfaces of different ages such as Beskid, Pidbeskid, and riparian; 2) extra glacial and firn glaciations; 3) areas of ancient longitudinal valleys. Inherited morphosculpture is represented by river valleys with a complex of terraces of different ages. Modern morphodynamic processes represent by height (tier) differentiation. In the tiers of strongly dissected mid-mountain and low-mountain relief, the processes of planar erosion, deflux, and linear erosion play an important role in the modeling of the relief. The lower tier of the terraced and non-terraced bottoms of the valleys are associated with the processes of leaching and erosion as well as a significant accumulation of erosion products and mudflows. Among gravitational processes and block motions, stabilized and active displacements are the most recorded. Keywords: National natural park; Ukrainian Carpathians; relief; morphostructure; morphosculpture.

scholarly journals Caracterização da Cobertura Vegetal no Alto Curso da Bacia do Igarapé do Mindu - Manaus (AM)

2020 ◽  
Vol 13 (1) ◽  
pp. 406
Author(s):  
Natalia Ramos Albuquerque ◽  
Deivison Carvalho Molinari
Keyword(s):  
Global Position System ◽  
Vegetation Cover ◽  
Aerial Images ◽  
Position System ◽  
Vegetation Coverage ◽  
Partial Replacement ◽  
Forest Fragment ◽  
The North ◽  
Environmental Protection Area ◽  
Protection Area

O processo urbano acelerado ao longo dos anos dentro da cidade de Manaus - AM acabou ocasionando substituição parcial da cobertura vegetal por ocupações irregulares. Deste modo, o objetivo deste estudo é analisar o tipo de cobertura vegetal presente no alto curso da bacia hidrográfica do igarapé do Mindu, localizado entre a zona norte e leste da área urbana de Manaus - Amazonas. A metodologia do trabalho baseou-se em três etapas: pré-campo realizada mediante técnicas de geoprocessamento para identificação da área de estudo via  Qgis, monitoramento do trabalho de campo registrada por fotografias com auxílio do GPS (Global Position System), uso de VANT para adquirir imagens aéreas de alta resolução espacial, e o pós-campo resultando no processamentos das imagens e análise dos dados. Os resultados encontrados demostram concentração de espécies concentradas ao norte da bacia procurando identificar a distribuição e caracterização das espécies vegetais do tipo: Unidade de Conservação, Áreas Verdes, Fragmento Florestal, Área de Proteção Permanente (APP), Área de Proteção Ambiental (APA) e Corredor Ecológico.Characterization of Vegetation Coverage in the Upper Course of the Igarapé do Mindu Basin - Manaus (AM)A B S T R A C TThe accelerated urban process over the years within the city of Manaus - AM eventually led to partial replacement of vegetation cover by irregular occupations. Thus, the aim of this study is to analyze the type of vegetation cover present in the upper reaches of the Mindu stream, located between the north and east of the urban area of Manaus - Amazonas. The methodology of the work was based on three steps: pre-field carried out by geoprocessing techniques to identify the study area via Qgis, fieldwork monitoring recorded by photographs with the aid of GPS (Global Position System), use of UAV for acquire high spatial resolution aerial images, and the postfield resulting in image processing and data analysis. The results show a concentration of species concentrated to the north of the basin, seeking to identify the distribution and characterization of plant species such as: Conservation Unit, Green Areas, Forest Fragment, Permanent Protection Area (APP), Environmental Protection Area (APA) and Ecological corridor.Keywords: radiation, net radiation, photosynthetically active radiation, Caatinga, dry.

scholarly journals Climate change and outbreaks of amphibian chytridiomycosis in a montane area of Central Spain; is there a link?

2006 ◽  
Vol 274 (1607) ◽  
pp. 253-260 ◽  
Author(s):  
Jaime Bosch ◽  
Luís M Carrascal ◽  
Luis Durán ◽  
Susan Walker ◽  
Matthew C Fisher
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Batrachochytrium Dendrobatidis ◽  
Global Scale ◽  
Amphibian Species ◽  
The North ◽  
Natural Park ◽  
Circulation Patterns ◽  
The North Atlantic Oscillation

Amphibian species are declining at an alarming rate on a global scale in large part owing to an infectious disease caused by the chytridiomycete fungus, Batrachochytrium dendrobatidis . This disease of amphibians has recently emerged within Europe, but knowledge of its effects on amphibian assemblages remains poor. Importantly, little is known about the environmental envelope that is associated with chytridiomycosis in Europe and the potential for climate change to drive future disease dynamics. Here, we use long-term observations on amphibian population dynamics in the Peñalara Natural Park, Spain, to investigate the link between climate change and chytridiomycosis. Our analysis shows a significant association between change in local climatic variables and the occurrence of chytridiomycosis within this region. Specifically, we show that rising temperature is linked to the occurrence of chytrid-related disease, consistent with the chytrid-thermal-optimum hypothesis. We show that these local variables are driven by general circulation patterns, principally the North Atlantic Oscillation. Given that B. dendrobatidis is known to be broadly distributed across Europe, there is now an urgent need to assess the generality of our finding and determine whether climate-driven epidemics may be expected to impact on amphibian species across the wider region.

UAV surveys illuminate the morpho-structural and volume changes from the 2019 paroxysmal eruptions of Stromboli volcano (Italy)

2020 ◽  
Author(s):  
Emanuela De Beni ◽  
Daniele Andronico ◽  
Massimo Cantarero ◽  
Riccardo Civico ◽  
Elisabetta Del Bello ◽  
...  
Keyword(s):  
Structural Changes ◽  
Risk Mitigation ◽  
Morphological Changes ◽  
Pyroclastic Flows ◽  
Aerial Images ◽  
Stromboli Volcano ◽  
Morphological Variations ◽  
Southern Sector ◽  
The North ◽  
Elevation Model

<p>Stromboli Volcano was very active in the summer of 2019:  Two paroxysms dramatically changed the summit craters of the volcano on July 3 and August 28. The first intense paroxysmal eruptive sequence involved both the North and the Central-South (C-S) crater areas and has generated an eruptive plume rising 4 km above the summit (924 m a.s.l.) while the incandescent material set fire to vegetation on the flanks of the volcano. Volcanic products from the laterally directed explosions and from the collapse of the external crater terrace generated two pyroclastic flows that travelled down the Sciara del Fuoco (SdF) and for several hundred of meters out to sea. Between July 3 and August 28, the activity was characterised by lava flows in the Southern sector of the SdF and by very intense Strombolian activity at a set of small scoria cones that grew around the vents, particularly in the N crater area. The second paroxysmal eruption occurred on August 28 again involving the two crater areas and producing an eruptive column that rose 4 km above the summit. Material from the eruption and from the collapse of the rim of the C-S area contributed to the generation of a pyroclastic flow that travelled down the SdF and out to sea. Important morphological variations to the crater terrace were evident after the two paroxysms.</p><p>We used UAVs to monitor morpho-structural changes of the Stromboli volcano following the paroxysmal eruptions; in particular, five high-resolution UAV survey campaigns have been performed since May 2019. The aerial images were acquired using two different UAVs, a DJI Mavic 2 Pro and a Wingcopter. Using Structure-from-Motion (SfM) techniques we generated DEMs (Digital Elevation Model) and orthoimages with a resolution ranging between 0.2 and 0.5 m. An additional 1 m-resolution DEM was extracted from available tri-stereo Pleiades satellite imagery and chosen as pre-paroxysm surface. Using the orthoimages it was possible to map the distribution of eruption products and determine the morpho-structural changes. Furthermore, the topographic approach (subtraction between two different surfaces DEMs) with a cut-and-fill procedure was chosen to calculate the volume gain (in the southern sector of the SdF) and loss (in the crater areas).</p><p>This work demonstrates the usefulness of the combined use of UAVs and SfM techniques to map volcanic products, to highlight morphological changes and perform volume estimations. The data collected during these field efforts and the temporal comparisons of the DEMs represent a fundamental contribution to both volcanic hazard assessment and risk mitigation, and can be used to support civil protection operations.</p>

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