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The changes implemented in 2005 in the development strategies of Antarctic science carried out by Chile have had a positive impact on the scientific productivity of the Chilean Antarctic Science Program (PROCIEN). We analysed scientometric indicators from between 2009 and 2019. The bibliographic data were extracted from the Web of Science database using search query keywords. We used multiple correspondence analysis to identify specific trends and also network analyses of international collaboration in VOSviewer. The number of Antarctic science publications in Chile has gradually increased from 21 in 2009 to 95 in 2019. The rise in the number of articles was higher in journals for the first impact factor quartile. Research lines showing increased first-quartile impact factor papers corresponded to Antarctic ecosystems, biotechnology and geosciences. The main geographical domains in which such research activities have been carried out corresponded to in the South Shetland Islands and the Antarctic Peninsula. Fieldwork data are the main sources for the production of scientific articles, and there are three science platforms within which most of these papers concentrate. The diversification of funding sources, the implementation of improvements in the selection process and Chile's alignment with Scientific Committee on Antarctic Research programmes have contributed to improving the science that Chile has developed in Antarctica.

This study investigates strategies for calibration of surface mass balance (SMB) models in the Monte Sarmiento Massif (MSM), Tierra del Fuego, with the goal of achieving realistic simulations of the regional SMB. Applied calibration strategies range from a local single-glacier calibration to a regional calibration with the inclusion of a snowdrift parameterization. We apply four SMB models of different complexity. In this way, we examine the model transferability in space, the benefit of regional mass change observations and the advantage of increasing the complexity level regarding included processes. Measurements include ablation and ice thickness observations at Schiaparelli Glacier as well as elevation changes and flow velocity from satellite data for the entire study site. Performance of simulated SMB is validated against geodetic mass changes and stake observations of surface melting. Results show that transferring SMB models in space is a challenge, and common practices can produce distinctly biased estimates. Model performance can be significantly improved by the use of remotely sensed regional observations. Furthermore, we have shown that snowdrift does play an important role in the SMB in the Cordillera Darwin, where strong and consistent winds prevail. The massif-wide average annual SMB between 2000 and 2022 falls between −0.28 and −0.07 m w.e. yr−1, depending on the applied model. The SMB is mainly controlled by surface melting and snowfall. The model intercomparison does not indicate one obviously best-suited model for SMB simulations in the MSM.

Similar to the Patagonian Icefields, the Cordillera Darwin Icefield in Tierra del Fuego experienced important ice loss during the last decades. The difficult accessibility and the harsh weather conditions in that area result in scarce in-situ observations of climatic conditions and glacier mass balances. Under these challenging conditions, this study investigates calibration strategies of surface mass balance models in the Monte Sarmiento Massif, western Cordillera Darwin, with the goal to achieve realistic simulations of the regional surface mass balance in the period 2000-2022.We apply three calibration strategies ranging from a local single-glacier calibration to a regional calibration with and without the inclusion of a snowdrift parametrization. Furthermore, we apply four models of different complexity ranging from an empirical degree-day model to a fully-fledged surface energy balance model. This way, we examine the model transferability in space, the benefit of including regional mass change observations as calibration constraint and the advantage of increasing the model complexity regarding included processes. In-situ measurements comprise ablation stakes, ice thickness surveys and weather station records at Schiaparelli Glacier as well as elevation changes and flow velocity from satellite data for the entire study site. Performance of simulated surface mass balance is validated against geodetic mass changes and stake observations of surface melting.Results show that transferring mass balance models in space is a challenge, and common practices can produce distinctly biased estimates. The use of remotely sensed regional observations can significantly improve model performance. Increasing the complexity level of the model does not result in a clear improvement in our case where all four models perform similarly. Including the process of snowdrift, however, significantly increases the agreement with geodetic mass balances. This highlights the important role of snowdrift for the surface mass balance in the Cordillera Darwin, where strong and consistent westerly winds prevail.

Together with the Northern and the Southern Patagonian Icefield, the Cordillera Darwin Icefield (CDI) in Tierra del Fuego experienced strong ice loss during the last decades. In some areas the observed glacier retreat contrasts with findings of recent surface mass balance studies, which implies that the observed losses are partly caused by dynamic adjustments. However, the difficult accessibility of Patagonian glaciers and the harsh conditions result in scarce observational data of glacier mass balances, especially for the CDI. In the westernmost region of the CDI, Monte Sarmiento is located. It hosts an 83 km2 icefield, with Schiaparelli Glacier being the largest glacier, terminating in a proglacial lake.We focus on reproducing the local meteorological conditions using statistical downscaling of atmospheric reanalysis data to the study site as well as a linear model of orographic precipitation. Subsequently, we concentrate on a best representation of the surface mass balance (SMB) conditions on the local glaciers. For this purpose, we apply four melt models of different complexity: i) a positive degree-day model, ii) a simplified energy balance model using potential insolation, iii) a simplified energy balance model using the actual insolation (accounting for cloud cover, shading effects and diffuse radiation) and iv) a fully-fledged surface energy balance model. For the latter, we rely on the “COupled Snowpack and Ice surface energy and mass balance model in PYthon” (COSIPY). These models are calibrated on Schiaparelli Glacier (24.3 km2), which is the largest and best-studied glacier of the Monte Sarmiento Massif. Observational records comprise in-situ stake, thickness and meteorological measurements as well as remotely sensed elevation changes and flow velocities. After the melt model calibration, we apply them to other adjacent glacier basins and assess their performances against geodetic mass changes. This way, we want to answer the question if it is feasible to apply SMB models, calibrated for one single glacier, to surrounding glaciated areas under these unique climatic conditions. If a single-site calibration showed poor transferability properties, further remotely sensed observables will be considered in the calibration. This way we also hope to answer the question, which melt model can best reproduce the spatial variability in remotely sensed specific mass balances over a larger region.

The Antarctic Specially Protected Areas (ASPAs) are zones with restricted access to protect outstanding environmental, scientific, historic, aesthetic, or wilderness values adopted inside the Antarctic Treaty System. Meanwhile, in southern Patagonia, conservation initiatives are implemented by the state of Chile and private entities. However, both are considered unrepresentative. Our work evaluates the representativeness of the in situ conservation through a genetic approach of the moss Sanionia uncinata (Hedw.) Loeske among protected and neighboring free access areas in Maritime Antarctica and southern Patagonia. We discuss observed presence with both current and reconstructed past potential niche distributions (11 and 6 ka BP) in the Fildes Peninsula on King George Island. Results showed occurrence of several spatially genetic subpopulations distributed inside and among ASPA and free access sites. Some free access sites showed a higher amount of polymorphism compared with ASPA, having ancestry in populations developed in those places since 6 ka BP. The different spatial and temporal hierarchies in the analysis suggest that places for conservation of this species in Maritime Antarctica are not well-represented, and that some free access areas should be considered. This work represents a powerful multidisciplinary approach and a great challenge for decision-makers to improve the management plans and the sustainable development in Antarctica.

Yelcho Station is set on Doumer Island located in the southernmost section of Gerlache Strait between Anvers and Wienke Islands at the northwestern region of Antarctic Peninsula. This area is dominated by plutonic and volcanic deposits associated with the active margin developed during the Mesozoic and Cenozoic in the Antarctic Peninsula (e.g. Leat et al., 1995). Although Yelcho Station has been intensively visited since a few decades, the outcropping rocks have not been studied in detail. Furthermore, this location has hosted relevant contributions in the environmental and ecological sciences. We will present a detailed map (1:500) of the geological units outcropping in Yelcho Station based in fieldwork observations, which will be combined with drone and satellite images. Additionally, remote sensing spectral studies will be developed to support the geological mapping. This work will help to establish a geological baseline, which may serve for future studies in the area of Yelcho Station. This contribution will be a detailed geological study in the Antarctic Peninsula, which will also enhance our understanding of the geological units outcropping in Gerlache Strait. This material will also serve as an educational and outreach information for the polar community.Leat et al. (1995). Geological Magazine 132 (4), 399-412 (DOI: 10.1017/S0016756800021464).

King George Island is the largest one of the South Shetland Islands group distributed parallel to and separated by the Bransfield Strait of the northern tip of Antarctic Peninsula. The archipelago of the South Shetlands is mainly composed of the products of the active margin developed as a result of the subduction of the Phoenix Plate beneath the continental crust of the Antarctic Peninsula (e.g. Barker, 1982; Bastias et al., 2019). The lithologies are largely dominated by Mesozoic and Cenozoic sedimentary and volcanic successions that are cut by a few hypabyssal plutons. While some authors have suggested a southwest to northeast trend along the archipelago from older to younger magmatic activity (e.g. Haase et al., 2012), others have indicated that some of the magmatic events may have been recorded along the entire archipelago (e.g. Valanginian arc rocks; Bastias et al., 2019). Regardless, King George Island hosts an exceptional stratigraphical record of the Cenozoic period. Moreover, this island is mostly covered by an ice cap at the present day, which is commonly terminated with ice cliffs around much of the island. The southern edge of the island host Mesozoic and Paleogene successions, these rocks are dominated by volcanic and volcaniclastic units. The rocks in King George Island are generally young to the east and to the north ends. Cape Melville, the southeast extreme of the island, hosts the youngest sedimentary rocks known on the island: the Moby Dick Group (Birkenmajer, 1985).While several authors have presented local studies in the King George Island over the last three decades, an integrated assessment of the outcropping units in the entire island remains unexplored. A new geological map for King George Island will allow to update the current understanding of the stratigraphy of the South Shetland Islands, which will help to support not only the geological studies but also those focused on the environmental and paleontological record.Barker, 1982. Journal of the Geological Society 19, 787-801. (DOI: 10.1144/gsjgs.139.6.0787)Bastias et al. (2019). International Geology Review 62 (11), 1467-1484. (DOI: 10.1080/00206814.2019.1655669)Birkenmajer (1985). Bulletin Polish Academic Earth Sciences 33:15-23.Haase et al. (2012). Contributions to Mineralogy and Petrology 163, 1103-1119. (DOI: 10.1007/s00410-012-0719-7).

Cordillera Darwin in Tierra del Fuego (Chile) remains one of the least studied glaciated regions in the world. However, this region being one of very few terrestrial sites at this latitude in the Southern Hemisphere has the potential to provide key information on the effect of climate variability and climate change on the cryosphere at sub-polar mid-latitudes of the Southern Hemisphere. Glacier Schiaparelli is located at the northern side of the Cordillera Darwin draining the north side of Monte Sarmiento (2187 m asl). Despite being one of the largest glaciers in the Cordillera Darwin no previous in situ observation of its ice thickness had been made neither at this glacier nor at any other location in the Cordillera Darwin. Ice thickness is one of the fundamental parameters to understand glaciers dynamics, constrain ice dynamical modelling and predict glacier evolution. In April 2016 we performed the first successful ice thickness measurements using terrestrial ground- penetrating radar in the ablation area of Glacier Schiaparelli (Gacitúa et al., 2020), https://doi.org/10.1594/PANGAEA.919331. The measurements were made along a transect line perpendicular to the ice flow. Results show a valley shaped bedrock with a maximum ice thickness of 324 m within a distinct glacier trough. The bedrock is located below current sea level for 51 % of the transect measurements with a minimum of −158 m which illustrates that the local topography is subject to considerable glacier-related over-deepening.

Antarctica is well known to be highly susceptible to atmospheric and oceanic warming. However, due to the lack of long-term and in situ meteorological observations, little is known about the magnitude of the warming and the meteorological conditions in the intersection region between the Antarctic Peninsula (AP), the West Antarctic Ice Sheet (WAIS) and the East Antarctic Ice Sheet (EAIS). Here we present new stable water isotope data (δ18O, δD, d excess) and accumulation rates from firn cores in the Union Glacier (UG) region, located in the Ellsworth Mountains at the northern edge of the WAIS. The firn core stable oxygen isotopes and the d excess exhibit no statistically significant trend for the period 1980–2014, suggesting that regional changes in near-surface air temperature and moisture source variability have been small during the last 35 years. Backward trajectory modelling revealed the Weddell Sea sector, Coats Land and Dronning Maud Land (DML) to be the main moisture source regions for the study site throughout the year. We found that mean annual δ18O (δD) values in the UG region are negatively correlated with sea ice concentrations (SICs) in the northern Weddell Sea but not influenced by large-scale modes of climate variability such as the Southern Annular Mode (SAM) and the El Niño–Southern Oscillation (ENSO). Only mean annual d-excess values show a weak positive correlation with the SAM. On average annual snow accumulation in the UG region amounts to 0.245 m w.e. a−1 in 1980–2014 and has slightly decreased during this period. It is only weakly related to sea ice conditions in the Weddell Sea sector and not correlated with SAM and ENSO. We conclude that neither the rapid warming nor the large increases in snow accumulation observed on the AP and in West Antarctica during the last decades have extended inland to the Ellsworth Mountains. Hence, the UG region, although located at the northern edge of the WAIS and relatively close to the AP, exhibits rather stable climate characteristics similar to those observed in East Antarctica.

Understanding the distribution of airborne uranium is important because it can result in both chemical and radiological toxicity. Ice cores offer the most robust reconstruction of past atmospheric levels of toxic substances. Here we present the first sub-annually dated, continuously sampled ice core documenting change in U levels in the Southern Hemisphere. The ice core was recovered from the Detroit Plateau, northern Antarctic Peninsula, in 2007 by a joint Brazilian-Chilean-US team. It displays a significant increase in U concentration that coincides with reported mining activities in the Southern Hemisphere, notably Australia. Raw U concentrations in the Detroit Plateau ice core increased by as much as 102 between the 1980s and 2000s accompanied by increased variability in recent years. Decadal mean U concentrations increased by a factor of ∼3 from 1980 to 2007, reaching a mean of 205 pg/L from 2000 to 2007. The fact that other terrestrial source dust elements such as Ce, La, Pr, and Ti do not show a similar increase and that the increased U concentrations are enriched above natural crustal levels, supports an anthropogenic source for the U as opposed to a change in atmospheric circulation.

A 154 year-long, tree-ring based stable oxygen isotope time series (δ18OTRC) of the evergreen southern beech (Nothofagus betuloides) was established for the southernmost part of Patagonia. The trees grew on the terminal moraine system of the Schiaparelli Glacier (54.4°S) within the windward and hyper-humid zone of the Austral Andes. The annually resolved δ18OTRC record spans the common period 1861–2015 and is based on the analysis of five individually analyzed tree individuals showing a significant mean interseries correlation (r = 0.69). To date, this time series represents the worldwide southernmost chronology of tree-ring δ18OTRC. Variations of the δ18OTRC values are significantly correlated with hydroclimatic conditions, as derived from ERA-Interim reanalysis gridded data. Negative relationships between the δ18OTRC-series and relative humidity (rOct-Feb = −0.62, p

Resumen: Se genera el primer modelo de distribución potencial para los musgos Sanionia spp. en península Fildes, Shetland del Sur, Antártica, utilizando el algoritmo de máxima entropía (Maxent) para dos momentos del Holoceno. El modelo de distribución potencial de Sanionia spp. calibrado para el momento temporal presente (MDP S. Presente) se ejecuta para períodos de tiempo pasados 11 ka (MDP S. 11 ka) y 6 ka (MDP S. 6 ka). Conociendo que el nicho ecológico es un set de condiciones bióticas y abióticas en el cual la especie es capaz de mantenerse estable en tamaño poblacional, se utilizaron para la calibración del MDP S. Presente variables abióticas como la topografía y temperatura. Las variables topográficas son elevación, pendiente y exposición, construidas en base a un modelo de elevación digital del área libre de hielo de península Fildes. Para los MDP S. 11 ka y MDP S. 6 ka, se construyen las variables con los datos del modelo de elevación digital actual modificado según la reconstrucción de posición de la capa de hielo, el nivel del mar y valores de anomalías de temperatura obtenidos del testigo de hielo de la isla James Ross. El modelo de distribución potencial define que la probabilidad de presencia en península Fildes para el momento actual es de 29,5%, para el momento 6 ka la probabilidad de presencia es de 58,9% y para el momento 11 ka la probabilidad es de 69,9%. La probabilidad de presencia de Sanionia spp. en península Fildes ocurre con temperaturas entre los -2,4°C y los -3,0°C, alturas bajo los 130 m, pendientes bajo el 52% y exposiciones sur - este, sur- oeste y noroeste.

West Antarctica is well-known as a region that is highly susceptible to atmospheric and oceanic warming. However, due to the lack of long–term and in–situ meteorological observations little is known about the magnitude of the warming and the meteorological conditions in the region at the intersection between the Antarctic Peninsula (AP), the West Antarctic Ice Sheet (WAIS) and the East Antarctic Ice Sheet (EAIS). Here we present new stable water isotope data (δ18O, δD, d excess) and accumulation rates from firn cores in the Union Glacier (UG) region, located in the Ellsworth Mountains at the northern edge of the WAIS. The firn core stable oxygen isotope composition reveals no statistically significant trend for the period 1980–2014 suggesting that regional changes in near-surface air temperature have been small during the last 35 years. As for stable oxygen isotopes no statistically significant trend has been found for the d excess suggesting overall little change in the main moisture sources and the origin of precipitating air masses for the UG region at least since 1980. Backward trajectory modelling revealed the Weddell Sea sector to be the likely main moisture source region for the study site throughout the year. We found that mean annual δ–values in the UG region are correlated with sea ice concentrations in the northern Weddell Sea, but are not strongly influenced by large-scale modes of climate variability such as the Southern Annular Mode (SAM) and the El Niño–Southern Oscillation (ENSO). Only mean annual d excess values are weakly positively correlated with the SAM. On average snow accumulation in the UG region amounts to about 0.25 m w.eq. a−1 between 1980 and 2014. Mean annual snow accumulation has slightly decreased since 1980 (−0.001 m w.eq. a−1, p–value = 0.006). However, snow accumulation at UG is neither correlated with sea ice nor with SAM and ENSO confirming that the large increases in snow accumulation observed on the AP and in other coastal regions of Antarctica have not extended inland to the Ellsworth Mountains. We conclude that the UG region – located in the transition zone between the AP, the WAIS and the EAIS – is exhibiting rather East than West Antarctic climate characteristics.

Bryophytes are a major component of vegetation in ice-free coastal regions of Antarctica. Sanionia uncinata (Hedw.) Loeske is distributed from northern and central Maritime Antarctica to Marguerite Bay in the southern part of this biome where it occurs sparsely. Production of sporophytes is rare for S. uncinata in Antarctica, thus a high level of genetic uniformity among populations is expected (Lewis Smith, 1984). Several ice advances and retreats events in last thousands of years in Patagonia and Antarctica could have driven different processes of speciation at fine scale or triggered genetic differentiation among populations, leading to unique genetic populations. A few studies have analyzed the genetic structure of mosses in Antarctica, but none in Maritime Antarctica or in the nearby zones such as southern Patagonia. Based on Amplified Fragment Length Polymorphism (AFLP) and grouping analysis, we determined levels of intra/and inter-population genetic diversity of S. uncinata in sites of this region. The results revealed that gene diversity within populations was low and that populations did not have significant genetic differentiation. Also, no correlation was found between genetic variability and geographic distance (R2 = 0.031). However, we distinguished two groups of populations. One of them clustered populations with low values of genetic diversity. The other one was made out of populations showing much higher genetic diversity. Cluster 1 was the most geographically widely distributed covering populations from northern part of southern Patagonia to southern part of studied populations in Maritime Antarctica. Cluster 2 had the highest level of polymorphism, but spatially is very restricted to four populations in the Maritime Antarctica and southern Patagonia. We found substructures in some populations of the Maritime Antarctica such as in the Coppermine, Byers and Suffield populations. The underlying causes of this subdivision could be the asexual reproduction and significant abiotic factor affecting the presence of this moss species, but also the autoecious condition of this species. The importance of results is the concept of genetic connectivity among bioregions of South Patagonia and Antarctica suggesting additionally this interaction may have occurred repeatedly after the LGM, resulting in the vegetation that grows in Antarctica today.

The characterization of snow surface is essential to understand the Cryosphere dynamics of the Southern Patagonia of Chile. It becomes more important when we consider that is an area of difficult access due to its geography and extreme climatic conditions. Through the processing of orbitals images from sensors TM and OLI/TIRS, present on LANDSAT 5 and 8, respectively, and their subsequent classification by an algorithm of Maximum Likelihood Supervised Classification (CSMV) and an application of the threshold to Normalized-Difference Snow Index (NDSI), were obtained for each category binary maps with classes 1 (snow) and 0 (not snow). Images were vectorized and then areas corresponding to the snow cover, in square kilometers (km2), were calculated. The variation of snow cover was correlated to precipitation and temperature data (reanalysis II NCEP/NCAR) and with Oceanic Nino Index and Antarctic Oscillation Index. The variation of snow cover indicates a decline over the study period (June 2004 to June 2016), what could be associated with global warming or remote influence, for example, ENSO and Antarctic Oscillation. But there is no homogeneous pattern of cause and consequence between snow cover variations and remote phenomenon's occurrence.

The Antarctic Peninsula shows considerable spatial variability concerning its glaciological characteristics. It has also been subjected to severe climate changes, with reported glaciological consequences. However, such changes did not occur uniformly across the region. The present study aimed to characterize the glaciers of the Antarctic Peninsula geomorphologically and identify the spatial patterns of changes in their frontal position, generating an inventory of these features that will be part of the Global Land Ice Measurements from Space project. The study comprised the period between 1991 and 2015. We used ASTER imagery and ASTER GDEM and RAMP DEM digital elevation models to map the limits of glacial drainage basins. Landsat TM and ETM + data and the Antarctic Digital Database were used in areas not covered by ASTER images. We applied a supervised classification method to the satellite images to generate a mask of ice-free areas. The inventory of glaciers resulted in the delimitation of 1906 drainage basins between latitudes 61°S and 73°S, corresponding to an area of 476,507.83 km2. Ice-free areas occupied 5363.38 km2 (1% of the total). Between 2001 and 2015, 1339.68 km2 of ice was lost, corresponding to 1093 glaciers, while the area covered by glacier advance was estimated in 91.34 km2, corresponding to 255 glaciers, and 240 oscillating glaciers (gaining and losing ice mass). Thirty-nine percent of glaciers showed a slight retreat, 21% marked retreat, and 9% advanced during the period studied. The 16 ice shelves comprised an area of 137,677.16 km2, from which only 128,436.08 km2 remained until 2015. Eleven ice shelves experienced retreat during the period studied. We identified spatiotemporal variability patterns of the glaciers using statistical analysis by implementing empirical orthogonal functions (EOF), in which the first two EOFs represented approximately 87% of the space-time variability pattern of the glaciers. The glaciers classified as outlet glaciers (61%) were identified as the most sensitive to change, especially regarding frontal retreat. The glacial catchments classified as calving and floating were the most sensitive considering any change both in advance and retreat of their frontal area.

Here we present the results of a comprehensive glaciological investigation of Union Glacier (79°46' S/83°24' W) in the West Antarctic Ice Sheet (WAIS), a major outlet glacier within the Ellsworth Mountains. Union Glacier flows into the Ronne Ice Shelf, where recent models have indicated the potential for significant grounding line zone (GLZ) migrations in response to changing climate and ocean conditions. To elaborate a glaciological base line that can help to evaluate the potential impact of this GLZ change scenario, we installed an array of stakes on Union Glacier in 2007. The stake network has been surveyed repeatedly for elevation, velocity, and net surface mass balance. The region of the stake measurements is in near-equilibrium, and ice speeds are 10 to 33 m a−1. Ground-penetrating radars (GPR) have been used to map the subglacial topography, internal structure, and crevasse frequency and depth along surveyed tracks in the stake site area. The bedrock in this area has a minimum elevation of −858 m a.s.l., significantly deeper than shown by BEDMAP2 data. However, between this deeper area and the local GLZ, there is a threshold where the subglacial topography shows a maximum altitude of 190 m. This subglacial condition implies that an upstream migration of the GLZ will not have strong effects on Union Glacier until it passes beyond this shallow ice pinning point.

The location and intensity of the austral westerlies strongly influence southern hemisphere precipitation and heat transport with consequences for human society and ecosystems. With future warming, global climate models project increased aridity in southern mid-latitudes related to continued poleward contraction of the austral westerlies. We utilize Antarctic ice cores to investigate past and to set the stage for the prediction of future behaviour of the westerlies. We show that Holocene West Antarctic ice core reconstructions of atmospheric circulation sensitively record naturally forced progressive as well as abrupt changes. We also show that recent poleward migration of the westerlies coincident with increased emission of greenhouse gases and the Antarctic ozone hole has led to unprecedented penetration, compared with >100,000 years ago, of air masses bringing warmth, extra-Antarctic source dust and anthropogenic pollutants into West Antarctica. Copyright # 2012 John Wiley & Sons, Ltd.

Populations of both native higher Antarctic plants, Deschampsia antarctica and Colobanthus quitensis, increased during the last decades. However, for D. antarctica, previous population studies on the South Shetland Islands and the Antarctic Peninsula have been too sporadic, patchy, and methodologically different to allow general conclusions. Our aim was to compare sites with D.antarctica along a north–south latitudinal transect with an integral census method to assess the possible impact of climatic change on grass population dynamics. During two summer seasons (2009–2010), plant populations were censed on Fildes and Coppermine Peninsula and several localities on the west coast of the Antarctic Peninsula. Largest plant populations were found on Fildes Peninsula with vegetation cover (VC) of 44–46%. Six out of eleven stands of D. antarctica on Coppermine Peninsula were new records, with increasing plant number and VC (0.1–22%). In the Antarctic Peninsula, contrarily to our expectation, only at Forbes Point, D. antarctica VC was relatively high (ca. 2%) and a new stand of C. quitensis was found. At three previously reported sites, plants had disappeared. Our monitoring confirms that northern D. antarctica populations are expanding, but that this expansion is not continuous along the Antarctic Peninsula and inconsistent with the gradient of relative temperature increase in north–south direction. We suggest that other abiotic and biotic factors are influencing the colonization and expansion of vascular plants in this particular ecosystem.

Drastic changes were detected in glacial systems of the Antarctic Peninsula in the last decades. The observed phenomena comprise the disintegration of ice shelves, acceleration and thinning of glaciers, and retreat of glacier fronts. However, due to the lack of consistent systematic observations in particular of the higher parts of the glacial systems, it is difficult to predict further responses of the Antarctic Peninsula glaciers to climatic change. The present paper analyses spatial and temporal variations of changes in the dry-snow line altitude on the Antarctic Peninsula as extracted from a time series (1992–2005) of ERS-1/2 SAR and Envisat ASAR data. Upward changes in dry-snow line altitude were observed in general, and are attributed to extreme high-temperature events impacting the central plateaus of the Antarctic Peninsula and the increasing duration of warming periods. A mean decrease in dry-snow line altitude was detected on the west side of the peninsula and is identified as a response to recorded increase in precipitation and accumulation. These results validate the capability of SAR data for deriving superficial parameters of glaciers to be used as indicators of climatic changes in high-latitude regions where operational restrictions limit conventional meteorological observations.

Drastic changes have been detected in glacial systems of the Antarctic Peninsula in the last few decades and are well documented in numerous scientific publications. However, the spatial and temporal distribution of glacier changes on the Antarctic Peninsula remains largely restricted to ice fronts. To expand the current monitoring of a few glaciers, unevenly distributed along the peninsula, to a representative set, we developed a method to simplify the detection of boundaries between glacier zones using satellite SAR data. The evolution of glacier zones is greatly influenced by local and regional climatic and meteorological settings. Their variations in response to changes in energy or mass balance are considered as good indicators of climatic changes. In this paper, we describe the results of knowledge-based image analysis algorithms on test areas located at Trinity Peninsula and near Marguerite Bay. In general, the two analyzed areas show different patterns of glacier zone development. The bare-ice zone occurs mainly on glaciers located on the eastern side of Trinity Peninsula. Its upper boundary shows a good correlation with the mean summer air temperature. Finally, the position of the dry-snow line shows different spatial patterns of change in both study areas.

Changes in the ice fronts on the Antarctic Peninsula north of 70˚ S are currently being investigated through a comprehensive analysis of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) data as part of the international research initiative ‘Global land Ice Measurements from Space’ (GLIMS). Regional case studies are presented that cover a variety of glacial systems distributed over the northern Antarctic Peninsula and provide data on glacier front variations during the period 1986–2002. The results confirm a general trend of regional glacier front recession, but a range of different glacier variations are observed throughout the study area. Areas of predominant retreat are located in the northeastern and southwestern sectors, while stationary ice fronts characterize glacial behaviour on the northwestern coast of the peninsula. In addition, a significant increase in glacier recession is identified on James Ross Island, where retreat rates doubled during the period 1988–2001 compared to the previous investigation period, 1975–88. These observations are interpreted as being direct consequences of the rapidly changing climate in the region, which differentially affects the local accumulation and ablation patterns of the glacial systems.

This paper presents an inverse model for SAR backscatter X-band designed to snow and ice surfaces. The model inversion enables estimating the morphological characteristics of snow cover from SAR data. X Cosmo-Skymed sensor data was used in the experiment tested here for the region of Union Glacier - Antarctica. We observed a precision in determining the estimated size of snow grains about 94%. This result depicts the applicability of the analyzed model as an alternative way for extracting information from X-SAR data.

Union Glacier (79°46' S/83°24' W) in the West Antarctic Ice Sheet (WAIS), has been used by the private company Antarctic Logistic and Expeditions (ALE) since 2007 for their landing and commercial operations, providing a unique logistic opportunity to perform glaciological research in a vast region, including the Ice divide between Institute and Pine Island glaciers and the Subglacial Lake Ellsworth. Union glacier is flowing into the Ronne Ice Shelf, where future migrations of the grounding line zone (GLZ) in response to continuing climate and oceanographic changes have been modelled. In order to analyse the potential impacts on Union glacier of this scenario, we installed an array of stakes, where ice elevation, mass balance and ice velocities have been measured since 2007, resulting in near equilibrium conditions with horizontal displacements between 10 and 33 m yr−1. GPS receivers and three radar systems have been also used to map the subglacial topography, the internal structure of the ice and the presence of crevasses along surveyed tracks. The resulting radar data showed a subglacial topography with a minimum of 858 m below sea level, much deeper than estimated before. The below sea level subglacial topography confirms the potential instability of the glacier in foreseen scenarios of GLZ upstream migration during the second half of the XXI century.

The Antarctic Peninsula has exhibited some of the most spectacular changes observed in glacial systems in recent decades. The events include disintegration of ice shelves, acceleration and thinning of glaciers, variations in the limits between glacier facies, and retreat of glacier fronts. However, due to the lack of both consistent systematic observations of the glacial systems and information on their boundary conditions, it is difficult to accurately predict the contribution of Antarctic Peninsula glaciers to sea level rise and further responses of these ice masses to climatic and oceanographic changes. In this context, the activities of the GLIMS Regional Center for the Antarctic Peninsula and its network of international collaborators are based on the use of various types of Earth observation imagery, mainly optical and radar data. Although a complete glacier inventory is still lacking, we present the results of changes in glacier frontal positions and boundaries of glacier facies as well as links to dynamical adjustments for various locations in the Antarctic Peninsula’s ice masses. Evaluation of Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER) digital elevation models generated for the Antarctic Peninsula is also discussed.

Data collected from a voyage of RV Nathaniel B. Palmer to the Bellingshausen and Amundsen Seas during August–September 1993 are used to investigate the thickness distribution of sea ice and snow cover and the processes that influence the development of the first-year pack ice. The data are a combination of in situ and ship-based measurements and show that the process of floe thickening is highly dependent on ice deformation; in particular, rafting and ridging play important roles at different stages of floe development. Rafting is the major mechanism in the early stages of development, and core structure data show the mean thickness of individual layers of crystals to be only 0.12 m. Most ice 0.6 m having some surface deformation. Blocks within ridge sails are typically in the range 0.3–0.6 m thick, and ship-based observations estimate approximately 25% of the pack exhibits surface ridging. When corrected for biases in the observational methods, the data show that the dominant ice and snow thickness categories are >0.7 m and 0.2–0.5 m, respectively, and account for 40% and 36% of the surface area of the pack ice. Approximately 8% of the pack is open water. An estimate of the effects of ridging on the distribution of ice mass within the pack suggests that between 50 and 75% of the total mass is contained within the 25% of the pack that exhibits surface ridging.

An analysis of the main points and ideas arising during the fourth session "Climate Change: Op-portunities for scientific cooperation in the Region of Magallanes and Antarctica" of the International Colloquium "Climate Change in Magellan and Antarctic regions: Evidence and Challenges for the Future" are presented. These explored the availability and data needs, gaps and lack of knowledge, suggestions for topics and objectives in the planning of new research associated to understanding of climate change phenomenon. As general conclusions, have been recognized the greater value of signals and intensity of environmental changes, happening nowadays in special sites of this vast territory. At the same time, because of supposed richness of not well assessed regional biodiversity and of the uncertain climate change impacts’ on its species, an invaluable source of conditions are provided to contribute to the answering of global questions and to support advantageous scientific research in this less-polluted nature. In this context, was supported with priority the alternative of creating a network for research for climate change and its impact’s on biodiversity of Magellan and Antarctic Region. The Magellan and Antarctic Region territory is a singular area where environmental changes are occurring in an intensified level respect to other places of the Planet. This is not only an opportunity for the science to study causes and mechanisms of the phenomena here in the early warning area but also represent an opportunity to work together and use the scientific cooperation to contribute to the understanding and advancing of science. Se presenta un análisis de los principales contenidos e ideas surgidas durante la cuarta Sesión "Cambio Climático: Oportunidades para la cooperación científica en la Región de Magallanes y Antártica" del Coloquio Internacional "Cambio Climático en la Región de Magallanes y Antártica: Evidencia y Desafíos para el Futuro". Las presentaciones exploraron la disponibilidad y necesidades de datos, brechas y falta de conocimientos, las sugerencias de temas y objetivos en el planeamiento de nuevas investigaciones asociadas a la comprensión del fenómeno del cambio climático. Como conclusiones generales se ha reconocido el gran valor de las señales e intensidad de los cambios ambientales que se observan hoy en sitios particulares de esta vasta región geográfica. Al mismo tiempo se sugiere, debido a la supuesta riqueza de una no bien evaluada biodiversidad regional y de los inciertos impactos futuros del cambio climático sobre sus especies, que se cuenta con una invaluable fuente de condiciones que permiten la búsqueda de respuestas a preguntas globales y que permiten una ventajosa realización de investigación científica en esta menos contaminada naturaleza. En este contexto surgió con prioridad la alternativa de crear una red para fomentar la cooperación y la investigación del cambio climático y su impacto en la biodiversidad de la Región de Magallanes y Antártica Chilena. El territorio de la Región de Magallanes y Antártica Chilena es un área singular donde se producen intensos cambios ambientales respecto a otros lugares del Planeta, debidos al cambio climático. Esto representa para la ciencia no sólo una oportunidad de estudiar las causas y mecanismos del fenómeno aquí en el lugar de la alerta temprana, sino que también representa una oportunidad para trabajar unidos y usar la cooperación científica para contribuir al avance de la ciencia.

We analysed qualitative winter zooplankton samples, collected from the ocean surface, to test portions of proposed life-cycle models for Calanus propinquus. Nine zooplankton hauls were taken in the Bransfield Strait area during June 1996. Results show that C. propinquus is present in the ocean surface in winter. However, its presence seems to be related to ice coverage below 30%.