Structure-from-motion photogrammetry analysis of historical aerial photography: Determining beach volumetric change over decadal scales     

Rafael C. Carvalho  David M. Kennedy  Yakufu Niyazi  Chloe Leach  Teresa M. Konlechner  Daniel Ierodiaconou 《地球表面变化过程与地形》2020,45(11):2540-2555

Historical aerial photographs are an invaluable tool in shoreline mapping and change detection in coastal landscapes. We evaluate the extent to which structure-from-motion (SfM) photogrammetric methods can be applied to quantify volumetric changes along sandy beaches, using archival imagery. We demonstrate the application of SfM-derived digital surface models (DSMs) at East Beach and Lady Bay in southwest Victoria, Australia, using photographic datasets taken in 1969, 1977 and 1986, and compare them to LiDAR-derived DSMs acquired at both sites in 2007. The SfM approaches resulted in two entire and two partial suitable DSMs out of six datasets. Good-quality DSMs were spatially continuous with a good spread of ground control points (GCPs) near the beach at Lady Bay, whereas unsuitable DSMs were mostly restricted by poor distribution and number of GCPs in spatially segmented areas of East Beach, due to limited overlapping of images, possible poor quality of GCPs and also the propagation of errors in the derived point clouds. A volume of approximately 223 000 ± 72 000 m³ was deposited at Lady Bay between 1969 and 2007, despite minimal erosion observed near the breakwater. The partially suitable dataset of East Beach indicated that beach erosion of at least 39 m³ m⁻¹ occurred immediately to the east of the seawall after 1977. We also discuss the drawbacks and strengths of SfM approaches as a benchmark of historical erosion assessments along sandy beaches. © 2020 John Wiley & Sons, Ltd.  相似文献   

Area usage estimation and spatiotemporal variability in distribution patterns of southern right whales,Eubalaena australis,of southern Brazil          下载免费PDF全文

Eduardo Pires Renault‐Braga  Karina Rejane Groch  Paulo A. de Carvalho Flores  Eduardo R. Secchi  Luciano Dalla‐Rosa 《Marine Ecology》2018,39(3)

Southern right whales—Eubalaena australis (Desmoulins, 1822)—migrate seasonally from high‐latitude feeding grounds to coastal breeding and calving grounds at lower latitudes such as the southern coast of Brazil. Understanding how these whales are distributed along the coast is important for monitoring their postwhaling recovery and defining management strategies. In this study, we applied Kernel density estimators to aerial survey data to determine main occurrence and concentration areas of right whales in southern Brazil and investigate inter‐ and intra‐annual distribution patterns between 2003 and 2012. Our results show considerable variation in area usage within and among years, and changes in the general distribution pattern of right whales in the last years of the study. Intra‐annually, higher concentration area tended to expand from July to September and decrease in November. Some areas stood out as high‐density areas for right whales: Ribanceira/Ibiraquera, Itapirubá Sul/Sol, and from Arroio to Gaivota. Some evidences also suggest preferential areas for mother–calf pairs. The higher concentration area of right whales in southern Brazil was estimated at 52,541 km² and the occurrence area was 682.69 km², which is the whole study area. As right whale distribution in the region is likely expanding due to this population's current recovery, our study provides essential information for management plan of the Right Whale Environmental Protection Area.  相似文献   

Potential of legacy 2D seismic data for deep targeting and structural imaging at the Neves–Corvo massive sulphide-bearing deposit,Portugal     

George A. Donoso  Alireza Malehmir  Nelson Pacheco  Vitor Araujo  Matthew Penney  Joao Carvalho  Bill Spicer  Steve Beach 《Geophysical Prospecting》2020,68(1):44-61

Seismic methods are becoming an established choice for deep mineral exploration after being extensively tested and employed for the past two decades. To investigate whether the early European mineral-exploration datasets had potential for seismic imaging that was overlooked, we recovered a low-fold legacy seismic dataset from the Neves–Corvo mine site in the Iberian Pyrite Belt in southern Portugal. This dataset comprises six 4–6 km long profiles acquired in 1996 for deep targeting. Using today's industry-scale processing algorithms, the world-class, ca. 150 Mt, Lombador massive sulphide and other smaller deposits were better imaged. Additionally, we also reveal a number of shallow but steeply dipping reflections that were absent in the original processing results. This study highlights that legacy seismic data are valuable and should be revisited regularly to take advantage of new processing algorithms and the experiences gained from processing such data in hard-rock environments elsewhere. Remembering that an initial processing job in hard rock should always aim to first obtain an overall image of the subsurface and make reflections visible, and then subsequent goals of the workflow could be set to, for example understanding relative amplitude ratios. The imaging of the known mineralization implies that this survey could likely have been among one of the pioneer studies in the world that demonstrated the capability of directly imaging massive sulphide deposits using the seismic method.  相似文献   

Assessing shallow landslide hazards using the TRIGRS and SHALSTAB models,Serra do Mar,Brazil     

Bianca Carvalho Vieira  Nelson Ferreira Fernandes  Oswaldo Augusto Filho  Tiago Damas Martins  David R. Montgomery 《Environmental Earth Sciences》2018,77(6):260

The hillslopes of the Serra do Mar, a system of escarpments and mountains that extend more than 1500 km along the southern and southeastern Brazilian coast, are regularly affected by heavy rainfall that generates widespread mass movements, causing large numbers of casualties and economic losses. This paper evaluates the efficiency of susceptibility mapping for shallow translational landslides in one basin in the Serra do Mar, using the physically based landslide susceptibility models SHALSTAB and TRIGRS. Two groups of scenarios were simulated using different geotechnical and hydrological soil parameters, and for each group of scenarios (A and B), three subgroups were created using soil thickness values of 1, 2, and 3 m. Simulation results were compared to the locations of 356 landslide scars from the 1985 event. The susceptibility maps for scenarios A1, A2, and A3 were similar between the models regarding the spatial distribution of susceptibility classes. Changes in soil cohesion and specific weight parameters caused changes in the area of predicted instability in the B scenarios. Both models were effective in predicting areas susceptible to shallow landslides through comparison of areas predicted to be unstable and locations of mapped landslides. Such models can be used to reduce costs or to define potentially unstable areas in regions like the Serra do Mar where field data are costly and difficult to obtain.  相似文献   

The Cabo Frio upwelling overrides geographical patterns in the population dynamics of the shrimp Artemesia longinaris Spence Bate, 1888 (Decapoda: Penaeidae)     

Abner Carvalho‐Batista  Joo Alberto Farinelli Pantaleo  Antonio Leo Castilho  Rogrio Caetano da Costa 《Marine Ecology》2019,40(2)

Upwelling areas are among the most productive ecosystems on the planet, influencing the biology of marine organisms. This study investigated the population dynamics of the shrimp Artemesia longinaris in two regions in southeastern Brazil, one inside (Macaé—Rio de Janeiro State) and one outside (Ubatuba—State of São Paulo) the Cabo Frio upwelling area. The aim was to verify the influence of the upwelling phenomenon on the abundance, growth, longevity, size of sexual maturity, and reproductive period of the species. In total, 188,902 individuals were captured at Macaé and 3,461 at Ubatuba. Individuals captured at Macaé showed larger maximum size, higher longevity, and slower growth rate, besides reaching sexual maturity at larger sizes than at Ubatuba. Continuous reproduction was observed in both regions, with juvenile recruitment peaks in spring and summer. Local conditions observed at Macaé were influenced by the Cabo Frio upwelling zone, characterized by productive and cooler waters that are around 20°C during most of the year. The upwelling phenomenon is probably the main factor influencing the population parameters studied here, changing the geographic patterns previously observed for the variation of these parameters in A. longinaris.  相似文献   

Gentrification in Porto: floating city users and internationally-driven urban change     

Luís Carvalho  José Fernandes  Jorge Pinto 《Urban geography》2019,40(4):565-572

The heightening scale of urban tourism and the fast-growing number of “floating” city users raise new challenges to understand contemporary urban change – namely for internationally open, heritage-rich medium-sized cities. Discussing the case of Porto at a time when the contested notion of gentrification infuses local politics, we highlight the transnational drivers of this process in Portugal´s second city. While acknowledging perils and benefits, we argue that more than simply leaving a footprint to be solved with taxation, internationally-driven gentrification may endanger city diversity and identity, raising implications for urban policy and for our understanding of local development as a whole.  相似文献   

Assessing the effects of land cover and future climate conditions on the provision of hydrological services in a medium‐sized watershed of Portugal          下载免费PDF全文

Claudia Carvalho‐Santos  João Pedro Nunes  António T. Monteiro  Lars Hein  João Pradinho Honrado 《水文研究》2016,30(5):720-738

The separated and combined effects of land‐cover scenarios and future climate on the provision of hydrological services were evaluated in Vez watershed, northern Portugal. Soil and Water Assessment Tool was calibrated against daily discharge, sediments and nitrates, with good agreements between model predictions and field observations. Four hypothetical land‐cover scenarios were applied under current climate conditions (eucalyptus/pine, oak, agriculture/vine and low vegetation). A statistical downscaling of four General Circulation Models, bias‐corrected with ground observations, was carried out for 2021–2040 and 2041–2060, using representative concentration pathway 4.5 scenario. Also, the combined effects of future climate conditions were evaluated under eucalyptus/pine and agriculture/vine scenario. Results for land cover revealed that eucalyptus/pine scenario reduced by 7% the annual water quantity and up to 17% in the summer period. Although climate change has only a modest effect on the reduction of the total annual discharge (?7%), the effect on the water levels during summer was more pronounced, between ?15% and ?38%. This study shows that climate change can affect the provision of hydrological services by reducing dry season flows and by increasing flood risks during the wet months. Regarding the combined effects, future climate may reduce the low flows, which can be aggravated with eucalyptus/pine scenario. In turn, peak flows and soil erosion can be offset. Future climate may increase soil erosion and nitrate concentration, which can be aggravated with agriculture scenario. Results moreover emphasize the need to consider both climate and land‐cover impacts in adaptation and land management options at the watershed scale. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Distribution of metals in soils and plants around mineralized zones at Cartagena-La Unión mining district (SE,Spain)   总被引：1，自引：1，他引：0  

O. Gonzalez-Fernandez  I. Queralt  J. I. Manteca  G. Garcia  M. L. Carvalho 《Environmental Earth Sciences》2011,63(6):1227-1237

A geochemical and mineralogical characterization of three zones (namely oxides zones, hydrothermal alteration zone and mining wastes zone) from a mineralized zone in the upper part of the Cartagena-La Unión range was carried out by analysing rocks, soils and three plant species (Piptatherum miliaceum, Ditrichia viscosa and Hirsfeldia incana). The transference and bioavailability of some metals (especially Pb, Zn, As and Fe) from soils to plants was also checked. Results show that rocks have a large content of Fe and Pb which are transferred to surrounding soils also highly enriched in these elements (Fe ranges from 9 to 35% and Pb 1 to 2.9%). Regarding soil to plant transfer, it was shown a differential behaviour for both the three plant species and the soil zones, with a higher level of metal accumulation rates for Piptatherum miliaceum in the hydrothermal alteration zone. Values of accumulation rates obtained for Pb in Piptatherum miliaceum allow considering it a good choice for phytoremediation purposes.  相似文献   

Chemistry of the Ferraria thermal water, S. Miguel Island, Azores: mixing and precipitation processes   总被引：1，自引：1，他引：0  

Maria do Rosário Carvalho  António Mateus  Jo?o C. Nunes  José M. Carvalho 《Environmental Earth Sciences》2011,64(2):539-547

The Ferraria thermal water emerges at the sea level in the Ferraria lava delta (western edge of S. Miguel Island, Azores) with temperature of ca. 60°C and pH varying between 5.4 and 6.2. It is of sodium chloride type, resulting from ca. 50% seawater mixing with an acid brackish, at ≈100°C, denoting the presence of significant CO₂(g) and the progress of water–rock interactions in open system conditions. The thermal Na–Cl water is strongly enriched with Sr and Mn and, comparatively, has low concentrations in Al, Fe and As. These elements are removed from the solution as critical conditions for the formation of several neo-formed mineral phases are gradually attained. Thermodynamic equilibrium calculations are consistent with this interpretation, showing that the thermal fluid can precipitate Fe³⁺-(hydr-)oxides, kaolinite and non-crystalline silica. Wells logging show fracture planes and pores fully/partly filled up with polyphase botryoidal aggregates mostly composed of goethite + ferrihydrite and displaying variable adsorbed contents of Si, P and As. These neo-formed phases result from the pristine fluid oxidation due to seawater mixing; its precipitation is easily affected by pH and redox variations of the brackish, due to volcanic gases pressure alterations, and fluid pressure or flow-velocity oscillation in the fractured aquifer.  相似文献   

Geochemistry of granites and metasediments of the urban area of Vila Real (northern Portugal) and correlative radon risk   总被引：2，自引：2，他引：0  

M. E. P. Gomes  L. J. P. F. Neves  F. Coelho  A. Carvalho  M. Sousa  A. J. S. C. Pereira 《Environmental Earth Sciences》2011,64(2):497-502

Radon concentration was evaluated in dwellings of the urban area of Vila Real (Northern Portugal). The area is mainly composed of Hercynian granites and Cambrian metasediments, and CR-39 passive detectors (n = 112) were used for the purpose. The results obtained in winter conditions suggest that the most productive geological unit is the Hercynian granite G1 (geometric mean of 364 Bq/m³), while Cambrian metasediments of the Douro Group show the lowest average indoor radon concentration (236 Bq/m³). The geological, geochemical and radiological data obtained suggest that the most effective control on the radon concentrations of the area is related with the uranium content of the rocks; indeed, the highest contents were observed in granite G1 (21 ppm) and the lowest in the metasediments (3 ppm). This is also confirmed by the results obtained for groundwater, where granites present the highest concentrations of dissolved radon (up to 938 Bq/l), uranium (5–18 ppb) and gross α activities (0.47–0.92 Bq/l). No important radiometric anomalies were found in relation with geological structures such as faults, veins and contacts, but a moderate increase of the uranium content can occur locally in such structures. Petrographic observations and SEM studies show that uranium is mainly contained within the rock in heavy accessory minerals (apatite, zircon, monazite, xenotime), which reduces radon emanation. Notwithstanding, due to the high U contents granites show a significant potential to induce indoor radon concentrations in dwellings in excess of the recommended value of 400 Bq/m³. Overall, we can conclude that the region of Vila Real presents a moderate to high radon risk in dwellings and groundwater.  相似文献