Remote Sensing

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31 pages, 11888 KiB

Open AccessArticle

Evaluation and Modelling of the Coastal Geomorphological Changes of Deception Island since the 1970 Eruption and Its Involvement in Research Activity

by Cristina Torrecillas, Carmen Zarzuelo, Jorge de la Fuente, Bismarck Jigena-Antelo and Gonçalo Prates

Remote Sens. 2024, 16(3), 512; https://doi.org/10.3390/rs16030512 - 29 Jan 2024

Viewed by 580

Abstract

Deception Island is an active volcano with a submerged caldera open to the sea called Port Foster. Several post-caldera-collapsed volcanic events, as well as hydrodynamics, have changed its inner coastline, shaping new volcanic deposits. A hydrodynamic model is presented to predict accretion and [...] Read more.

Deception Island is an active volcano with a submerged caldera open to the sea called Port Foster. Several post-caldera-collapsed volcanic events, as well as hydrodynamics, have changed its inner coastline, shaping new volcanic deposits. A hydrodynamic model is presented to predict accretion and erosion trends in this bay, which could have an impact on the mobility of researchers and tourists. New historical orthophotos and spatio-temporal differences between digital elevation and bathymetric models were used for validation purposes. The model reveals that the south-facing coast is more susceptible to erosion, while the east- or west-facing coast experiences sedimentation. A visual study for the periods 1970–2003 and 2003–2020 in Port Foster obtained similar annual erosion/accretion lineal rates (0.3–2 m/year) in the areas not affected by the last eruptive period, as well as increases of 0.023 km²/year and 0.028 km²/year of the inner bay and coastal sedimentation rates of 0.007 km²/year and 0.002 km²/year, respectively. Only part of the significant total volume loss is received within the bay, including its own erosion, and accumulates on the bay bottom. This is largely because the volume input is composed of snow, and it is also due to the transfer of material outside to balance the figures. Full article

(This article belongs to the Special Issue Antarctic Remote Sensing Applications)

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26 pages, 29208 KiB

Open AccessEditor’s ChoiceArticle

A Green Fingerprint of Antarctica: Drones, Hyperspectral Imaging, and Machine Learning for Moss and Lichen Classification

by Juan Sandino, Barbara Bollard, Ashray Doshi, Krystal Randall, Johan Barthelemy, Sharon A. Robinson and Felipe Gonzalez

Remote Sens. 2023, 15(24), 5658; https://doi.org/10.3390/rs15245658 - 07 Dec 2023

Cited by 1 | Viewed by 3173

Abstract

Mapping Antarctic Specially Protected Areas (ASPAs) remains a critical yet challenging task, especially in extreme environments like Antarctica. Traditional methods are often cumbersome, expensive, and risky, with limited satellite data further hindering accuracy. This study addresses these challenges by developing a workflow that [...] Read more.

Mapping Antarctic Specially Protected Areas (ASPAs) remains a critical yet challenging task, especially in extreme environments like Antarctica. Traditional methods are often cumbersome, expensive, and risky, with limited satellite data further hindering accuracy. This study addresses these challenges by developing a workflow that enables precise mapping and monitoring of vegetation in ASPAs. The processing pipeline of this workflow integrates small unmanned aerial vehicles (UAVs)—or drones—to collect hyperspectral and multispectral imagery (HSI and MSI), global navigation satellite system (GNSS) enhanced with real-time kinematics (RTK) to collect ground control points (GCPs), and supervised machine learning classifiers. This workflow was validated in the field by acquiring ground and aerial data at ASPA 135, Windmill Islands, East Antarctica. The data preparation phase involves a data fusion technique to integrate HSI and MSI data, achieving the collection of georeferenced HSI scans with a resolution of up to 0.3 cm/pixel. From these high-resolution HSI scans, a series of novel spectral indices were proposed to enhance the classification accuracy of the model. Model training was achieved using extreme gradient boosting (XGBoost), with four different combinations tested to identify the best fit for the data. The research results indicate the successful detection and mapping of moss and lichens, with an average accuracy of 95%. Optimised XGBoost models, particularly Model 3 and Model 4, demonstrate the applicability of the custom spectral indices to achieve high accuracy with reduced computing power requirements. The integration of these technologies results in significantly more accurate mapping compared to conventional methods. This workflow serves as a foundational step towards more extensive remote sensing applications in Antarctic and ASPA vegetation mapping, as well as in monitoring the impact of climate change on the Antarctic ecosystem. Full article

(This article belongs to the Special Issue Antarctic Remote Sensing Applications)

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23 pages, 35455 KiB

Open AccessArticle

The Distribution of Surface Soil Moisture over Space and Time in Eastern Taylor Valley, Antarctica

by Mark R. Salvatore, John E. Barrett, Laura E. Fackrell, Eric R. Sokol, Joseph S. Levy, Lily C. Kuentz, Michael N. Gooseff, Byron J. Adams, Sarah N. Power, J. Paul Knightly, Haley M. Matul, Brian Szutu and Peter T. Doran

Remote Sens. 2023, 15(12), 3170; https://doi.org/10.3390/rs15123170 - 18 Jun 2023

Cited by 2 | Viewed by 1748

Abstract

Available soil moisture is thought to be the limiting factor for most ecosystem processes in the cold polar desert of the McMurdo Dry Valleys (MDVs) of Antarctica. Previous studies have shown that microfauna throughout the MDVs are capable of biological activity when sufficient [...] Read more.

Available soil moisture is thought to be the limiting factor for most ecosystem processes in the cold polar desert of the McMurdo Dry Valleys (MDVs) of Antarctica. Previous studies have shown that microfauna throughout the MDVs are capable of biological activity when sufficient soil moisture is available (~2–10% gravimetric water content), but few studies have attempted to quantify the distribution, abundance, and frequency of soil moisture on scales beyond that of traditional field work or local field investigations. In this study, we present our work to quantify the soil moisture content of soils throughout the Fryxell basin using multispectral satellite remote sensing techniques. Our efforts demonstrate that ecologically relevant abundances of liquid water are common across the landscape throughout the austral summer. On average, the Fryxell basin of Taylor Valley is modeled as containing 1.5 ± 0.5% gravimetric water content (GWC) across its non-fluvial landscape with ~23% of the landscape experiencing an average GWC > 2% throughout the study period, which is the observed limit of soil nematode activity. These results indicate that liquid water in the soils of the MDVs may be more abundant than previously thought, and that the distribution and availability of liquid water is dependent on both soil properties and the distribution of water sources. These results can also help to identify ecological hotspots in the harsh polar Antarctic environment and serve as a baseline for detecting future changes in the soil hydrological regime. Full article

(This article belongs to the Special Issue Antarctic Remote Sensing Applications)

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22 pages, 14069 KiB

Open AccessArticle

Ice Velocity Variations of the Cook Ice Shelf, East Antarctica, from 2017 to 2022 from Sentinel-1 SAR Time-Series Offset Tracking

by Siung Lee, Seohyeon Kim, Hyunjun An and Hyangsun Han

Remote Sens. 2023, 15(12), 3079; https://doi.org/10.3390/rs15123079 - 12 Jun 2023

Cited by 2 | Viewed by 1605

Abstract

The Cook Glacier drains a significant portion of the Wilkes Subglacial Basin, the largest subglacial basin in East Antarctica—which feeds the Cook Ice Shelf. The ice velocity of the Cook Ice Shelf needs to be monitored precisely and accurately, as it plays a [...] Read more.

The Cook Glacier drains a significant portion of the Wilkes Subglacial Basin, the largest subglacial basin in East Antarctica—which feeds the Cook Ice Shelf. The ice velocity of the Cook Ice Shelf needs to be monitored precisely and accurately, as it plays a critical role in determining the ice discharge from the Wilkes Subglacial Basin. In this study, we measured the annual ice velocities of the Cook Ice Shelf using the offset tracking technique on Sentinel-1 synthetic aperture radar images obtained from 2017 to 2022. Time-series offsets in the range and azimuth directions were determined from the offset tracking pairs with a temporal baseline of 36 days obtained from January to December of each year. Statistical evaluations of the spatiotemporal variations of the time-series offsets effectively eliminated the erroneous offsets in the original offset fields; the remaining offsets were then used to produce two-dimensional annual ice velocities. The direction of the ice flow of the Cook Ice Shelf was almost constant during the period 2017–2022, and the variations in the magnitude of annual ice velocities were investigated. The annual ice velocities of the Cook East Ice Shelf (CEIS) stayed constant and showed a gradual increase from the grounding line to the ice front, except in the western part. Ice velocities of the western part of the CEIS have not changed much at the grounding line during the 6-year period, while in the dynamic shelf ice zone, ice velocities accelerated by up to 22% because of the development of numerous crevasses and fractures. The ice velocities of the Cook West Ice Shelf (CWIS) were about two times higher than those of the CEIS and tended to increase rapidly from the grounding line to the ice front. The annual ice velocities at the grounding line of CWIS increased rapidly from 1330 to 1450 m/a over 6 years, with 70% of this acceleration observed after 2021. This was attributed to a reduction in the ice shelf volume because of the evolution of surface crevasses and rifts, leading to a decrease in the ice shelf’s buttressing potential. In particular, the loss of a portion of the dynamic shelf ice zone due to a series of ice front collapses in February 2022 likely caused the rapid speed-up of the ice shelf. The results of this study indicate that the buttressing potential of the CWIS and the western part of the CEIS has been significantly reduced, which could mean serious instability of the marine ice sheet in this region. Full article

(This article belongs to the Special Issue Antarctic Remote Sensing Applications)

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20 pages, 24486 KiB

Open AccessArticle

Deception Island 1967–1970 Volcano Eruptions from Historical Aerial Frames and Satellite Imagery (Antarctic Peninsula)

by Gonçalo Prates, Cristina Torrecillas, Manuel Berrocoso, Gabriel Goyanes and Gonçalo Vieira

Remote Sens. 2023, 15(8), 2052; https://doi.org/10.3390/rs15082052 - 13 Apr 2023

Cited by 2 | Viewed by 1586

Abstract

Aerial frames and satellite imagery are widely recognized data sources from which to produce maps. For volcanoes, maps enable the quantification of erupted ash and the destruction caused. The last eruptive sequence on Deception Island was endured from 1967 to 1970. Analogue maps [...] Read more.

Aerial frames and satellite imagery are widely recognized data sources from which to produce maps. For volcanoes, maps enable the quantification of erupted ash and the destruction caused. The last eruptive sequence on Deception Island was endured from 1967 to 1970. Analogue maps were produced via classical photogrammetric methods with a high degree of human intervention mainly to analyse the volcanic-centres areas only. However, historical aerial frames cover the whole of Deception Island. Structure from motion photogrammetry, a near-automated compilation of digital image processing strategies, minimizes the degree of human intervention to produce orthographic mosaics and digital elevation models from digital aerial frames. Orthographic mosaics were produced from historical aerial frames of 1956 and 1968, and a Kompsat-3 image of 2020. Their shared root-mean-square deviation was 1.8 m and 1.7 m in easting and northing, respectively, at ground control points measured with phase-differential global navigation satellite systems. The digital elevation models were processed with a root-mean-square deviation of 2.3 m and 3.6 m from 1956 and 1968 aerial frames, respectively. As the first application, erupted ashfall and the subsequent destruction, mainly at the former Chilean and British bases, were identified, and the volume of erupted ash was assessed to be over 0.16 km³ within the area mapped by these new digital cartographic products. Full article

(This article belongs to the Special Issue Antarctic Remote Sensing Applications)

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20 pages, 12149 KiB

Open AccessArticle

Sea Tide Influence on Ice Flow of David Drygalski’s Ice Tongue Inferred from Geodetic GNSS Observations and SAR Offset Tracking Analysis

by Luca Vittuari, Antonio Zanutta, Andrea Lugli, Leonardo Martelli and Marco Dubbini

Remote Sens. 2023, 15(8), 2037; https://doi.org/10.3390/rs15082037 - 12 Apr 2023

Viewed by 1243

Abstract

David Glacier and Drygalski Ice Tongue are massive glaciers in Victoria Land, Antarctica. The ice from the East Antarctic Ice Sheet is drained through the former, and then discharged into the western Ross Sea through the latter. David Drygalski is the largest outlet [...] Read more.

David Glacier and Drygalski Ice Tongue are massive glaciers in Victoria Land, Antarctica. The ice from the East Antarctic Ice Sheet is drained through the former, and then discharged into the western Ross Sea through the latter. David Drygalski is the largest outlet glacier in Northern Victoria Land, floating kilometers out to sea. The floating and grounded part of the David Glacier are the main focus of this article. During the XXI Italian Antarctic Expedition (2005–2006), within the framework of the National Antarctic Research Programme (PNRA), two GNSS stations were installed at different points: the first close to the grounding line of David Glacier, and the second approximately 40 km downstream of the first one. Simultaneous data logging was performed by both GNSS stations for 24 days. In the latest data processing, the kinematic PPP technique was adopted to evaluate the dominant diurnal components and the very small semi-diurnal variations in ice motion induced by the ocean tide and the mean ice flow rates of both GNSS stations. Comparison of the GNSS time series with predicted ocean tide calculated from harmonic coefficients of the nearest tide gauge stations, installed at Cape Roberts and Mario Zucchelli Station, highlight different local response of the glacier to ocean tide, with a minor amplitude of vertical motion at a point partially anchored at the bedrock close to the grounding line. During low tide, the velocity of the ice flow reaches its daily maximum, in accordance with the direction of seawater outflow from the fjord into the ocean, while the greatest daily tidal excursion generates an increase in the horizontal ice flow velocity. With the aim to extend the analysis in spatial terms, five COSMO-SkyMED Stripmap scenes were processed. The comparison of the co-registered offset tracking rates, obtained from SAR images, with the GNSS estimation shows good agreement. Full article

(This article belongs to the Special Issue Antarctic Remote Sensing Applications)

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15 pages, 3579 KiB

Open AccessArticle

A New Installation for Geomagnetic Field Monitoring at Talos Dome, a Remote Antarctic Site Away from Permanent Observatories

by Lucia Santarelli, Paolo Bagiacchi, Giovanni Benedetti, Domenico Di Mauro and Stefania Lepidi

Remote Sens. 2023, 15(2), 339; https://doi.org/10.3390/rs15020339 - 06 Jan 2023

Viewed by 2066

Abstract

An automatic geomagnetic station for monitoring the Earth’s magnetic field variations was installed in December 2020 at Talos Dome, a remote site on the Antarctic Plateau, about 300 km away from the permanent geomagnetic observatory at Mario Zucchelli Station (MZS). Designed and assembled [...] Read more.

An automatic geomagnetic station for monitoring the Earth’s magnetic field variations was installed in December 2020 at Talos Dome, a remote site on the Antarctic Plateau, about 300 km away from the permanent geomagnetic observatory at Mario Zucchelli Station (MZS). Designed and assembled at the laboratory of electronics of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) in Rome, this autonomous station is formed by a vector magnetometer specifically manufactured by Lviv Institute (Ukraine) for very low temperatures and a low-power system supplied by batteries charged by a wind generator and solar panel. Data, sampled at 1 Hz, are locally stored and can be downloaded once a year during the Antarctic summer expeditions. The goal was to integrate observatory data for better monitoring the geomagnetic field from an uncovered Antarctic area. In fact, it is well known that the distribution of geomagnetic observatories strongly favors the northern hemisphere, and each new instrumental installation in Antarctica should be considered as a useful attempt to balance the geomagnetic monitoring in the two hemispheres. The achieved goal was to obtain a long data series, keeping the station working even during the austral winter when the temperature can reach −60 °C; we recorded almost 11 months of data in one year and the station is still operating. Data from the new station, jointly with data from permanent observatories, improve the analysis of the magnetospheric dynamics and the ionosphere–magnetosphere coupling. Talos Dome, together with the Italian geomagnetic observatory at Mario Zucchelli Station and New Zealand geomagnetic observatory at Scott Base, constitutes a network along the 80°S geomagnetic parallel, which is interesting for studying the longitudinal propagation of geomagnetic signals of external origin. In this work we present the characteristics of the station and of the data it provides, with the aim of them for analysis in the framework of space weather. Full article

(This article belongs to the Special Issue Antarctic Remote Sensing Applications)

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16 pages, 5781 KiB

Open AccessArticle

New Evidence Supporting the Pacific Mantle Outflow: Hints from Crustal Magnetization of the Phoenix Plate

by Manuel Catalán and Yasmina M. Martos

Remote Sens. 2022, 14(7), 1642; https://doi.org/10.3390/rs14071642 - 29 Mar 2022

Cited by 3 | Viewed by 1485

Abstract

Magnetic contributions to the Earth’s magnetic field within the lithosphere are known as magnetic anomalies. Magnetic anomaly maps provide insight on magnetic properties of subsurface rock, geological structures, and plate tectonic history. A small number of studies have analyzed the Phoenix Plate based [...] Read more.

Magnetic contributions to the Earth’s magnetic field within the lithosphere are known as magnetic anomalies. Magnetic anomaly maps provide insight on magnetic properties of subsurface rock, geological structures, and plate tectonic history. A small number of studies have analyzed the Phoenix Plate based on magnetic anomaly data. These focused on its tectonic evolution. Here, we study the crustal magnetization of this region and combine the results with additional information from high-resolution bathymetry and complete Bouguer gravity anomalies. We analyzed the horizontal variation of the magnetization in two spectral domains: one that resolves the medium and long wavelengths magnetization components (20–200 km), and another one that focuses on short wavelengths (7–100 km). The obtained magnetization amplitude for the 20–200 km range reveals the presence of NE–SW and NW–SE high trends in magnetization. We attribute these alignments to induced magnetism. For the range of 7–100 km, the magnetization amplitude shows a progressive decrease towards the southern part of the Phoenix Plate. The obtained magnetization pattern and the integration with additional geophysical and geological information indicates a thermal demagnetization of the oceanic crust in the south, possibly caused by the Pacific mantle outflow present in this region. Full article

(This article belongs to the Special Issue Antarctic Remote Sensing Applications)

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