Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (56)

Search Parameters:
Keywords = topographic characterisation

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
35 pages, 29215 KB  
Article
Unprotected Urban Sand Dunes Under Anthropogenic Pressure and Risk of Habitat Loss: Using UAS–LiDAR Data to Support Conservation Along the Bulgarian Black Sea Coast
by Bogdan Prodanov, Radoslava Bekova, Chavdar Gussev, Magdalena Valcheva, Todor Lambev, Ahinora Baltakova, Julian Popov, Dobroslav Dechev, Lyubomir Rasovski, Nadezhda Dimitrova and Liya Radoslavova
Conservation 2026, 6(2), 50; https://doi.org/10.3390/conservation6020050 - 21 Apr 2026
Viewed by 149
Abstract
Coastal beach–dune systems along the Western Black Sea Coast represent geomorphologically complex and ecologically valuable environments that have been increasingly affected by long-term urbanisation and recreational pressure. This study examines the geomorphological settings, sedimentary connectivity and associated Natura 2000 dune habitats within two [...] Read more.
Coastal beach–dune systems along the Western Black Sea Coast represent geomorphologically complex and ecologically valuable environments that have been increasingly affected by long-term urbanisation and recreational pressure. This study examines the geomorphological settings, sedimentary connectivity and associated Natura 2000 dune habitats within two urbanised beach–dune systems, Pobeda (Burgas) and Asparuhovo (Varna), to improve their cadastral documentation and support objective conservation assessment. The analysis is based on high-resolution UAS-LiDAR surveys, complemented by UAS photogrammetry and field observations, allowing detailed three-dimensional characterisation of dune landforms, surface morphology and habitat patterns. The results identify foredune-dominated system architectures in both study areas, with the Pobeda (Burgas) and Asparuhovo (Varna) beach–dune systems comprising embryonic dunes, established foredune ridges and low-relief foredune plains, variably developed and spatially fragmented as a result of long-term urbanisation and recreational pressure, and spatially associated with dune habitats. Despite substantial anthropogenic modification, these elements remain recognisable, although locally fragmented and morphologically degraded. Subtle topographic changes related to trampling, informal access routes and surface compaction were detected, particularly affecting foredune crests and foredune plains, with implications for sediment transport continuity and habitat stability. The study shows that conventional habitat inventories alone are insufficient for capturing such changes. Integrated geomorphological and habitat analysis based on UAS-LiDAR provides a reliable framework for accurate mapping, conservation status assessment and informed consideration of coastal dune systems within the Natura 2000 network and related protection schemes. Full article
Show Figures

Figure 1

31 pages, 21197 KB  
Article
Research on Road Slope Estimation and the Passable Area Modelling Method in Hilly and Mountainous Areas Based on Multi-Sensor Fusion
by Hequan Miao, Chunjiang Bao, Jian Wu and Peisong Diao
Agriculture 2026, 16(7), 776; https://doi.org/10.3390/agriculture16070776 - 31 Mar 2026
Viewed by 323
Abstract
Autonomous tractors have been shown to possess the capability to ensure a high degree of operational precision during seeding activities on flat terrain. However, in topographically challenging environments characterised by significant elevations and pronounced variations in slope, factors such as road gradients have [...] Read more.
Autonomous tractors have been shown to possess the capability to ensure a high degree of operational precision during seeding activities on flat terrain. However, in topographically challenging environments characterised by significant elevations and pronounced variations in slope, factors such as road gradients have been shown to compromise the precision of satellite-based positioning systems. This, in turn, can lead to alterations in vehicle posture and the generation of disparate longitudinal driving forces between the left and right tyres. It is important to note that this deviation from the predefined path has the potential to result in rollover accidents. Evidence has been presented that indicates a correlation between road gradient and vehicle roll motion. The proposed methodology is an algorithmic approach to the estimation of lateral slope, integrating inertial measurement unit (IMU) sensors and ground-based ultrasonic radars. This algorithmic approach is proposed as a means to achieve more accurate estimations of lateral slope. The initial development of the vehicle dynamics model was based on slope operation requirements, and the model was endowed with eight degrees of freedom. The utilisation of an unscented Kalman filter (UKF) facilitates the integration of inertial measurement unit (IMU) and ground-based ultrasonic radar measurements, thereby enabling real-time estimation of key motion states, such as lateral slope. The validity of the proposed algorithm was established through a combination of hardware-in-the-loop testing and field trials involving real tractors. The findings indicate that the implementation of this algorithm leads to a substantial enhancement in the trajectory tracking accuracy of tractors during slope operations. This enhancement is characterised by a substantial reduction in lateral deviation and an effective augmentation in the operational pass rate. In the course of empirical trials conducted in a mountainous environment, the lateral positioning deviation during straight-line driving was diminished from 10 cm to within 5 cm. Concurrently, the precision of lateral slope estimation was enhanced to 0.04 degrees. Full article
(This article belongs to the Special Issue Intelligent Agricultural Seeding Equipment)
Show Figures

Figure 1

18 pages, 2964 KB  
Article
Factors Supporting a High Level of Understorey Plant Diversity in Ravine Forests (EU Priority Habitat Type)
by Lado Kutnar, Anže Martin Pintar, Aleksander Marinšek and Janez Kermavnar
Forests 2026, 17(3), 370; https://doi.org/10.3390/f17030370 - 16 Mar 2026
Cited by 1 | Viewed by 411
Abstract
In addition to being influenced by global drivers, forest herb-layer communities are also shaped by various local factors, such as topography, stand characteristics and soil properties. The responses of ground vegetation were studied in the ravine forests of a Natura 2000 site in [...] Read more.
In addition to being influenced by global drivers, forest herb-layer communities are also shaped by various local factors, such as topography, stand characteristics and soil properties. The responses of ground vegetation were studied in the ravine forests of a Natura 2000 site in eastern Slovenia. A high species richness of 218 plant species was observed in the herb layer, including some woody species. On average, 52.8 different plant species were recorded per plot. Species richness was significantly associated with topographic and forest stand factors, rather than soil characteristics. It was positively associated with altitude and the amount of deadwood and negatively associated with tree height. However, the main predictors for the species composition of the ground vegetation were tree layer cover and soil pH. Among the studied ravine forests, Tilia-dominated stands are characterised by the highest species diversity and the lowest herb-layer cover, indicating a composition of less competitive, site-specific species inhabiting sites with high resource heterogeneity and diverse microhabitats. To preserve the high level of biodiversity of heterogeneous ravine forests and to maintain their favourable conservation status, it is crucial to sustain the natural state of forest soils and stands by implementing appropriate management measures. Such measures may include close-to-nature forest management, which is already being implemented in the studied ravine forests. Full article
(This article belongs to the Special Issue Species Diversity and Habitat Conservation in Forest)
Show Figures

Figure 1

7 pages, 1809 KB  
Communication
SiO2 Electret Formation via Stamp-Assisted Capacitive Coupling: A Chemophysical Surface Functionalisation
by Edoardo Chini, Denis Gentili, Andrea Liscio and Massimiliano Cavallini
Inorganics 2026, 14(1), 21; https://doi.org/10.3390/inorganics14010021 - 4 Jan 2026
Cited by 1 | Viewed by 530
Abstract
This work introduces a new method for creating patterned SiO2 electrets using stamp-assisted capacitive coupling (SACC), enabling surface functionalisation without direct electrode contact. SACC applies an alternating current through capacitive coupling between a conductive stamp and an insulating substrate in high-humidity conditions, [...] Read more.
This work introduces a new method for creating patterned SiO2 electrets using stamp-assisted capacitive coupling (SACC), enabling surface functionalisation without direct electrode contact. SACC applies an alternating current through capacitive coupling between a conductive stamp and an insulating substrate in high-humidity conditions, forming a nano-electrochemical cell that drives localised reactions. Using thermally grown SiO2 films, we achieve submicrometre patterning with minimal topographical impact but significant electronic alterations. Characterisation via Kelvin Probe Force Microscopy and Electric Force Microscopy confirms the formation of charged regions replicating the stamp pattern, with adjustable surface potential shifts up to −1.7 V and charge densities reaching 300 nC·cm−2. The process can be scaled to areas of 1 cm2 and is compatible with conventional laboratory equipment, offering a high-throughput alternative to scanning-probe lithography. SACC combines simplicity, accuracy, and scalability, opening new opportunities for patterned electret production and functional surface engineering. Full article
(This article belongs to the Special Issue Featured Papers in Inorganic Materials 2025)
Show Figures

Graphical abstract

23 pages, 8392 KB  
Article
Analysis of Critical “Source-Area-Period” of Agricultural Non-Point Source Pollution in Typical Hilly and Mountainous Areas: A Case Study of Yongchuan District, Chongqing City, China
by Yanrong Lu, Xiuhong Li, Meiying Sun, Le Zhang, Yuying Zhang, Yitong Yin and Rongjin Yang
Agriculture 2026, 16(1), 103; https://doi.org/10.3390/agriculture16010103 - 31 Dec 2025
Viewed by 488
Abstract
Significant achievements have been made in the control of point source pollution. However, agricultural non-point source pollution (AGNPSP) has become a serious threat to ecological environment quality and is now the main source of pollution in the Yangtze River Basin. The topographical features [...] Read more.
Significant achievements have been made in the control of point source pollution. However, agricultural non-point source pollution (AGNPSP) has become a serious threat to ecological environment quality and is now the main source of pollution in the Yangtze River Basin. The topographical features of the upper Yangtze River region are primarily characterised by hilly and mountainous terrain, marked by steep slopes and pronounced undulations. This renders the land susceptible to soil erosion, thereby becoming a significant conduit for the entry of AGNPSP into water bodies. Consequently, there is an urgent need to identify critical sources, areas and periods of AGNPSP and to promote the effective prevention and control of such pollution. The present study adopted the Yongchuan District of Chongqing, a region characterised by hilly and mountainous terrain in the upper reaches of the Yangtze River, as a case study. The research, conducted from 2018 to 2021, sought to identify the “critical sources—areas—periods“ of AGNPSP. In order to surmount the challenge posed by the absence of fundamental data, the study constructed and integrated three models. The export coefficient model was used to calculate the pollution load, the pollutant load intensity model was used for spatial analysis, and the equal-scale pollution load equation was used to assess the contribution degree of different pollutants. Furthermore, the study developed a monthly pollutant flux model to accurately identify the critical pollution periods within the year. In conclusion, the research results have indicated the necessity of a governance strategy that is to be implemented with utmost priority. This strategy is to be based on the following hierarchy: critical sources, areas, and periods. The results of the study indicate the following: (1) The pollutants that exhibit the greatest contribution in Yongchuan District are total nitrogen (TN)and chemical oxygen demand (COD), accounting for 34% and 33%, respectively. The primary source of pollution is attributed to livestock and poultry breeding, accounting for 49.7% of the total pollution load. (2) The critical area of AGNPSP in Yongchuan District is located in the south of the district and primarily comprises Zhutuo Town, Hegeng Town and Xianlong Town. Among the critical areas identified, livestock and poultry farming accounts for 68% of the pollution load. (3) The monthly variation of pollutant fluxes demonstrates a single peak pattern, with the peak occurring in June. The data indicates that the flux of pollutants in June and July accounted for 37% of the total, thus identifying these months as critical periods for the management of AGNPSP in Yongchuan District. The critical source–area–period analysis indicates that the comprehensive management strategy for AGNPSP should focus on critical sources, areas and periods. Furthermore, it should adopt a prioritised, zoned and phased management approach. This approach has the potential to promote cost-effective and efficient prevention and control, thereby facilitating the achievement of sustainable agricultural development. Full article
(This article belongs to the Section Agricultural Soils)
Show Figures

Figure 1

17 pages, 12851 KB  
Article
The Fenestras Elisabeth Complex (Nova Structura) in the Parietal Bone of Plecotus auritus: Morphology, Topography, and Functional Significance
by Grzegorz Kłys and Paweł Socha
Animals 2026, 16(1), 109; https://doi.org/10.3390/ani16010109 - 30 Dec 2025
Viewed by 625
Abstract
Fenestrations of mammalian skull bones are rare and poorly understood, particularly within the parietal bone. In bats—a group characterised by advanced sensory specialisation and echolocation—superficial modifications of the cranial vault may have functional significance, yet their occurrence and organisation remain insufficiently documented. In [...] Read more.
Fenestrations of mammalian skull bones are rare and poorly understood, particularly within the parietal bone. In bats—a group characterised by advanced sensory specialisation and echolocation—superficial modifications of the cranial vault may have functional significance, yet their occurrence and organisation remain insufficiently documented. In this study, we describe an exceptional fenestrated complex in the posterolateral parietal bone of Plecotus auritus, comprising structural elements not previously recorded within Vespertilionidae. The aim of the study was to characterise in detail the morphology, topography, and variability of the surface structure termed Fenestras Elisabeth (nova structura), with particular emphasis on its relationship with the auditory region and its potential biomechanical–acoustic significance. The material consisted of ten skulls of P. auritus, examined using micro-CT scanning, 3D reconstruction, and qualitative analysis of fenestrated structures and their topographic relationships. Within the posterolateral parietal region, we identified an extensive and repeatable fenestrated complex comprising numerous fenestrae parietales Elisabeth, paired fenestrula Elisabeth, a central depression (recessus acousticus parietalis), and a bordering fissure (fissura occipitalis mastoidea, nova structura topographica). The complex exhibited a stable spatial organisation despite individual variation in the number and shape of the openings. All fenestrations were confined to the posterolateral zone, and the contact between the fenestrae and the fissura occipitalis mastoidea represented a diagnostic feature. Our analysis suggests that the Fenestras Elisabeth complex may be associated with combined biomechanical and acoustic constraints: (1) a biomechanical role—reducing strain in the parietal lamina during movements of the extremely mobile and elongated pinnae; and (2) an acoustic role—modulating micro-vibrations transmitted to the inner-ear structures. Individual variability and lateral asymmetry of fenestration patterns indicate a high degree of adaptive plasticity in this region of the skull. This study provides the first documentation of a large, structurally organised parietal-bone fenestration complex in Plecotus auritus, expanding current knowledge of bat cranial morphology and suggesting a likely functional significance for these previously unknown bony structures. Full article
(This article belongs to the Section Mammals)
Show Figures

Figure 1

10 pages, 4421 KB  
Article
Effect of Layer Exposure Time in SLA-LCD Printing on Surface Topography, Hardness and Chemical Structure of UV-Cured Photopolymer
by Bartosz Pszczółkowski and Magdalena Zaborowska
Lubricants 2025, 13(9), 406; https://doi.org/10.3390/lubricants13090406 - 11 Sep 2025
Cited by 5 | Viewed by 1512
Abstract
The exposure parameters in stereolithography with liquid crystal display (SLA-LCD) influence the functional properties of photopolymers, which is particularly important for tribological applications. In this study, the influence of the exposure time of the layers (2–8 s) on the surface topography (ISO 25178), [...] Read more.
The exposure parameters in stereolithography with liquid crystal display (SLA-LCD) influence the functional properties of photopolymers, which is particularly important for tribological applications. In this study, the influence of the exposure time of the layers (2–8 s) on the surface topography (ISO 25178), Brinell hardness (HB) and chemical structure (FTIR spectroscopy) of UV-cured resin samples is investigated. Both insufficient and excessive UV irradiation led to undesirable effects ranging from incomplete cross-linking and surface irregularities to excessive curing, micro-cracking and increased surface kurtosis (high Sku values). The most balanced mechanical and topographical performance was observed at a layer exposure time of 6 s, characterised by low Spk values, uniform surface texture and high cohesion between layers. FTIR analysis confirmed the progressive cross-linking with increasing exposure time. The results show that precise control of irradiation parameters enables optimisation of the interrelationships between microstructure, mechanical properties and surface functionality, which is critical for improving the durability and performance of components operating under boundary or mixed lubrication. Full article
Show Figures

Figure 1

9 pages, 1772 KB  
Article
Cliff-Front Dune Development During the Late Pleistocene at Sa Fortalesa (Mallorca, Western Mediterranean)
by Laura del Valle, Federica Perazzotti and Joan J. Fornós
Geosciences 2025, 15(7), 260; https://doi.org/10.3390/geosciences15070260 - 5 Jul 2025
Cited by 1 | Viewed by 895
Abstract
This study presents the first detailed analysis of a Late Pleistocene cliff-front dune in northern Mallorca (Western Mediterranean). The research is based on sedimentological fieldwork conducted in a disused coastal quarry, where stratigraphic columns were recorded and facies were described in detail. Grain [...] Read more.
This study presents the first detailed analysis of a Late Pleistocene cliff-front dune in northern Mallorca (Western Mediterranean). The research is based on sedimentological fieldwork conducted in a disused coastal quarry, where stratigraphic columns were recorded and facies were described in detail. Grain size analysis was performed using image-based measurements from representative samples, and palaeowind conditions were reconstructed through the analysis of cross-bedding orientations and empirical wind transport equations. The dune, corresponding to Unit U4, exhibits three distinct evolutionary stages: initial, intermediate, and final. During the initial stage, sediment mobilisation required wind speeds of approximately 10 m/s from the south-southwest (SSW). The intermediate stage was characterised by variable wind velocities between 5 and 8 m/s from the west-southwest (WSW). In the final stage, average wind speeds reached 7 m/s from the west (W), with intermittent peaks up to 10 m/s. These findings underscore the critical influence of wind regime and topographic constraints on aeolian sedimentation processes. By reconstructing wind dynamics and analysing sedimentary architecture, this work provides key insights into the interplay between climatic drivers and geological context in the development of coastal aeolian systems. Full article
(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)
Show Figures

Figure 1

24 pages, 5633 KB  
Article
Architectural Analysis for Novel Olive Crop Management
by Khouloud Annabi, Faouzi Haouala, AbdelKarim Hamrita, Rania Kouki, Foued Laabidi, Mokhtar Rejili, Samra Akef Bziouech and Mouna Mezghani Aïachi
Plants 2025, 14(11), 1707; https://doi.org/10.3390/plants14111707 - 3 Jun 2025
Cited by 1 | Viewed by 1128
Abstract
Efficient fruit production, quality improvement, and timely harvesting are essential in olive cultivation, which requires optimised distribution and management of fruiting sites. This study aimed to support sustainable olive crop management by analysing the morphological characteristics of five cultivars (Chemlali, Chetoui [...] Read more.
Efficient fruit production, quality improvement, and timely harvesting are essential in olive cultivation, which requires optimised distribution and management of fruiting sites. This study aimed to support sustainable olive crop management by analysing the morphological characteristics of five cultivars (Chemlali, Chetoui, Koroneiki, Meski, and Picholine) under semi-arid Tunisian conditions. Through a detailed architectural analysis, we investigated the relationships between branching patterns, density, distribution of inflorescence and fruit sites, biometric traits (shoot length, internode number, and shoot dimensions), and geometric variability within each cultivar. Three trees per cultivar were analysed across three architectural units. The results showed marked architectural differences, highlighting the need for cultivar-specific strategies in planting, pruning, and orchard management. The distribution of shoots across botanical orders revealed unique branching patterns: Chemlali and Koroneiki showed thinner shoots and higher shoot density, reflecting strong apical dominance and their suitability for hyper-intensive systems. In addition, nonsignificant differences in long shoots’ insertion angles between Meski, Chetoui, and Koroneiki suggest compatibility for co-cultivation, facilitating mechanised maintenance and harvesting. Emphasis on inter-cultivar compatibility and architectural coherence is crucial for orchard design. These findings provide important insights for optimising orchard management practices to improve productivity, fruit quality, and operational efficiency. Full article
(This article belongs to the Special Issue Development of Woody Plants)
Show Figures

Graphical abstract

16 pages, 4187 KB  
Article
A Proposal for Rapid Assessment of Long-Distance Oil and Gas Pipelines After Earthquakes
by Hongyuan Jing, Liang Huang, Hua Liu, Weijun Jiang, Qinglu Deng and Ruiqing Niu
Appl. Sci. 2025, 15(7), 3595; https://doi.org/10.3390/app15073595 - 25 Mar 2025
Cited by 3 | Viewed by 1770
Abstract
A substantial proportion of long-distance oil and gas pipelines in China traverse active faults and high-risk areas characterised by intricate topographic and geological environments. These pipelines are susceptible to a range of safety concerns, exacerbated by the increasing frequency of strong earthquakes in [...] Read more.
A substantial proportion of long-distance oil and gas pipelines in China traverse active faults and high-risk areas characterised by intricate topographic and geological environments. These pipelines are susceptible to a range of safety concerns, exacerbated by the increasing frequency of strong earthquakes in recent years. To address this issue, a comprehensive risk investigation framework has been proposed for long-distance oil and gas pipelines following seismic events. This initiative aims to ensure the safety of pipeline transportation. In this paper, the elements of pipeline safety evaluation under the influence of coseismic hazards are first organized, followed by a construction of post-earthquake pipeline safety rapid assessment theoretical framework based on the seismic geological disaster risk evaluation system. Each method in the system is then introduced one by one. Unlike existing studies that predominantly focus on localized fault activity or static risk assessment, our framework introduces three key innovations: (1) a hierarchical integration of multi-source monitoring data (SCADA, UAV-AI, and numerous monitoring devices) into a unified GIS platform, overcoming the fragmentation of existing systems; (2) a dynamic four-step evaluation process (susceptibility → hazard → risk → safety) that incorporates both pre-earthquake geological conditions and post-earthquake real-time triggers (e.g., PGA, rainfall); (3) a novel risk matrix mechanism for pipeline safety, which dynamically updates risk levels based on field monitoring data rather than relying solely on probabilistic models. This study provides a novel theoretical framework for assessing the safety of pipelines after earthquakes, which can provide a timely basis for pipeline management decisions and reduce the potential damage to pipelines caused by earthquakes. It is important to note that this framework is still in a preliminary stage and needs to be continuously deepened and optimised. Full article
(This article belongs to the Section Earth Sciences)
Show Figures

Figure 1

21 pages, 1865 KB  
Review
Sustainable Active Travel in Environmentally Challenging Cities: A Systematic Review of Barriers and Strategies
by Muhammad Tsaqif Wismadi, Yngve Karl Frøyen and Adil Rasheed
Sustainability 2025, 17(3), 1276; https://doi.org/10.3390/su17031276 - 5 Feb 2025
Cited by 2 | Viewed by 3896
Abstract
Active travel modes, such as walking and cycling, are essential for fostering sustainable urban transportation. However, their adoption in environmentally challenging areas—characterised by steep slopes, extreme weather, and rugged terrain—presents significant obstacles. This study addresses these challenges by conducting a systematic literature review [...] Read more.
Active travel modes, such as walking and cycling, are essential for fostering sustainable urban transportation. However, their adoption in environmentally challenging areas—characterised by steep slopes, extreme weather, and rugged terrain—presents significant obstacles. This study addresses these challenges by conducting a systematic literature review of studies published between 2000 and 2024 to identify strategies that promote active travel in such contexts. Using a structured five-step methodology, 62 relevant articles were selected and analysed to explore common challenges and propose tailored solutions. The findings highlight critical barriers, including topographical difficulties, harsh climatic conditions, and adverse weather, all of which hinder walking and cycling. To address these barriers, this study identifies a range of solutions, including infrastructure enhancements such as bike lifts, e-bike systems, shaded walkways, and heated pavements, as well as policy measures like financial incentives and disincentive regulations. Importantly, this study makes a deliberate effort to avoid overgeneralised solutions by emphasising the need for interventions that are context-sensitive and tailored to specific environmental challenges, urban scales, and local conditions. By providing options for actionable strategies, this research offers a comprehensive foundation for developing inclusive and sustainable policies that encourage active travel in diverse and environmentally constrained urban settings. Full article
(This article belongs to the Section Sustainable Transportation)
Show Figures

Figure 1

21 pages, 5093 KB  
Article
Bio-Optical Response of Phytoplankton and Coloured Detrital Matter (CDM) to Coastal Upwelling in the Northwest South China Sea
by Guifen Wang, Wenlong Xu, Shubha Sathyendranath, Wen Zhou and Wenxi Cao
Remote Sens. 2025, 17(1), 44; https://doi.org/10.3390/rs17010044 - 26 Dec 2024
Viewed by 1244
Abstract
To examine the bio-optical response to coastal upwelling, we measured inherent optical properties (IOPs) and biogeochemical parameters simultaneously off Hainan Island in the northwest part of the South China Sea (SCS) during late summer 2013. Bio-optical relationships between IOPs and phytoplankton were used [...] Read more.
To examine the bio-optical response to coastal upwelling, we measured inherent optical properties (IOPs) and biogeochemical parameters simultaneously off Hainan Island in the northwest part of the South China Sea (SCS) during late summer 2013. Bio-optical relationships between IOPs and phytoplankton were used for calculating vertical profiles of the total chlorophyll a concentration (Chl-a) and the absorption by coloured detrital matter (CDM). These bio-optical properties, which showed distinct horizontal and vertical distributions across the continental shelf, were strongly influenced by upwelling processes, as well as the shelf topography. Phytoplankton biomass and CDM absorption in surface waters showed much higher values along the coast, with their spatial distributions related to topographic variability. Vertical distributions of phytoplankton were characterised by a subsurface chlorophyll maximum (SCM) layer. The strongest SCM (Chl-a = 4.22 mg m−3) was observed at 24 m depth in coastal waters near the northeast cape of Hainan Island. The depth of the SCM varied between 16 and 60 m at different stations, appearing to coincide with the isotherm of 22 °C. The SCM depth was inversely correlated with the magnitude of the SCM. Different shapes of Chl-a profiles were observed, which suggested that the vertical distributions of phytoplankton biomass were driven by different environmental factors. Elevated concentrations of CDM were mainly observed near the bottom, which suggest that the benthic nepheloid layer may be an important source of detrital material. The relationship between the absorption coefficient of CDM at 443 nm, aCDM(443), and Chl-a exhibited distinct differences between waters in upper ocean and in bottom layers, with the threshold depth being modulated by shelf topography. Our results highlight the utility of bio-optical observations with high resolution for better understanding the coupling between physical forcing and biogeochemical variability. Full article
Show Figures

Figure 1

21 pages, 51554 KB  
Article
Airborne LiDAR Applications at the Medieval Site of Castel Fenuculus in the Lower Valley of the Calore River (Benevento, Southern Italy)
by Antonio Corbo
Land 2024, 13(12), 2255; https://doi.org/10.3390/land13122255 - 23 Dec 2024
Cited by 1 | Viewed by 2154
Abstract
This paper explores the application of Airborne Laser Scanning (ALS) technology in the investigation of the medieval Norman site of Castel Fenuculus, in the lower Calore Valley, Southern Italy. This research aims to assess the actual potential of the ALS dataset provided by [...] Read more.
This paper explores the application of Airborne Laser Scanning (ALS) technology in the investigation of the medieval Norman site of Castel Fenuculus, in the lower Calore Valley, Southern Italy. This research aims to assess the actual potential of the ALS dataset provided by the Italian Ministry of the Environment (MATTM) for the detection and visibility of archaeological features in a difficult environment characterised by dense vegetation and morphologically complex terrain. The study focuses on improving the detection and interpretation of archaeological features through a systematic approach that includes the acquisition of ALS point clouds, the implementation of classification algorithms, and the removal of vegetation layers to reveal the underlying terrain and ruined structures. Furthermore, the aim was to test different classification and filtering techniques to identify the best one to use in complex contexts, with the intention of providing a comprehensive and replicable methodological framework. Finally, the Digital Elevation Model (DTM), and various LiDAR-derived models (LDMs), were generated to visualise and highlight topographical features potentially related to archaeological remains. The results obtained demonstrate the significant potential of LiDAR in identifying and documenting archaeological features in densely vegetated and wooded landscapes. Full article
(This article belongs to the Section Landscape Archaeology)
Show Figures

Figure 1

21 pages, 7204 KB  
Technical Note
A Method for Developing a Digital Terrain Model of the Coastal Zone Based on Topobathymetric Data from Remote Sensors
by Mariusz Specht and Marta Wiśniewska
Remote Sens. 2024, 16(24), 4626; https://doi.org/10.3390/rs16244626 - 10 Dec 2024
Cited by 2 | Viewed by 2463
Abstract
This technical note aims to present a method for developing a Digital Terrain Model (DTM) of the coastal zone based on topobathymetric data from remote sensors. This research was conducted in the waterbody adjacent to the Vistula Śmiała River mouth in Gdańsk, which [...] Read more.
This technical note aims to present a method for developing a Digital Terrain Model (DTM) of the coastal zone based on topobathymetric data from remote sensors. This research was conducted in the waterbody adjacent to the Vistula Śmiała River mouth in Gdańsk, which is characterised by dynamic changes in its seabed topography. Bathymetric and topographic measurements were conducted using an Unmanned Aerial Vehicle (UAV) and two hydrographic methods (a Single-Beam Echo Sounder (SBES) and a manual survey using a Global Navigation Satellite System (GNSS) Real-Time Kinematic (RTK) receiver). The result of this research was the development of a topobathymetric chart based on data recorded by the above-mentioned sensors. It should be emphasised that bathymetric data for the shallow waterbody (less than 1 m deep) were obtained based on high-resolution photos taken by a UAV. They were processed using the “Depth Prediction” plug-in based on the Support Vector Regression (SVR) algorithm, which was implemented in the QGIS software as part of the INNOBAT project. This plug-in allowed us to generate a dense cloud of depth points for a shallow waterbody. Research has shown that the developed DTM of the coastal zone based on topobathymetric data from remote sensors is characterised by high accuracy of 0.248 m (p = 0.95) and high coverage of the seabed with measurements. Based on the research conducted, it should be concluded that the proposed method for developing a DTM of the coastal zone based on topobathymetric data from remote sensors allows the accuracy requirements provided in the International Hydrographic Organization (IHO) Special Order (depth error ≤ 0.25 m (p = 0.95)) to be met in shallow waterbodies. Full article
(This article belongs to the Special Issue Remote Sensing: 15th Anniversary)
Show Figures

Figure 1

25 pages, 5924 KB  
Article
Capitalising on the Floristic Survey as a Non-Destructive Line of Evidence for Mineral Potential Modelling: A Case Study of Bauxite in South-Western Australia
by Lewis Trotter, Grant Wardell-Johnson, Andrew Grigg, Sarah Luxton and Todd P. Robinson
Land 2024, 13(12), 1995; https://doi.org/10.3390/land13121995 - 22 Nov 2024
Viewed by 1407
Abstract
While geobotanists have long used plant occurrence to locate subsurface resources, none have utilised floristic surveys as evidence in models of mineral potential. Here, we combine plant species distributions with terrain metrics to produce predictive models showing the probability of bauxite presence. We [...] Read more.
While geobotanists have long used plant occurrence to locate subsurface resources, none have utilised floristic surveys as evidence in models of mineral potential. Here, we combine plant species distributions with terrain metrics to produce predictive models showing the probability of bauxite presence. We identified nineteen taxa with statistically significant associations with known bauxite deposits and identified eleven terrain metrics from previous studies. We grouped variables into three variable sets (floristic, topographic, and topo-flora) and produced mineral potential models for each using four algorithms or approaches: (a) a generalised linear model (GLM); (b) random forest (RF); (c) maxent (ME); and (d) a heterogenous stacking ensemble (GLM-RF-ME). Overall, the random forest model outperformed all algorithms including the ensemble based on the area under the curve (AUC) metric. The floristic set of variables outperformed the topographic set (AUC: 0.86 v 0.82). However, together they had the greatest predictive capacity (AUC: 0.89). Six taxa, including Banksia grandis, Leucopogon verticillatus, and Persoonia longifolia, were indicators of bauxite presence, while five other taxa, including Xanthorrhoea preissii and Hypocalymma angustifolium, were associated with bauxite absence. Important topographic variables were topographic wetness, landscape position, and valley depth, which characterised bauxite locations as being well drained, in the upper slope positions of subdued hills, and at some distance from valleys. The addition of floristic surveys provides a new line of evidence about the overlying botanical life that tolerates, accumulates, or avoids bauxite or associated minerals. As opposed to drilling, both datasets can be collected and interrogated at low cost and without impact to the surrounding environment. These data are valuable additions to future applications of mineral potential modelling. Full article
(This article belongs to the Special Issue Geospatial Data in Landscape Ecology and Biodiversity Conservation)
Show Figures

Figure 1

Back to TopTop