Antarctic Region Research Articles

Simultaneous observations of atmospheric vertical potential gradient from coastal Antarctic stations Bharati and Maitri

Simultaneous observations of the atmospheric electric potential gradient (PG) at Bharati and Maitri stations were studied from 2014 to 2016. A new regional diurnal pattern of fair-weather PG for the coastal Antarctic region, perhaps the ubiquitous characteristics of the PG for the coastal Antarctic region, has been identified. This pattern has a significant broad minimum around noon hours. It is around this time the wind speed is also maximum. The PG data of past years of Syowa, Vostok, and Carnegie Cruise were also used in this study. The surface wind distorts the fair-weather diurnal pattern of PG over Bharati more intensely than at Maitri. The katabatic wind effect on the PG at Bharati appears to be more intense than at Maitri. The topography and katabatic winds associated with the Lambert glacier could be the reason. The observation of Bipolar Air Ion Concentration (BAIC) suggests that the wind speed significantly affects the concentration by accumulation and dispersion. The concentration is maximum when the wind speed is minimum. As the air ion concentration controls the conductivity, the PG is expected to be minimum during these hours to produce an anomalous diurnal pattern in the PG at Bharati. Data quality is improved by measuring the PG with a field monitor at the surface level instead of at an elevated position. This study provides new hope in pursuing globally representative data of the PG for further investigations on the global thunderstorm activity and the solar-terrestrial weather relationship.

Usnea aurantiaco-atra (Jacq) Bory: Metabolites and Biological Activities.

Lichens are complex symbiotic associations between a fungus and an alga or cyanobacterium. Due to their great adaptability to the environment, they have managed to colonize many terrestrial habitats, presenting a worldwide distribution from the poles to the tropical regions and from the plains to the highest mountains. In the flora of the Antarctic region, lichens stand out due to their variety and development and are a potential source of new bioactive compounds. A phytochemical study of the Antarctic lichen Usnea aurantiaco-atra (Jacq) Bory was conducted with the intention of determining the most important metabolites. In addition, the cytotoxic and antioxidant activities of its extracts were determined. Cytotoxicity studies revealed that the hexane extract contains usnic acid as a majority metabolite, in addition to linoleic acid, ergosterols and terpenes, and demonstrates cytotoxic activity against an A375 melanoma cell line. On the other hand, the presence of total phenols in the extracts did not influence their antioxidant activity. U. aurantiaco-atra contains mainly usnic acid, although there are terpenes and ergosta compounds that could be responsible for its cytotoxic activity. The presence of phenols did not confer antioxidant properties.

Public support for Antarctic science: lessons from a national survey of Australians

AbstractWith the Antarctic region featuring more and more in discourse around anthropogenic climate change, understanding public support for research in the region is increasingly important. We examine public support for Antarctic science in Australia, drawing on findings from a nationally representative survey of just over 1000 adults conducted in 2021–2022. Key results reinforce earlier findings in other national contexts - for example, that older people and men are more likely to support Antarctic scientific research than younger people and women. They also reveal new information, including a correlation between particular sources of media coverage and support for Antarctic research. Our data have implications for where and how the public engagement efforts of government agencies and non-governmental organizations could most usefully be applied. While the survey is focused on Australia, it points to complexities around public support for Antarctic research that could be productively investigated in other national and in international contexts.

Marine distribution and habitat use by Snow Petrels Pagodroma nivea in East Antarctica throughout the non-breeding period

The relationships between flying Antarctic seabirds and their at-sea environments remain poorly understood, particularly outside of the breeding season. Improving our knowledge of how these marine predators use their habitat is a critical step towards conservation of these species. We tracked 27 adult Snow Petrels from two large breeding colonies in East Antarctica during the Austral winter (non-breeding period) – when they are primarily at sea away from their nesting sites. During this time, Snow Petrel habitat use was most associated with bathymetry (> 5000 m), low sea-surface height, relatively close distance to the southern boundary of the Antarctic Circumpolar Current, relatively close distance to the ice-edge, relatively high sea-ice concentration, and low sea-surface temperature. Individuals displayed various movement patterns: 20 birds occupied overlapping winter areas that ranged broadly (up to 2000 km) from their breeding sites. The remaining birds ventured far beyond their breeding sites – reaching a maximal distance from the colony of 5,268 km. One individual circumnavigated Antarctica. Daily activity patterns were related to day length, with peak activity occurring near dawn and dusk. Nocturnal activity increased from March until August/September. Key results reveal and depict Snow Petrel habitat maps for the non-breeding period in the East Antarctic region.

Occurrence and Trophic Transfer of Polychlorinated Naphthalenes (PCNs) in the Arctic and Antarctic Benthic Marine Food Webs.

Information about the occurrence and trophic transfer of polychlorinated naphthalenes (PCNs) in polar ecosystems is vital but scarce. In this study, PCNs were analyzed in benthic marine sediment and several biological species, collected around the Chinese polar scientific research stations in Svalbard in the Arctic and South Shetland Island in Antarctica. Total PCNs in biota ranged from 28 to 249 pg/g of lipid weight (lw) and from 11 to 284 pg/g lw in the Arctic and Antarctic regions, respectively. The concentrations and toxic equivalent (TEQ) of PCNs in polar marine matrices remained relatively low, and the compositions were dominated by lower chlorinated homologues (mono- to trichlorinated naphthalenes). Trophic magnification factors (TMFs) were calculated for congeners, homologues, and total PCNs in the polar benthic marine food webs. Opposite PCN transfer patterns were observed in the Arctic and Antarctic regions, i.e., trophic dilution and trophic magnification, respectively. This is the first comprehensive study of PCN trophic transfer behaviors in remote Arctic and Antarctic marine regions, providing support for further investigations of the biological trophodynamics and ecological risks of PCNs.

Mapping water content in drying Antarctic moss communities using UAS‐borne SWIR imaging spectroscopy

AbstractAntarctic moss beds are sensitive to climatic conditions, and both their survival and community composition are particularly influenced by the availability of liquid water over summer. As Antarctic regions increasingly face climate pressures (e.g., changing hydrology and heat waves), advancing capabilities to efficiently and non‐destructively monitor water content in moss communities becomes a key research priority. Because of the complexity induced by multiple micro‐climatic drivers and its fragility, tracking the evolution and responses of moss bed moisture requires monitoring methods that are non‐intrusive, efficient, and spatially significant, such as the use of unoccupied aerial systems (UAS). In this study, we combine a multi‐species drying laboratory experiment with short‐wave infrared (SWIR) spectroscopy analyses to first develop a Random Forest regression Model (RFM) capable of predicting Antarctic moss turf water content (~5% error). The RFM was then applied to UAS‐borne SWIR imaging data (900–1700 nm, <16 nm spectral resolution) of the moss beds at high spatial resolution (2 cm) across three sites in the vicinity of Casey Station, Antarctica. The sites differed in terrain, snow cover, and moisture availability to evaluate method capabilities under different conditions. Optimum RFM parameters and input variables (spectral indices and reflectance spectra) were determined. Maps of moss moisture were validated via acquiring moss spectra and water content (using sponges inserted into the moss turf) collected in situ, for which an exponential correlation (R2 = 0.72) was reported. RFM further allowed investigation of the influential spectral variables to model water content in moss and associated spectral water absorption features. We demonstrated that UAS‐borne SWIR imaging is a promising new tool to map and quantify water content in Antarctic moss beds. Hyperspectral mapping facilitates the exploration of the spatial variability of moss health and enables the creation of a baseline against which changes in these moss communities can be measured.

Occurrence of microplastics (MPs) in Antarctica and its impact on the health of organisms

Antarctica, and its surrounding environment, is considered untouched, and it is thought that it is free from microplastic (MP) pollution. However, recent studies and science projects have reported MPs in both water and sediment in the South Polar Regions. These reports state that MP pollution occurs in this region due to fishing, tourism, and research activities by the nearby countries, with natural circulation also part of it. The Antarctic Treaty System (ATS) has given attention to MP pollution and has initiated research on it. MPs are tiny plastic particles with a size of less than 5 mm. They have two types: 1. Primary MPs, which have been manufactured directly from various applications like cosmetics and scrubbing, etc. 2. Secondary MPs, which are generated by the photochemical degradation of large plastics. Although several studies have been done, there is a quite gap in our understanding of the concentration, characteristics, and impact of plastics on the ecosystem of the Antarctic Region. The impact of MP pollution in this region may be very high. The presence of MPs is a serious issue that is affecting not only the aquatic environment but also humans. It is an alarming situation that causes environmental damage. The main objective of this paper is to review MP introduction, occurrence in biotic and abiotic components, sources, harmful effects, and detection methods/techniques. This review highlights the various methodologies and analyses like density separation, microscope observation of MP’s properties Fourier-transform infrared spectroscopy (FTIR), and Raman spectrometer, respectively, and urges for more research in the future, giving several recommendations to maintain the pristine region near Antarctica. Highlights Antarctica is a pristine land and is separated from other continents Microplastics (MPs) are ubiquitous in nature with a size of < 5 mm These tiny particles are of two types primary MPs and secondary MPs MP pollution occurs in the Antarctic region due to fishing, tourism, and research activities MPs may be carcinogenic and act as endocrine disruptors in nature

Estimating summer sea ice extent in the Weddell Sea during the early 19th century

Abstract. Over the past 3 decades, discordant trends in sea ice extent have been observed between the Arctic and Antarctic regions. Arctic sea ice extent has been characterised by a rapid decline, whereas Antarctic sea ice extent, while highly variable interannually, has tended to increase. Climate models have so far failed to capture these trends. Coupled with the limited pre-1970 sea ice dataset, this poses a significant challenge to quantifying the mechanisms responsible for driving such trends. However, historical records from early Antarctic expeditions contain a wealth of information regarding the nature and concentration of sea ice. Such records have been underutilised, and their analysis may enhance our understanding of recent Antarctic sea ice variability. For the purpose of this study, nine records from eight Antarctic expeditions have been examined. Summer sea ice positions recorded during 1820–1843 have been compared to satellite observations from 1987–2017, as well as historical data for the period 1897–1917. Through analysis of these three time series, estimates for the northern limits of summer sea ice in the Weddell Sea during the early 19th century have been produced. The key findings of this study indicate a 19th century average core summer northernmost sea ice latitude in much of the Weddell Sea that was further north than during the modern era, with 19th century February having significantly more sea ice by all measures. However, late summer sea ice was most extensive in the early years of the 20th century.

Bridging the gap for ice–ocean–ecosystem processes: integrated observing system for the Ross Sea-far East Antarctic Region

Our understanding of cross-disciplinary connections for Antarctica’s role in the Earth system remains incomplete, especially around its coastal margins. The focus here is on sea-ice, oceanic, and atmospheric drivers in the joint Ross Sea-far East Antarctic Region (RSfEAR)—one which spans a large longitudinal range and connects a number of ice shelves and polynyas promoting sea-ice growth and underpinning a diverse and rich ecosystem. Here, we present a minireview of recent case studies and how these inform the design for a future integrated ocean–sea ice–atmosphere observing system. The review is built around five themes: i) regional setting, ii) recent studies in the region and current strategies, iii) gap analysis, iv) future observing system design, and v) wider implications for stakeholders.

International law, climate change and the Antarctic Treaty System: re-contemplating governance questions apropos of the mounting challenges

Abstract More than 60 years since it entered into force in 1961, the Antarctic Treaty is experiencing significant challenges. These challenges also affect its associated instruments known as the Antarctic Treaty System (ATS). These are mostly external dynamics that are increasingly challenging the ATS from outside of the Antarctic region. They encompass a spectrum of issues relating to global legal regimes and to what extent they are applicable in the Antarctic context. Climate change appears to be the most significant of these challenges, as the tangible planetary impacts of global warming and the perception of its urgency and seriousness by states have prompted additional challenges to the ATS. The physical changes that continue to be scientifically unveiled in the Antarctic are manifesting severe impacts on a planetary scale, and this fact has underscored the need for broader and more rapid international engagement within the Antarctic governance discourse. Nevertheless, the existing decision-making mechanisms compounded by the adversarial atmosphere within the ATS due to external factors have become challenges of themselves. Such challenges call for the re-contemplation and reassessment of the legal regime of the Antarctic in general, and the ATS in particular, to find ways forward for an otherwise historically effective international legal system. This paper utilizes both scientific and legal lenses to underscore the urgent need to achieve better communication between the ATS generally, the Antarctic Treaty Consultative Meetings specifically and the UN Framework Convention on Climate Change and Intergovernmental Panel on Climate Change regimes and to overcome the multiple barriers that stand in the way of achieving that objective.

The June 2022 extreme warm event in central West Antarctica

AbstractThe Antarctic surface mass balance has been shown to be sensitive to the impacts of atmospheric rivers (ARs), which bring anomalous amounts of both moisture and heat from lower latitudes poleward. Therefore, describing the characteristics of ARs and their intensity and frequency in the Antarctic regions by applying detection algorithms became a key method to evaluating their impacts on the surface mass balance and melting events. Several intense AR events have influenced Antarctica during the year 2022, and here we report an event with a peak on 10 June 2022 that was detected at 84°S, having a potential impact on West Antarctica. The extreme warm event originated in the Southern Pacific subtropical region and evolved towards the Southern Ocean, crossing the northern Antarctic Peninsula, before reaching as far as most inland regions in Antarctica, different from other typical ARs that are mostly restricted to the continental coast.

Monitoring of anthropogenic microplastic pollution in antarctic fish (emerald rockcod) from the Terranova Bay after a quarter of century

Monitoring the occurrence of microplastic contamination in the Antarctic area is the key to implement policy measures for waste regulations in the research stations. Antarctic fish Trematomus bernachii is a suitable species for establishing microplastic contamination and for investigating changes over time in the concentration and type of microplastics in the Antarctic region. In this paper a total of 78 fish, caught during the 37th Italian Antarctic expedition (2021–2022) in the Ross Sea (Antarctica) were analysed. Different microfibers and dyes were identified by Raman spectroscopy and the results were compared with those obtained for fish sampled in 1998. Differences in polymer type emerged with a predominance of synthetic fibers with respect to natural ones. These changes appear to be related to the increased human activities in the Antarctica over the last twenty years and highlights the need to improve the environmental sustainability of the numerous research stations operating throughout that area.

Examining the effect of ice dynamic changes on subglacial hydrology through modelling of a synthetic Antarctic glacier

Abstract Hydrologic pathways beneath ice sheets and glaciers play an important role in regulating ice flow. Antarctica has experienced, and will continue to experience, changes in ice dynamics and geometry, but the associated changes in subglacial hydrology have received less attention. Here, we use the GlaDS subglacial hydrology model to examine drainage evolution beneath an idealised Antarctic glacier in response to steepening ice surface slopes, accelerating ice velocities and subglacial lake drainages. Ice surface slope changes exerted a dominant influence, redirecting basal water to different outlet locations and substantially increasing channelised discharge crossing the grounding line. Faster ice velocities had comparatively negligible effects. Subglacial lake drainage results indicated that lake refilling times play a key role in drainage system evolution, with lake flux more readily accommodated following shorter refilling times. Our findings are significant for vulnerable Antarctic regions currently experiencing dynamic thinning since subglacial water re-routing could destabilise ice shelves through enhanced sub-shelf melting, potentially hastening irreversible retreat. These changes could also affect subglacial lake activity. We, therefore, emphasise that including a nuanced and complex representation of subglacial hydrology in ice-sheet models could provide critical information on the timing and magnitude of sea-level change contributions from Antarctica.

Radar‐Derived Snowfall Microphysical Properties at Davis, Antarctica

AbstractAntarctic precipitation remains poorly characterized and understood, especially within the boundary layer. This is due in part to a still‐limited amount of surface‐based remote sensing observations. A suite of cloud and precipitation remote‐sensing instruments including a W‐band cloud radar and a K‐band Micro Rain Radar (MRR) were used to characterize snowfall over Davis (69°S, 78°E). Surface snowfall events occurred when boundary layer wind speeds were weaker, temperatures were warmer, and relative humidity over ice higher than when virga were present. The presence of virga is associated with Föhn winds due to the location of Davis in the lee of an ice ridgeline. Dual wavelength ratio values from the summer indicate particle aggregation at temperatures of −14° to −10°C, consistent with observations made elsewhere, including in the Arctic. Riming frequency increases for temperatures above −10°C and reaches 6.5% at −3°C. No temperature dependence of rime mass fraction was found. Sublimation of snowfall mass aloft was 50% between the snow peak at 1.2 km and 205 m altitude, which occurs within CloudSat’s “blind zone.” Given the common prevailing wind direction and numerous ice ridgelines along much of the East Antarctic coastline, these Davis results can be used as a basis to further understand snowfall across the Antarctic region.

Increasing temperature-driven changes in life history traits and gene expression of an Antarctic tardigrade species.

The Antarctic region has been experiencing some of the planet's strongest climatic changes, including an expected increase of the land temperature. The potential effects of this warming trend will lead ecosystems to a risk of losing biodiversity. Antarctic mosses and lichens host different microbial groups, micro-arthropods and meiofaunal organisms (e.g., tardigrades, rotifers). The eutardigrade Acutuncus antarcticus is considered a model animal to study the effect of increasing temperature due to global warming on Antarctic terrestrial communities. In this study, life history traits and fitness of this species are analyzed by rearing specimens at two different and increasing temperatures (5°C vs. 15°C). Moreover, the first transcriptome analysis on A. antarcticus is performed, exposing adult animals to a gradual increase of temperature (5°C, 10°C, 15°C, and 20°C) to find differentially expressed genes under short- (1day) and long-term (15days) heat stress. Acutuncus antarcticus specimens reared at 5°C live longer (maximum life span: 686days), reach sexual maturity later, lay more eggs (which hatch in longer time and in lower percentage) compared with animals reared at 15°C. The fitness decreases in animals belonging to the second generation at both rearing temperatures. The short-term heat exposure leads to significant changes at transcriptomic level, with 67 differentially expressed genes. Of these, 23 upregulated genes suggest alterations of mitochondrial activity and oxido-reductive processes, and two intrinsically disordered protein genes confirm their role to cope with heat stress. The long-term exposure induces alterations limited to 14 genes, and only one annotated gene is upregulated in response to both heat stresses. The decline in transcriptomic response after a long-term exposure indicates that the changes observed in the short-term are likely due to an acclimation response. Therefore, A. antarcticus could be able to cope with increasing temperature over time, including the future conditions imposed by global climate change.

Spatial-temporal variations of one-year ice in Antarctic different regions, 1988–2020

In order to increase the comparability of Antarctic sea ice changes, we proposed a new method to quantitatively assess the spatial–temporal variation characteristics of Antarctic one-year ice based on daily Antarctic sea ice concentration data provided by the National Snow and Ice Data Center (NSIDC) from 1988 to 2020. According to the threshold value of 15% sea ice concentration, the definition of one-year ice and multiyear ice, we divided the Antarctic into 5 regions (seawater regions, stable one-year ice regions, one-year ice and seawater coexistence regions, multiyear ice regions, and one-year ice and multiyear ice coexistence regions) for 33 years and finally conducted the spatio-temporal analysis of the one-year ice in three regions (stable one-year ice regions, one-year ice and seawater coexistence regions, and one-year ice and multiyear ice coexistence regions). We examined the changes in sea ice parameters over 33 years. The results showed that from 1988 to 2020, in the stable one-year ice regions the Antarctic melt onset date had a slight delay trend with 0.2504 days year−1 and the melt end date had a slightly advance trend with 0.0524 days year−1, in the one-year ice and seawater coexistence regions the Antarctic annual average sea ice concentration had a weak decreasing trend with a rate of 0.0003/year (The maximal sea ice concentration is 0.238724 in 2010, and the minimal sea ice concentration is 0.166427 in 2019), in one-year ice and multiyear ice coexistence regions the multiyear ice increased at a rate of 0.0039 × 106 km2 and the annual melt index had a slight upward trend with 0.0022 × 108 km2 year−1.

Double‐Diffusive Layer and Meltwater Plume Effects on Ice Face Scalloping in Phase‐Change Simulations

AbstractAntarctic ice shelves are losing mass at increasing rates, yet the ice‐ocean interactions that cause significant ice loss are not well understood. A new approach of high‐resolution phase‐change simulations is used to model vertical ice melting into a stratified ocean. The ocean dynamics show complicated interplay between a turbulent buoyant meltwater plume and double‐diffusive layers, while the ice actively melts and changes topography. At room temperatures, the double‐diffusive layer thickness is closely linked to ice scalloping. At lower, more realistic ocean temperatures, the meltwater plume becomes prominent with a laminar‐to‐turbulent transition imprinting an indent on the melting ice. The double‐diffusive layer thickness is consistent with scaling prediction, while the real‐world application demonstrates reasonably good matching of the scaling prediction for some Antarctic regions. Our study is a key first step toward the future use of high‐resolution phase‐change fluid dynamics simulations to better understand Antarctic ice shelves in a changing climate.

Unusual Enhancement of the Optical Depth on the Continental Shelf Depth Latitudinal Variation in the Stratospheric Polar Vortex

The Antarctic ozone hole has attracted attention concerning global climate change. Breakthroughs regarding ozone observation methods and the formation principles of ozone holes have occurred. This study compared the slant column ozone obtained from SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) Level 1 optical spectroscopy data processed by QDOAS software with that reconstructed from SCIAMACHY Level 2 ozone data using geographic information to obtain the optical depth coefficients. The global distribution of optical depth coefficients reveals latitudinal homogeneity, whereas the distribution of coefficients in the polar regions reveals heterogeneity. This heterogeneity has an annual variation pattern, alternating between strong and weak distributions in the Arctic and Antarctic regions. It is most evident in the Palmer Peninsula of Antarctica, where the optical depth coefficients were significantly higher than those of the surrounding regions at the same latitude. This analysis excluded the atmospheric pressure influence and suggested the influence of the continental shelf depth. The protrusion of the continental shelf depth changes the optical depth coefficients owing to the geographical proximity of the Antarctic Palmer Peninsula to South America, which separates the Atlantic and Pacific Oceans in an east–west direction.

Biological Uptake, Water Mass Mixing and Scavenging Limit the Transport of Manganese‐Rich Waters From the East Antarctic Shelf

AbstractManganese (Mn) is an essential element involved in photosynthesis, yet its concentrations in Southern Ocean open waters are very low, arising from biological uptake and limited external inputs. At southern latitudes, waters overlying the Antarctic shelf are expected to have much higher Mn concentrations due to their proximity to external sources. In this study, we investigated the potential export of Mn‐rich Antarctic shelf waters toward depleted open Southern Ocean waters. Our results showed that while high Mn concentrations were observed over the shelf, biological uptake decreased dissolved Mn concentrations in surface waters north of the South Antarctic Circumpolar Current Front (<0.1 nmol kg−1), limiting its export. Conversely, mixing between Mn‐rich Antarctic Bottom Waters and Mn‐depleted Lower Circumpolar Deep Waters combined with oxidative and scavenging processes led to a decrease in dissolved Mn concentrations within bottom waters, with distance from the coast. Particulate Mn concentrations also showed a decreasing trend with distance from the coast. A comparison with other Antarctic coastal regions suggests this bottom water Mn removal may be widespread and that East Antarctica may be characterized by lower Mn concentrations compared to other regions. Still, subsurface dissolved Mn maxima (0.3–0.6 nmol kg−1) represented a potential reservoir for surface waters. We hypothesize that these high subsurface values result from external sources near the shelf. Overall, these results suggest that the moderate lateral export of trace metal‐enriched waters contributes to the extremely low and potentially limiting Mn concentrations previously reported further north in this Southern Ocean region.

Surface Displacement of Hurd Rock Glacier from 1956 to 2019 from Historical Aerial Frames and Satellite Imagery (Livingston Island, Antarctic Peninsula)

In the second half of the 20th century, the western Antarctic Peninsula recorded the highest mean annual air temperature rise in the Antarctic. The South Shetland Islands are located about 100 km northwest of the Antarctic Peninsula. The mean annual air temperature at sea level in this Maritime Antarctic region is close to −2 °C and, therefore, very sensitive to permafrost degradation following atmospheric warming. Among geomorphological indicators of permafrost are rock glaciers found below steep slopes as a consequence of permafrost creep, but with surficial movement also generated by solifluction and shallow landslides of rock debris and finer sediments. Rock glacier surface velocity is a new essential climate variable parameter by the Global Climate Observing System, and its historical analysis allows insight into past permafrost behavior. Recovery of 1950s aerial image stereo-pairs and structure-from-motion processing, together with the analysis of QuickBird 2007 and Pleiades 2019 high-resolution satellite imagery, allowed inferring displacements of the Hurd rock glacier using compression ridge-and-furrow morphology analysis over 60 years. Displacements measured on the rock glacier surface from 1956 until 2019 were from 7.5 m to 22.5 m and surface velocity of 12 cm/year to 36 cm/year, measured on orthographic images, with combined deviation root-mean-square of 2.5 m and 2.4 m in easting and northing. The inferred surface velocity also provides a baseline reference to assess today’s displacements. The results show patterns of the Hurd rock glacier displacement velocity, which are analogous to those reported within the last decade, without being possible to assess any displacement acceleration.