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Featured Application: This work gives indications for cleaning and preservation of ice cores, which will be drilled in Antarctica during the EU project Beyond EPICA Oldest Ice and provides general guidelines for ice drilling activities and preservation of ice cores. To reconstruct climate history of the past 1.5 Million years, the project: Beyond EPICA Oldest Ice (BEOI) will drill about 2700 m of ice core in East Antarctica (2021–2025). As drilling fluid, an aliphatic ester fluid, EstisolTM 140, will be used. Newly drilled ice cores will be retrieved from the drill soaked in fluid, and this fluid should be removed from the cores. Most of it will be vacuum-cleaned off in a Fluid Extraction Device and wiped off with paper towels. Based on our experiences in Greenland deep ice coring, most of the residual fluid can be removed by storing the cores openly on shelves in a ventilated room. After a week of "drying", the cores have a dry feel, handling them do not give "wet" gloves and they can easily be marked with lead pencils. This paper presents a theoretical investigation and some simple testing on the "drying" process. The rates of sublimation of ice and evaporation of fluid have been calculated at different temperatures. The calculations show that sublimation of the ice core should not occur, and that evaporation of fluid should be almost negligible. Our test results support these calculations, but also revealed significant fluid run-off and dripping, resulting in the removal of most of the fluid in a couple of days, independent of temperature and ventilation conditions. Finally, we discuss crucial factors that ensure optimal long-term ice core preservation in storage, such as temperature stability, defrosting cycles of freezers and open core storage versus storage of cores in insulated crates. [ABSTRACT FROM AUTHOR]

A large number of research stations have been established to provide members of Antarctic expeditions with logistical support. A previous study confirmed that the wind and solar energy resources of the Chinese Zhongshan Station, a coastal station located in an area of Lassmann Hills in East Antarctica, are highly synergetic and complementary. Considering the demand for a renewable energy power supply in Zhongshan Station, this paper introduces a hybrid energy system with wind–solar–diesel–battery co-generation used as a power supply scheme. Based on the 2015 climate data for Zhongshan Station, the wind–solar resources, conventional energy system, and annual diesel consumption of the station area were analyzed. The annual electrical load demand of each building in the station area was quantitatively expounded. Compared with the original power supply system, and combined with the analysis results of the thermal load and electrical load demands of the station, an objective function based on the requirements of economy, reliability, and environmental protection was presented. According to the constraint conditions of the heat energy and electrical energy load balance in the station area, a multi-objective scheduling strategy for the system was designed. Finally, the effects of this scheduling strategy were analyzed under three different application scenarios. The results indicated that the annual load demand was significantly lower than before the scheduling, and that a 50% reduction in diesel consumption could be achieved, demonstrating that the multi-objective scheduling strategy proposed in this paper could achieve optimal energy scheduling and management of the renewable hybrid energy system. [ABSTRACT FROM AUTHOR]

The focus of this paper is on COVID-19, the December 2019 dated respiratory epidemic or infection that has ravaged most, if not all, of the world's 253 "countries" (consisting of 194 independent nation-states, 55 dependent-states, Antarctica, and 3 other territories). Readers of this paper should be aware of at least three facts. First, as of January 2022, the submission date of this paper, COVID-19 continues to impact the world, although to a much lesser extent, given the protection afforded by the mRNA vaccines, the boosters, and the antiviral medications (e.g., oseltamivir, penciclovir, acyclovir, Paxlovid, etc.). Second, the paper should be regarded as being inconclusive in both its outlook and its list of references; it provides, at best, an intermediary account of the continuing COVID-19 pandemic. Third, like the Spanish Flu of 1918, it is speculated that the COVID-19 pandemic will not endure beyond three years and will conclude as an endemic problem by, hopefully, early 2023. Therefore, the paper is partitioned into three sections which, respectively, address the infection's three phases: epidemic (initial infection), pandemic (worldwide infection) and endemic (pervasive but nonlife-threatening infection) phases. The lessons learned from the range of decisions made throughout the COVID-19 phases should help to inform and better prepare the world for future pathogens and deadly diseases. [ABSTRACT FROM AUTHOR]

In Antarctica, it is extremely difficult to organise medical evacuations in winter. Antarctic physicians are often alone and must be prepared to perform surgery and dentistry, even if they are not specialists. This scoping review summarises epidemiological data on the types of surgical procedures performed in Antarctica and identifies gaps in the literature in this area. We searched PubMed and Google Scholar, without language restriction, for papers published between 1 January 1904, and 1 February 2022. Of the 35 papers on 12 Antarctic programs, very few were retrospective observational epidemiological studies; the majority were medical reports. The search identified 41 surgical procedures or reasons for surgical consultation, 19 different reasons for medical evacuations, and 12 causes of death that may have required surgical management. The diagnostic classifications used and the prevalence of each reported surgical speciality were heterogeneous. The most cited specialities were orthopaedics, dentistry, and digestive surgery. Telemedicine was integrated into on-site care or medical evacuation decisions. The current literature is poor, and most studies do not apply to surgical issues. The heterogeneous data collection methodologies limit their interpretation. A standardised diagnostic classification and detailed and systematic epidemiological registers will help define the contours of surgical management in Antarctica. [ABSTRACT FROM AUTHOR]

The article presents a study on the new Digital Elevation Model (DEM) of the Antarctic Peninsula based on the Advanced Spaceborne Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) data. The study used a method to improve the ASTER GDEM dataset that will create a DEM with a 100 meter (m) pixel which is suitable for glaciological applications. The new DEM is evaluated using the Ice, Cloud and land Elevation Satellite (ICESat)-derived elevations.

The H2 18 O abundance in present-day water for the atmospheric and oceanic components. For the atmosphere, it is found that the model reproduces the observed spatial distribution and relationships to climate variables with some merit, though limitations following our approach are highlighted. Indeed, we obtain the main gradients with a robust representation of the Rayleigh distillation but caveats ap pear in Antarctica and around the Mediterranean region due to model limitation. For the oceanic component, the agreement between the modelled and observed distribution of water δ2 18 O abundance in present-day water for the atmospheric and oceanic components. For the atmosphere, it is found that the model reproduces the observed spatial distribution and relationships to climate variables with some merit, though limitations following our approach are highlighted. Indeed, we obtain the main gradients with a robust representation of the Rayleigh distillation but caveats ap pear in Antarctica and around the Mediterranean region due to model limitation. For the oceanic component, the agreement between the modelled and observed distribution of water δ18O is found to be very good. Mean ocean surface latitudinal gradients are faithfully reproduced as well as the mark of the main intermediate and deep water masses. This opens large prospects for the applications in paleoclimatic context. [ABSTRACT FROM AUTHOR]

The article offers information on the study conducted by the authors related to the Southern Ocean including a thermodynamic active ice self, with reference to Weddell Sea. It states that the study aims at the importance of sea ice and ice shelf processes in the Southern Ocean, a coupled ocean circulation sea ice cavity model based on the Regional Ocean Model System (ROMS) is used in a periodic circumpolar domain with enhanced resolution in the Weddell Sea.

The article discusses the atmospheric measurement of ozone layer boundary in Terra Nova Bay, Antarctica through unmanned aircraft system (UAS). It mentions that the UAS, which was provided with several instruments needed such as flight sensors, autopilot and communication, was created by Cloud Cap Technologies Inc. It states that the global positioning system (GPS) data gathered were passed to the United States Antarctic Program Data Coordination Center (USAP-DCC) for restoration and access.

The article presents a study of the assimilation of observed ice concentration and freeboard information into a global coupled ocean-sea-ice model using an Ensemble Kalman Filter system. It evaluates the efficiency and impact of the data assimilation on ice concentration. Results demonstrate that the simulated Antarctic and Arctic sea-ice are improved using the assimilation of synthetic ice concentration data.

Optically thin ice clouds play an important role in polar regions due to their effect on cloud radiative impact and precipitation on the surface. Cloud bases can be detected by lidar-based ceilometers that run continuously and therefore have the potential to provide basic cloud statistics including cloud frequency, base height and vertical structure. Despite their importance, thin clouds are however not well detected by the standard cloud base detection algorithm of most ceilometers operational at Arctic and Antarctic stations. This paper presents the Polar Threshold (PT) algorithm that was developed to detect optically thin hydrometeor layers (optical depth τ ⩾ 0.01). The PT algorithm detects the first hydrometeor layer in a vertical attenuated backscatter profile exceeding a predefined threshold in combination with noise reduction and averaging procedures. The optimal backscatter threshold of 3×10-4 km-1 sr-1 for cloud base detection was objectively derived based on a sensitivity analysis using data from Princess Elisabeth, Antarctica and Summit, Greenland. The algorithm defines cloudy conditions as any atmospheric profile containing a hydrometeor layer at least 50m thick. A comparison with relative humidity measurements from radiosondes at Summit illustrates the algorithm's ability to significantly differentiate between clear sky and cloudy conditions. Analysis of the cloud statistics derived from the PT algorithm indicates a year-round monthly mean cloud cover fraction of 72% at Summit without a seasonal cycle. The occurrence of optically thick layers, indicating the presence of supercooled liquid, shows a seasonal cycle at Summit with a monthly mean summer peak of 40 %. The monthly mean cloud occurrence frequency in summer at Princess Elisabeth is 47 %, which reduces to 14% for supercooled liquid cloud layers. Our analyses furthermore illustrate the importance of optically thin hydrometeor layers 25 located near the surface for both sites, with 87% of all detections below 500m for Summit and 80% below 2 km for Princess Elisabeth. These results have implications for using satellite-based remotely sensed cloud observations, like CloudSat, that may be insensitive for hydrometeors near the surface. The results of this study highlight the potential of the PT algorithm to extract information in polar regions about a wide range of hydrometeor types from measurements by the robust and relatively low-cost ceilometer instrument. [ABSTRACT FROM AUTHOR]

Climate changes induced by stratospheric ozone depletion over Antarctica have been recognized as an important consequence of the recently observed Southern Hemisphere atmospheric circulation. Here we present evidences that the Brazilian coast (Southwestern Atlantic) may have been impacted from both winds and sea surface temperature changes derived from this process. Skeleton analysis of massive coral species living in shallow waters off Brazil are very sensitive to air-sea interactions, and seem to record this impact. Growth rates of Brazilian corals show a trend reversal that fits the ozone depletion evolution, confirming that ozone impacts are far reaching and potentially affect coastal ecosystems in tropical environments. [ABSTRACT FROM AUTHOR]

The article offers information on the development of a 1200-year proxy index of reconstruction of volcanic eruptions that is based on sulphate records found in ice cores of Antarctic and Greenland. It states that processes in the reconstruction include calibration with satellite aerosol optical depth (AOD), identification of new categories of eruptions, and specification of power shortwave scaling. It adds the introduction of estimate on the particle size that affect the stratospheric aerosols.

This paper documents the occurrence of the genus Umbilicaria in the Argentine Islands–Kyiv Peninsula region of the Graham Coast in the maritime Antarctic. The presence of seven Umbilicaria species (U. africana, U. antarctica, U. aprina, U. decussata, U. kappenii, U. nylanderiana and U. umbilicarioides) in the ice-free areas of the Argentine Islands–Kyiv Peninsula region were confirmed. The species of U. africana and U. aprina are documented from the studied region for the first time. This study moves the southern distribution limit of U. africana about 300 km to the south: to the Argentine Islands–Kyiv Peninsula region. The distribution maps of Umbilicaria species for the studied region and maritime Antarctica are prepared. [ABSTRACT FROM AUTHOR]

Climate change has resulted in more frequent occurrences of extreme events, such as flooding and heavy snowfall, which can have a significant impact on densely populated or industrialised areas. Numerical models are used to simulate and predict these extreme events, enabling informed decision-making and planning to minimise human casualties and to protect costly infrastructure. LISFLOOD is an integrated hydrological model underpinning the European Flood Awareness System and Global Flood Awareness System (EFAS and GloFAS, respectively), developed by the Copernicus Emergency Management Service (CEMS). The CEMS_SurfaceFields_2022 dataset is a new set of high-resolution surface fields at 1 and 3 arcmin resolution (approximately 2 and 6 km at the Equator, respectively) based on a wide variety of high-resolution and up-to-date data sources. The 1 arcmin fields cover Europe, while the surface fields at 3 arcmin cover the global land surface (excluding Antarctica). The dataset encompasses (i) catchment morphology and river networks, (ii) land use, (iii) vegetation cover type and properties, (iv) soil properties, (v) lake information, and (vi) water demand. This paper details the complete workflow used to generate the CEMS_SurfaceFields_2022 fields, including the data sources and methodology. Whilst created together with upgrades to the open source LISFLOOD code, the CEMS_SurfaceFields_2022 fields can be used independently for a wide range of applications, including as input to hydrological, Earth system, or environmental models or for carrying out general analyses across spatial scales, ranging from global and regional levels to local levels (especially useful for regions outside Europe), expected to improve the accuracy, detail and realism of applications. [ABSTRACT FROM AUTHOR]

The meridional overturning circulation (MOC) in the ocean is a key player in the global climate system, while continental topography provides an essential backdrop to the system. In this study, we design a series of coupled model sensitivity experiments to investigate the influence of various mountain ranges on the global thermohaline circulation. The results highlight the influence of the Tibetan Plateau (TP) on the global thermohaline circulation. It emerges as a requisite for establishing the Atlantic MOC (AMOC) and a determining factor for the cessation of the Pacific MOC (PMOC). Additionally, the Antarctic continent plays a vital role in facilitating the TP to form the AMOC. While the formation of the AMOC cannot be attributed to any single mountain range, the TP alone can inhibit the PMOC's development. By modifying the global hydrological cycle, the TP is likely to have been crucial in molding the global thermohaline circulation. This paper presents quantitative evaluation of the role of different continental mountains in shaping the global meridional overturning circulation. The Tibetan Plateau is likely to have been crucial in molding the global thermohaline circulation. [ABSTRACT FROM AUTHOR]

The Ilyarachninae are a diverse and widely distributed subfamily of the asellote family Munnopsidae. This paper describes nine new deep-sea species from two Ilyarachninae genera, Ilyarachna and Notoapais, from the southwestern Pacific, namely from New Zealand and the east coast of Australia. Ilyarachna aculeatus n. sp., Ilyarachna brucei n. sp., Ilyarachna franki n. sp., Ilyarachna mclayi n. sp., Ilyarachna pacifica n. sp., Ilyarachna sami n. sp., Ilyarachna taranui n. sp. and Notopais chathamensis n. sp. are described from New Zealand waters, while Notopais likros n. sp. is described from off the east coast of Australia. Additionally, a redescription of Notopais spinosa from the Balleny Islands, Antarctica, and a revised key to the Ilyarachna and Notopais species from the southwest Pacific are included, and the distribution, affinities, and diagnostic characters of the new species are discussed. [ABSTRACT FROM AUTHOR]

The thickness of the Antarctic ice sheet is a crucial parameter for inferring glacier mass and its evolution process. In the literature, the gravity method has been proven to be one of the effective means for estimating ice sheet thickness. And it is a preferred approach when direct measurements are not available. However, few gravity inversion methods are valid in rugged terrain areas with undulating observation surfaces (UOSs). To solve this problem, this paper proposes an improved high-precision 3D density interface inversion method considering terrain and UOSs simultaneously. The proposed method utilizes airborne gravity data at their flight altitudes, instead of the continued data yield from the unstable downward continuation procedure. In addition, based on the undulating right rectangular prism model, the large reliefs of the terrain are included in the iterative inversion. The proposed method is verified on two synthetic examples and is successfully applied to real data in East Antarctica. [ABSTRACT FROM AUTHOR]

Increasing snow accumulation over the Antarctic Ice Sheet may mitigate future sea level rise. However, current estimates of mitigation potential are poorly constrained due to limited records of past variability. We present an annually resolved reconstruction of Antarctic snow accumulation from 1801 to 2000 CE, employing a paleoclimate data assimilation methodology to integrate ice core records with a multi‐model ensemble of climate simulations. Our reconstruction correlates well with instrumental reanalysis, and we find that Antarctic accumulation rates increased over the 20th‐century, resulting in a modest amount (∼1 mm) of sea level mitigation. Mitigation is primarily driven by an accelerating trend since around 1970. Our results contrast with previous mitigation estimates of ∼10–12 mm; this discrepancy is due to poorly constrained baseline estimates of 19th‐century accumulation in East Antarctica. Our reconstruction suggests that the uncertainty of future sea level mitigation from increasing Antarctic accumulation has been underestimated. Plain Language Summary: Ice loss from Antarctica causes sea level to rise, but Antarctica can also mitigate sea level rise if snowfall on the continent increases faster than the ice loss. There is not currently a consensus on whether Antarctica will contribute to or mitigate sea level rise in the coming century, due to a lack of Antarctic snowfall records. In this paper, we merge information from ice core records with climate models to reconstruct annual Antarctic snowfall from 1801 to 2000. We find that snowfall on Antarctica increased during the 20th‐century, but only had a modest counteracting effect of 1 mm on sea level rise in the 20th‐century, much less than a previous estimate of 10 mm. The large discrepancy is due to uncertainty in East Antarctic accumulation in the 19th‐century. The potential for Antarctica to mitigate sea level is uncertain, affecting projections for future sea level rise. Key Points: Antarctic accumulation reconstruction using paleoclimate data assimilation finds modest (∼1 mm) 20th‐century sea level mitigationWe find similar 20th‐century trends to previous work; lower sea level mitigation (1 vs. 10 mm) is due to the 19th‐century baselineUncertainty in past East Antarctic accumulation limits confidence in future projections of Antarctic sea level mitigation [ABSTRACT FROM AUTHOR]

In January 1964, temperature measurements were made on Lake Joyce, in the Taylor Valley, Antarctica. The lake had a salt concentration gradient that stabilised it against mixing, much like other lakes in the area, but the maximum water temperature was about 0.8°C, much less than the temperature of the other lakes as reported in earlier published papers. [ABSTRACT FROM AUTHOR]

The article focuses on the database that have time-referenced sea ice draft values from upward looking sonar (ULS) measurements in the Weddell Sea, Antarctica. It says that the ice sea draft data can be utilized to infer the ice thickness, which were collected in 1990-2008. it states that the database includes measurements from 13 locations and generated from over 3.7 million measurements of sea ice draft. Moreover, the data processing and quality control were discussed in detail.

The article presents a study on the formulation and application of a three-dimensional (3D) ice sheet-shelf model in Antartica. It states that the model has been used for paleoclimatic studies and designed for long-term applications of continental-scale. It also discusses ice retreat sensitivity at the last deglaciation to basal sliding coefficients.

This paper aims to solve the limitations of traditional gravity physical property inversion methods such as insufficient depth resolution and difficulties in parameter selection, by proposing an improved 3D gravity inversion method based on deep learning. The deep learning network model is established using the fully convolutional U-net network. To enhance the generalization ability of the sample set, the large-scale training set and test set are generated by the random walk, based on the forward theory. Founded on the traditional loss function's definition, this paper introduces an improvement incorporating a physical constraint to measure the degree of data fitting between the predicted and the real gravity data. This improvement significantly boosted the accuracy of the deep learning inversion method, as verified through both a single model and an intricate combination model. Finally, we applied this improved inversion method to the gravity data from the Gamburtsev Subglacial Mountains in the interior of East Antarctica, obtaining a comprehensive 3D crustal density structure. The results provide new evidence for the presence of a dense crustal root situated beneath the central Gamburtsev Province near the Gamburtsev Suture. [ABSTRACT FROM AUTHOR]

Surface solar radiation (SSR) is an essential factor in the flow of surface energy, enabling accurate capturing of long-term climate change and understanding of the energy balance of Earth's atmosphere system. However, the long-term trend estimation of SSR is subject to significant uncertainties due to the temporal inhomogeneity and the uneven spatial distribution of in situ observations. This paper develops an observational integrated and homogenized global terrestrial (except for Antarctica) station SSR dataset (SSRIH station) by integrating all available SSR observations, including the existing homogenized SSR results. The series is then interpolated in order to obtain a 5 ∘ × 5 ∘ resolution gridded dataset (SSRIH grid). On this basis, we further reconstruct a long-term (1955–2018) global land (except for Antarctica) SSR anomaly dataset with a 5 ∘ × 2.5 ∘ resolution (SSRIH 20CR) by training improved partial convolutional neural network deep-learning methods based on 20th Century Reanalysis version 3 (20CRv3). Based on this, we analysed the global land- (except for Antarctica) and regional-scale SSR trends and spatiotemporal variations. The reconstruction results reflect the distribution of SSR anomalies and have high reliability in filling and reconstructing the missing values. At the global land (except for Antarctica) scale, the decreasing trend of the SSRIH 20CR (- 1.276 ± 0.205 W m -2 per decade) is smaller than the trend of the SSRIH grid (- 1.776 ± 0.230 W m -2 per decade) from 1955 to 1991. The trend of the SSRIH 20CR (0.697 ± 0.359 W m -2 per decade) from 1991 to 2018 is also marginally lower than that of the SSRIH grid (0.851 ± 0.410 W m -2 per decade). At the regional scale, the difference between the SSRIH 20CR and SSRIH grid is more significant in years and areas with insufficient coverage. Asia, Africa, Europe and North America cause the global dimming of the SSRIH 20CR , while Europe and North America drive the global brightening of the SSRIH 20CR. Spatial sampling inadequacies have largely contributed to a bias in the long-term variation of global and regional SSR. This paper's homogenized gridded dataset and the Artificial Intelligence reconstruction gridded dataset (Jiao and Li, 2023) are both available at 10.6084/m9.figshare.21625079.v1. [ABSTRACT FROM AUTHOR]

Antarctica is of great importance in terms of global warming, the sustainability of resources, and the conservation of biodiversity. However, due to 99.66% of the continent being covered in ice and snow, geological research and geoscientific study in Antarctica face huge challenges. Geophysical surveys play a crucial role in enhancing comprehension of the fundamental structure of Antarctica. This study used bibliometric analysis to analyze citation data retrieved from the Web of Science for the period from 1982 to 2022 with geophysical research on Antarctica as the topic. According to the analysis results, the amount of Antarctic geophysical research has been steadily growing over the past four decades as related research countries/regions have become increasingly invested in issues pertaining to global warming and sustainability, and international cooperation is in sight. Moreover, based on keyword clustering and an analysis of highly cited papers, six popular research topics have been identified: Antarctic ice sheet instability and sea level change, Southern Ocean and Sea Ice, tectonic activity of the West Antarctic rift system, the paleocontinental rift and reorganization, magmatism and volcanism, and subglacial lakes and subglacial hydrology. This paper provides a detailed overview of these popular research topics and discusses the applications and advantages of the geophysical methods used in each field. Finally, based on keywords regarding abrupt changes, we identify and examine the thematic evolution of the nexus over three consecutive sub-periods (i.e., 1990–1995, 1996–2005, and 2006–2022). The relevance of using geophysics to support numerous and diverse scientific activities in Antarctica becomes very clear after analyzing this set of scientific publications, as is the importance of using multiple geophysical methods (satellite, airborne, surface, and borehole technology) to revolutionize the acquisition of new data in greater detail from inaccessible or hard-to-reach areas. Many of the advances that they have enabled be seen in the Antarctic terrestrial areas (detailed mapping of the geological structures of West and East Antarctica), ice, and snow (tracking glaciers and sea ice, along with the depth and features of ice sheets). These valuable results help identify potential future research opportunities in the field of Antarctic geophysical research and aid academic professionals in keeping up with recent advances. [ABSTRACT FROM AUTHOR]

Global warming has become one of the most prominent global issues, and Antarctic ice sheet is one of the indicator of global climate change. Satellite imagery has become an important means of monitoring the changes in Antarctic ice sheet. Due to the high overlap of satellite imaging swaths, the existing Antarctica images have the disadvantages of long period of imagery acquisition, large temporal difference among the mosaic images, and low utilization of satellite resource. This paper proposes a satellite imaging mission planning method for fast Antarctica coverage. First, the imaging time window is forecasted within the specified imaging time range to obtain all the visible time windows of the imaging satellite to Antarctica. Then, taking the selection of each time window and the satellite swing angle in each time window as decision variables, and the satellite attitude maneuver ability as constraint, an imaging mission model including two objective functions with minimum number of imaging time windows and the maximum coverage rate is established. To solving the proposed multi-objective optimization model, an improved real-binary hybrid LMOCSO (large-scale multi-objective optimization based on a competitive swarm optimizer) is proposed in this paper. Finally, a simulation experiment was performed using Gaofen-3 satellite to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The concept of multiple scaling regimes in temperature time series is examined, with emphasis on the question whether or not a mono-scaling model can be rejected from the data at hand. A model with only one regime is simpler and is preferred if this explains the observed variability. Our analysis of spectra from reconstructed air temperature from Greenland and Antarctica ice cores shows that a scale break around centennial time scales is evident for the last glacial period, but not for the Holocene. Nor by analysing a number of late Holocene multiproxy temperature reconstructions can a significant scale break be identified. Our results indicate that a mono-scaling model cannot be rejected as a null model for the Holocene climate up to at least millennial time scales, although it can be rejected for the glacial climate state. The scale break observed from the glacial time ice core records is likely caused by the influence of Dansgaard-Oeschger events and teleconnections to the Southern Hemisphere on centennial time scales. From our analysis we conclude that the two-regime model is not sufficiently justified for the Holocene to be used for temperature prediction on centennial time scales. [ABSTRACT FROM AUTHOR]

The article presents a study on the intercomparison of ozone profiles in Antarctica to quantify ozone depletion or recovery. The study employed Infrared Atmospheric Sounding Interferometer (IASI) instrument, global positioning system (GPS) receiver, MetOp satellite collected at McMurdo Station, Antarctica, during the Concordiasi campaign. Results reveal that overestimation of ozone cannot be explained by the IASI to measure the high gradient because of zone depletion process.

The article presents a study which investigated a discrepancy between in-situ and remote measurements of bromine oxide (BrO) during Antarctic enhancements. The study measured BrO using a ground-based remote-sensing spectrometer at Halley in Antarctica. It notes that a large discrepancy between BrO in-situ and remote-sensing measurements existed during the Antarctic enhancements episodes when the gas laid in a surface layer having similar thickness with that of the boundary layer.

The article presents a study which compiles measurements of tropospheric gas-phase and aerosol chemistry in Arctic and Antarctic regions. The study used the Internet, meteorological data, and ozone data during the International Geophysical Year in 1958. Excluded data from the compilation include meteorological data, snow-chemistry data, and carnbon dioxide (CO2).

Using fluorescence spectrometry to map autofluorescence of chlorophyll (Chl) and tryptophan (Trp) versus depth in polar ice cores in the US National Ice Core Laboratory, we found that the Chl and Trp concentrations often showed an annual modulation of up 5 to 25%, with peaks at depths corresponding to local summers. Using epifluorescence microscopy (EFM) and flow cytometry (FCM) triggered on 670 nm fluorescence (red) to study microbes from unstained melts of the polar ice, we inferred that picocyanobacteria may have been responsible for the red fluorescence in the cores. Micron-size bacteria in all ice melts from 2 Arctic and 6 Antarctic sites showed FCM patterns of o scattering and of red vs. orange fluorescence (interpreted as due to Chl vs. phycoery-thrin (PE)) that bore similarities to patterns of cultures of unstained picocyanobacteria Prochlorococcus and Synechococcus. Concentrations in ice from all sites were low but measurable at ∼ 1 to ∼ 10³ cells cm-3. Calibrations showed that FCM patterns of mineral grains and volcanic ash could be distinguished from microbes with high efficiency s by triggering on scattering instead of by red fluorescence. Average Chl and PE autofluorescence intensities showed no decrease per cell with time during up to 150 000 yr of storage in glacial ice. Taking into account the annual modulation of ∼ 25% and seasonal changes of ocean temperatures and winds, we suggest that picocyanobacteria are wind-transported year-round from warmer ocean waters onto polar ice. Ice cores o offer the opportunity to study evolution of marine microbes over ∼ 300 million generations by analyzing their genomes vs. depth in glacial ice over the last 700 000 yr as frozen proxies for changes in their genomes in oceans. [ABSTRACT FROM AUTHOR]

Reconstructions of past atmospheric methane concentrations are available from ice cores from both, Greenland and Antarctica. The difference observed between the two polar methane concentration levels is a valuable additional parameter which allows to constrain the geographical location of the responsible methane sources. Here we present new high-resolution methane records from the North Greenland Ice Core Project (NGRIP) and the European Project for Ice Coring in Antarctica (EPICA) Dronning Maud Land (EDML) ice cores covering Termination 1, the Last Glacial Maximum, and parts of the last glacial back to 32 000 years before present. Due to the highresolution records the synchronisation between the ice cores from NGRIP and EDML is considerably improved and the interpolar concentration difference of methane is determined with unprecedented precision and temporal resolution. Relative to the mean methane concentration, we find a rather stable positive interpolar difference throughout the record with its minimum value of 3.7±0.7% between 21 900-21 200 years before present, which is higher than previously estimated in this interval close to the Last Glacial Maximum. This implies that Northern Hemisphere boreal wetland sources were never completely shut off during the peak glacial. Starting at 21 000 years before present, i.e. severval millenia prior to the transition into the Holocene, the relative interpolar difference becomes even more positive and stays at a fairly stable level of 6.5±0.8% during Termination 1. We hypothesise that the anti-correlation observed in the monsoon records from the Northern and Southern Hemispheres induces a methane source redistribution within lower latitudes, which could explain parts of the variations in the interpolar difference. [ABSTRACT FROM AUTHOR]

Cyanobacteria form diverse communities and are important primary producers in Antarctic freshwater environments, but their geographic distribution patterns in Antarctica and globally are still unresolved. There are however few genomes of cultured cyanobacteria from Antarctica available and therefore metagenomeassembled genomes (MAGs) from Antarctic cyanobacteria microbial mats provide an opportunity to explore distribution of uncultured taxa. These MAGs also allow comparison with metagenomes of cyanobacteria enriched communities from a range of habitats, geographic locations, and climates. However, most MAGs do not contain 16S rRNA gene sequences, making a 16S rRNA gene-based biogeography comparison difficult. An alternative technique is to use large-scale k-mer searching to find genomes of interest in public metagenomes. This paper presents the results of k-mer based searches for 5 Antarctic cyanobacteria MAGs from Lake Fryxell and Lake Vanda, assigned the names Phormidium pseudopriestleyi FRX01, Microcoleus sp. MP8IB2.171, Leptolyngbya sp. BulkMat.35, Pseudanabaenaceae cyanobacterium MP8IB2.15, and Leptolyngbyaceae cyanobacterium MP9P1.79 in 498,942 unassembled metagenomes from the National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA). The Microcoleus sp. MP8IB2.171 MAG was found in a wide variety of environments, the P. pseudopriestleyi MAG was found in environments with challenging conditions, the Leptolyngbyaceae cyanobacterium MP9P1.79 MAG was only found in Antarctica, and the Leptolyngbya sp. BulkMat.35 and Pseudanabaenaceae cyanobacterium MP8IB2.15 MAGs were found in Antarctic and other cold environments. The findings based on metagenome matches and global comparisons suggest that these Antarctic cyanobacteria have distinct distribution patterns ranging from locally restricted to global distribution across the cold biosphere and other climatic zones. [ABSTRACT FROM AUTHOR]

Long-term monitoring projects are becoming more than ever crucial in assessing the effects of climate change on marine communities, especially in Antarctica, where these changes are expected to be particularly dramatic. Detailed studies of the Antarctic benthos are in fact particularly important for a better understanding of benthos dynamics and potential climate-driven shifts. Here, due to the extreme fragility of benthic communities, non-destructive techniques represent the best solution in long-term monitoring programs. In this paper we report new results from 2017, 2018, 2019 photogrammetric campaigns within the Italian National Antarctic Research Program (PNRA). A new protocol of data acquisition and multi-temporal processing that provides co-registered 3D point clouds between the three years without control points nor direct georeferencing methods is presented. This is achieved by adding a level of image understanding leveraging semantic segmentation with convolutional neural network (CNN) of the benthic features. Slow growing (estimated less than a mm per year) organisms, such as Corallinales (Rhodophyta algae), represent a natural stable pattern, leveraged to automatically orient in the same reference system the photogrammetric surveys of different epochs. This approach is also proved to be effective in improving the orientation of adjacent strips acquired within the same campaign. Within the paper an in depth analysis of the achieved results shows the effectiveness of the implemented procedure. [ABSTRACT FROM AUTHOR]

The NASA Atmospheric Tomography Mission (ATom) completed four seasonal deployments (August 2016, February 2017, October 2017, May 2018), each with regular 0.2–12 km profiling by transecting the remote Pacific Ocean and Atlantic Ocean basins. Additional data were also acquired for the Southern Ocean, the Arctic basin, and two flights over Antarctica. ATom in situ measurements provide a near-complete chemical characterization of the ∼ 140 000 10 s (80 m by 2 km) air parcels measured along the flight path. This paper presents the Modeling Data Stream (MDS), a continuous gap-filled record of the 10 s parcels containing the chemical species needed to initialize a gas-phase chemistry model for the budgets of tropospheric ozone and methane. Global 3D models have been used to calculate the Reactivity Data Stream (RDS), which is comprised of the chemical reactivities (production and loss) for methane, ozone, and carbon monoxide, through 24 h integration of the 10 s parcels. These parcels accurately sample tropospheric heterogeneity and allow us to partially deconstruct the spatial scales and variability that define tropospheric chemistry from composition to reactions. This paper provides a first look at and analysis of the up-to-date MDS and RDS data including all four deployments (Prather et al., 2023, 10.7280/D1B12H). ATom's regular profiling of the ocean basins allows for weighted averages to build probability densities for the key species and reactivities presented here. These statistics provide climatological metrics for global chemistry models, e.g., the large-scale pattern of ozone and methane loss in the lower troposphere and the more sporadic hotspots of ozone production in the upper troposphere. The profiling curtains of reactivity also identify meteorologically variable and hence deployment-specific hotspots of photochemical activity. Added calculations of the sensitivities of the production and loss terms relative to each species emphasize the few dominant species that control the ozone and methane budgets and whose statistical patterns should be key model–measurement metrics. From the sensitivities, we also derive linearized lifetimes of ozone and methane on a parcel-by-parcel basis and average over the basins, providing an observational basis for these previously model-only diagnostics. We had found that most model differences in the ozone and methane budgets are caused by the models calculating different climatologies for the key species such as O 3 , CO, H 2 O, NO x , CH 4 , and T , and thus these ATom measurements make a substantial contribution to the understanding of model differences and even identifying model errors in global tropospheric chemistry. [ABSTRACT FROM AUTHOR]

Antarctic Treaty Consultative Parties are entitled to participate in consensus-based governance of the continent through the annual Antarctic Treaty Consultative Meetings. To acquire consultative status, an interested Party must demonstrate "substantial research activity," but no agreed mechanism exists to determine whether a Party has fulfilled this criterion. Parties have generally demonstrated substantial research activity with the construction of a research station, as suggested within the Treaty itself. However, this largely demonstrates logistical capacity, rather than research activity, and often results in major and persistent impacts on Antarctic terrestrial environments. Our study found that national investment in Antarctic infrastructure, estimated by the number of bed spaces at stations, was not a reliable indicator of scientific output. Therefore, we investigated metrics to evaluate research activity directly, and identified both the overall number of Antarctic papers and the proportion of national scientific output these represented as meaningful metrics. Such metrics could (1) demonstrate a nation's level of research activity in Antarctica or (2) help Consultative Parties assess the level of research activity undertaken by a Party seeking to acquire consultative status. Our data showed that, even without land-based Antarctic infrastructure, Canada, Denmark and Switzerland may have reasonable grounds to demonstrate "substantial research activity" on a level comparable with existing Consultative Parties. The use of these metrics may help dispel any perceived requirement for the establishment of a research station to reach consultative status, by putting a greater emphasis on generation of scientific research outputs rather than construction of Antarctic infrastructure. [ABSTRACT FROM AUTHOR]

Flavobacterium sp. AUG42 is a cellulase-producing bacterium isolated from the Antarctic oligochaete Grania sp. (Annelida). In this work, we report that AUG42 produces a glycoside hydrolase cocktail with CMCase, PASCase and cellobiase activities (optimum pHs and temperatures ranging from 5.5 to 6.5 and 40 to 50 °C, respectively). The time-course analyses of the bacterial growth and cellulase production showed that the cocktail has maximal activity at the stationary phase when growing at 16 °C with filter paper as a cellulosic carbon source, among the tested substrates. The analyses of the CAZome and the identification of secreted proteins by shotgun Mass Spectrometry analysis showed that five glycoside hydrolyses are present in the bacterial secretome, which probably cooperate in the degradation of the cellulosic substrates. Two of these glycoside hydrolyses may harbor putative carbohydrate binding modules, both with a cleft-like active site. The cellulolytic cocktail was assayed in saccharification experiments using carboxymethylcellulose as a substrate and results showed the release of glucose (a fermentable sugar) and other reducing-sugars, after 24 h incubation. The ecological relevance of producing cellulases in the Antarctic environment, as well as their potential use in the bio-refinery industry, are discussed. [ABSTRACT FROM AUTHOR]

Remote sensing is a very powerful tool that has been used to identify, map and monitor Antarctic features and processes for nearly one century. Satellite remote sensing plays the main role for about the last five decades, as it is the only way to provide multitemporal views at continental scale. But the emergence of small consumer-grade unoccupied aerial vehicles (UAVs) over the past two decades has paved the way for data in unprecedented detail. This has been also verified by an increasing noticeable interest in Antarctica by the incorporation of UAVs in the field activities in diversified research topics. This paper presents a comprehensive review about the use of UAVs in scientific activities in Antarctica. It is based on the analysis of 190 scientific publications published in peer-reviewed journals and proceedings of conferences which are organised into six main application topics: Terrestrial, Ice and Snow, Fauna, Technology, Atmosphere and Others. The analysis encompasses a detailed overview of the activities, identifying advantages and difficulties, also evaluating future possibilities and challenges for expanding the use of UAV in the field activities. The relevance of using UAVs to support numerous and diverse scientific activities in Antarctica becomes very clear after analysing this set of scientific publications, as it is revolutionising the remote acquisition of new data with much higher detail, from inaccessible or difficult to access regions, in faster and cheaper ways. Many of the advances can be seen in the terrestrial areas (detailed 3D mapping; vegetation mapping, discrimination and health assessment; periglacial forms characterisation), ice and snow (more detailed topography, depth and features of ice-sheets, glaciers and sea-ice), fauna (counting penguins, seals and flying birds and detailed morphometrics) and in atmosphere studies (more detailed meteorological measurements and air-surface couplings). This review has also shown that despite the low environmental impact of UAV-based surveys, the increasing number of applications and use, may lead to impacts in the most sensitive Antarctic ecosystems. Hence, we call for an internationally coordinated effort to for planning and sharing UAV data in Antarctica, which would reduce environmental impacts, while extending research outcomes. [ABSTRACT FROM AUTHOR]

The largest uncertainty in projections of future sea-level change results from the potentially changing dynamical ice discharge from Antarctica. Basal ice-shelf melting induced by a warming ocean has been identified as a major cause for additional ice flow across the grounding line. Here we derive dynamic ice-sheet response functions for basal ice-shelf melting for four different Antarctic drainage regions using experiments from the Sea-level Response to Ice Sheet Evolution (SeaRISE) intercomparison project with five different Antarctic ice-sheet models. Under the assumptions of linearresponse theory we project future ice-discharge for each model, each region and each of the four Representative Concentration Pathways (RCP) using oceanic temperatures from 19 comprehensive climate models of the Coupled Model Intercomparison Project, CMIP-5, and two ocean models from the EU-project Ice2Sea. The uncertainty in the climatic forcing, the oceanic response and the ice-model response is combined into an uncertainty range of future Antarctic ice-discharge induced from basal ice-shelf melt. The uncertainty range we derived for the Antarctic contribution to global sea-level rise from 1992 to 2011 is in full agreement with the observed contribution for this period if we use the three ice-sheet models with an explicit representation of ice-shelf dynamics and account for the time delayed warming of the oceanic subsurface compared with the surface air temperature. The median of the additional ice-loss for the 21st century (Table 6) is 0.07m (66%-range: 0.02-0.14m; 90%-range: 0.0-0.23m) of global sea-level equivalent for the low-emission RCP-2.6 scenario and 0.09m (66 %-range: 0.04-0.21 m; 90 %-range: 0.01-0.37 m) for the strongest RCP-8.5 if models with explicit ice-shelf representation are applied. These results were obtained using a time delay between the surface warming signal and the subsurface oceanic warming as observed in the CMIP-5 models. Without this time delay the values increase to 0.09m (66 %-range: 0.04-0.17 m; 90 %-range: 0.02-0.25 m) for RCP-2.6 and 0.15m (66 %- range: 0.07-0.28 m; 90 %-range: 0.04-0.43 m) for RCP-8.5. Our results are scenario dependent which is most visible in the upper percentiles of the distribution, i.e. highest. contributions to sea level rise. All probability distributions, as provided in Fig. 12, are highly skewed towards high values. The applied ice-sheet models are coarse-resolution with limitations in the representation of grounding-line motion. However, we find the main uncertainty to be introduced by the external forcing to the ice-sheets, i.e. the climatic and oceanic uncertainty dominate. The scaling coefficients for the four different drainage basins provide valuable information for further assessments of future Antarctic ice discharge. [ABSTRACT FROM AUTHOR]

We present estimates of mixed layer net community oxygen production (N) and gross oxygen production (G) of the Bellingshausen Sea in March and April 2007. N was derived from oxygen-to-argon (O2 / Ar) ratios; G was derived using the dual-delta method from triple oxygen isotope measurements. In addition, O2 profiles were collected at 253CTD stations. N is often approximated by the biological oxygen air-sea exchange flux (Fbio) based on the O2 / Ar supersaturation, assuming that significant horizontal or vertical fluxes are absent. Here, we show that the effect of vertical fluxes alone can account for Fbio values <0 in large parts of the Bellingshausen Sea towards the end of the productive season, which could be mistaken to represent net heterotrophy. Thus, improved estimates of mixed-layer N can be derived from the sum of Fbio, Fe (entrainment from the upper thermocline during mixed-layer deepening) and Fv (diapycnal eddy diffusion across the base of the mixed layer). In the Winter Sea Ice Zone (WSIZ), the corresponding correction results in a small change of Fbio =(30±17)mmolm-2 d-1 to N =(34±17)mmolm-2 d-1. However, in the permanent open ocean zone (POOZ), the original Fbio value of (-17±10)mmolm-2 d-1 gives a corrected value for N of (-2±18)mmolm-2 d-1. We hypothesize that in the WSIZ enhanced water column stability due to the release of freshwater and nutrients from sea-ice melt may account for the higher N-value. These results stress the importance of accounting for physical biases when estimating mixed layer-marine productivity from in situ O2 / Ar ratios. [ABSTRACT FROM AUTHOR]

In this paper, we study the problem of extracting trends from time series data involving missing values. In particular, we investigate a general class of procedures that impute the missing data and then extract trends using seasonal-trend decomposition based on loess (STL), where loess stands for locally weighted smoothing, a popular tool for describing the regression relationship between two variables by a smooth curve. We refer to them as the imputation-STL procedures. Two results are obtained in this paper. First, we settle a theoretical issue, namely the connection between imputation error and the overall error from estimating the trend. Specifically, we derive the bounds for the overall error in terms of the imputation error. This subsequently facilitates the error analysis of any imputation-STL procedure and justifies its use in practice. Second, we investigate loess-STL, a particular imputation-STL procedure with the imputation also being performed using loess. Through both theoretical arguments and simulation results, we show that loess-STL has the capacity of handling a high proportion of missing data and providing reliable trend estimates if the underlying trend is smooth and the missing data are dispersed over the time series. In addition to mathematical derivations and simulation study, we apply our loess-STL procedure to profile radiosonde records of upper air temperature at 22 Antarctic research stations covering the past 50 years. For purpose of illustration, we present in this paper only the results for Novolazaravskaja station which has temperature records with more than 8.4% dispersed missing values at 8 pressure levels from October/1969 to March/2011. [ABSTRACT FROM AUTHOR]

The article discusses research by Tim Naish and Ross Powell investigating climate change through the study of sediment cores extracted from the sea bed of the West Antarctic ice sheet (WAIS). The goal of climate scientists is to ascertain what the WAIS looked like during the Pliocene epoch. Topics include the difficulty in obtaining sediment cores, a description of the cores' contents, and what the cores reveal about projected climate changes.

The article states that a research team led by Eric Steig of the University of Washington has discovered that the warming trend once thought confined to the western edge of the Antarctic Peninsula has spread beyond the peninsula and over most of West Antarctica. This warming trend has allowed for the encroachment of flora and has resulted in the outflow of Adélie penguins.

The article presents a study which investigates on the centrifugal ice microtome (ICM) of atmospheric measurement of carbon dioxide (CO2) on air trapped in polar ice cores. The study used a new dry extraction technique with the combination of a new five gas analytical systems that show significant improvements with respect to current systems. The study shows that gas analytical parts show a factor with two higher precision compared to the corresponding part of the existing system.

The article presents a study which focuses on the use of Challenging Minisatellite Payload (CHAMP) Global Positioning System (GPS) radio occultation (RO) data in the investigation of temperature trends in Antarctica. The seasonal temperature trends are examined at 100 hectopascals and 500 hectopascals pressure levels. Variations in the temperature at spatial and temporal domains are highlighted.

The article discusses the technical description and the result regarding the use of autonomous surface ozone monitors to study ozone in Antarctica. It provides an overview of the development of the monitoring systems which where deployed in a network around the Weddell Sea sector of coastal Antarctica with a transect up onto the Antarctic Plateau. It also discusses the use of a modified version of the commercial 2B Technologies Inc. 10 Model 202 instrument to measure ozone mixing ratios.

The article discusses the dataset for high resolution numerical ice sheet modeling of the Antarctic Ice Sheet. It states that the dataset addresses inconsistencies on ice thickness and basal topography including novel interpolation schemes. It talks about the data processing executed to produce the datasets which includes the masks and ice sheet configuration datasets, the surface air temperature, the accumulation, and the geothermal heat flux.

Cyanobacteria in polar environments face environmental challenges, including cold temperatures and extreme light seasonality with small diurnal variation, which has implications for polar circadian clocks. However, polar cyanobacteria remain underrepresented in available genomic data, and there are limited opportunities to study their genetic adaptations to these challenges. This paper presents four new Antarctic cyanobacteria metagenome-assembled genomes (MAGs) from microbial mats in Lake Vanda in the McMurdo Dry Valleys in Antarctica. The four MAGs were classified as Leptolyngbya sp. BulkMat.35, Pseudanabaenaceae cyanobacterium MP8IB2.15, Microcoleus sp. MP8IB2.171, and Leptolyngbyaceae cyanobacterium MP9P1.79. The MAGs contain 2.76 Mbp - 6.07 Mbp, and the bin completion ranges from 74.2-92.57%. Furthermore, the four cyanobacteria MAGs have average nucleotide identities (ANIs) under 90% with each other and under 77% with six existing polar cyanobacteria MAGs and genomes. This suggests that they are novel cyanobacteria and demonstrates that polar cyanobacteria genomes are underrepresented in reference databases and there is continued need for genome sequencing of polar cyanobacteria. Analyses of the four novel and six existing polar cyanobacteria MAGs and genomes demonstrate they have genes coding for various cold tolerance mechanisms and most standard circadian rhythm genes with the Leptolyngbya sp. BulkMat.35 and Leptolyngbyaceae cyanobacterium MP9P1.79 contained kaiB3, a divergent homolog of kaiB. [ABSTRACT FROM AUTHOR]

The widespread perception of New Zealand is of a group of remote islands dominated by reptiles and birds, with no native mammals except a few bats. In fact, the islands themselves are only part of a wider New Zealand Region which includes a large section of Antarctica. In total, the New Zealand Region has at least 63 recognised taxa (species, subspecies and distinguishable clades) of living native mammals, only six of which are bats. The rest comprise a large and vigorous assemblage of 57 native marine mammals (9 pinnipeds and 48 cetaceans), protected from human knowledge until only a few centuries ago by their extreme isolation in the southwestern Pacific Ocean. Even after humans first began to colonise the New Zealand archipelago in about 1280 AD, most of the native marine mammals remained unfamiliar because they are seldom seen from the shore. This paper describes the huge contrast between the history and biogeography of the tiny fauna of New Zealand's native land mammals versus the richly diverse and little-known assemblage of marine mammals. [ABSTRACT FROM AUTHOR]

As the climate warms, the grounded ice sheet and floating ice shelves surrounding Antarctica are melting and releasing additional freshwater into the Southern Ocean. Nonetheless, almost all existing coupled climate models have fixed ice sheets and lack the physics required to represent the dominant sources of Antarctic melt. These missing ice dynamics represent a key uncertainty that is typically unaccounted for in current global climate change projections. Previous modelling studies that have imposed additional Antarctic meltwater have demonstrated regional impacts on Southern Ocean stratification, circulation, and sea ice, as well as remote changes in atmospheric circulation, tropical precipitation, and global temperature. However, these previous studies have used widely varying rates of freshwater forcing, have been conducted using different climate models and configurations, and have reached differing conclusions on the magnitude of meltwater–climate feedbacks. The Southern Ocean Freshwater Input from Antarctica (SOFIA) initiative brings together a team of scientists to quantify the climate system response to Antarctic meltwater input along with key aspects of the uncertainty. In this paper, we summarize the state of knowledge on meltwater discharge from the Antarctic ice sheet and ice shelves to the Southern Ocean and explain the scientific objectives of our initiative. We propose a series of coupled and ocean–sea ice model experiments, including idealized meltwater experiments, historical experiments with observationally consistent meltwater input, and future scenarios driven by meltwater inputs derived from stand-alone ice sheet models. Through coordinating a multi-model ensemble of simulations using a common experimental design, open data archiving, and facilitating scientific collaboration, SOFIA aims to move the community toward better constraining our understanding of the climate system response to Antarctic melt. [ABSTRACT FROM AUTHOR]