Abstract. Accurate quantification of surface mass balance (SMB) in the Antarctic interior underpins ice sheet mass budget assessments and ice core interpretation. Stake measurements, however, systematically underestimate SMB because firn densification causes surface lowering unrelated to mass change. Here, we simulate firn compaction with a firn densification model and correct stake records from 2008-2024 at Dome Argus (Dome A), East Antarctica, thereby refining SMB estimates and their spatial variability. The mean annual corrected SMB is 24.14 kg m-2 yr-1, 8.8 % higher than the uncorrected value (22.19 kg m-2 yr-1). Over the stake array, the RACMO2.4p1 regional model yields lower and more spatially uniform SMB (17.50 kg m-2 yr-1). Using automatic weather station observations, we estimate annual sublimation of 2.34 mm w.e yr-1. and hoar deposition of 0.87 mm w.e. yr-1, indicating that the net vapor flux is equivalent to 5.7 % of the total mass input. This framework reduces densification induced bias in stake-derived SMB, provides an observational benchmark for evaluating regional climate models, and supports accurate dating of ice core climate records from Dome A.

Antarctic inland regions, as critical hubs for global climate change monitoring, suffer from a lack of reliable long-term greenhouse gas (GHG) observation systems due to extremely low temperatures, strong winds, and limited logistical/energy support. To address this gap, the CRUX-1.0 automatic observation system was developed and deployed at Taishan Station (inland Antarctic Plateau) during the 39th and 40th CHINARE (Chinese National Antarctic Research Expedition), targeting simultaneous monitoring of CO2 and surface ozone (O3). Integrating four core subsystems – analysis, calibration, temperature control, and data communication – the system is specifically engineered for harsh polar environments with low power consumption (<350 W) and autonomous operation capability. The operational analysis based on a 1-month continuous field experiment showed its stable performance: CO2 measurements achieved a coefficient of variation (CV) <5.6 % (nearing 0 % post-calibration), while O3 measurements maintained a CV <5.6 %. The average mixing ratios (CO2: 420.7 ± 0.7 ppm; O3: 20.1 ± 0.8 ppb) closely aligned with regional background levels and South Pole Station data, confirming high reliability. As an unattended system with synchronous CO2/O3 measurement, low-power temperature control and automatic calibration, CRUX-1.0 shows good potential for long-term deployment in data-scarce polar inland regions.

Abstract. Improving the spatial and temporal coverage of volcanic records is essential to accurately quantify volcanic forcing and to provide reliable references for climate models validation. In this study, we present a new volcanic record derived from a 133 m ice core (DA2009) drilled at Dome A, Antarctica. Based on measurements of non-sea-salt sulfate concentrations, 95 volcanic events are identified. Using 15 volcanic age markers aligned with the West Antarctic Ice Sheet (WAIS) Divide ice core (WDC) record, the DA2009 core is dated to cover the past 3951 years, from 1951 BCE to 2000 CE. By comparing the DA2009 record with three Antarctic ice cores from WAIS Divide, Dome C and South Pole, 12 prominent volcanic events are recognized. The period between 1000 and 2000 CE exhibits the most intense volcanic activity of the past 4000 years. The mean snow accumulation rates calculated between adjacent age markers indicate a marked decline in accumulation at Dome A since the 13th century CE. This low-accumulation interval coincides with a pronounced cold phase on the East Antarctic Plateau, suggesting a potential connection between regional climate variability and local accumulation rates at Dome A.

Black carbon (BC) aerosols are considered key factors that contribute to rapid climate warming and ice melt in the Arctic region. However, compared with long-term observations from land-based stations, observational data over the Arctic Ocean remain relatively scarce. Four Arctic scientific expeditions were conducted in the summer and early autumn of 2010, 2012, 2016, and 2018 via the Chinese research vessel Xue Long, during which the BC concentrations along the routes were measured via light absorption methods. In this work, the spatiotemporal distribution characteristics of BC over the Arctic Ocean were examined on the basis of these observations. The potential sources of BC along the various routes were analyzed via the weighted potential source contribution function and weighted concentration-weighted trajectory methods of the hybrid single-particle Lagrangian integrated trajectory model in conjunction with Arctic transport potential climate model simulations. The analysis results indicated that wildfires in the western Aleutian Islands, Siberia, and Far East regions were the primary contributors to the BC aerosol concentration observed along the Arctic expedition routes in summer, identifying these regions as major potential source areas.

Abstract Although mercury (Hg) is a neurotoxic metal of global relevance, its Antarctic biogeochemical cycles are not well characterized. Here, we present the total Hg (THg) distribution and stable isotopic fractionation between the Zhongshan Station and Dome A (1,248 km), in eastern Antarctica, to characterize THg sources and controlling factors. Surface snow samples and snow blocks similarly exhibited higher THg concentrations in the coastal and interior sections than the intermediate section. From the THg distribution and stable isotopic fractionation (notably for 200Hg and 202Hg), we inferred an adjacent oceanic Hg source for the coastal section and primary oceanic sources at 63°S–55°S and 50°S–45°S for the intermediate and interior sections, respectively. Snow drifting and postdepositional effects also influenced THg concentrations and stable isotopic fractionation, particularly in areas with marked terrain slope variations. Finally, the stratospheric contribution of THg near Dome A was negligible, with a possible transport pathway through the lower troposphere.

Regarding the rapid shrinkage of the Arctic cryosphere, sea ice plays a significant role in the temporal storage, transport, and release of microplastics (an emergent pollutant) among atmospheric, aquatic, and terrestrial environments. However, there are sparse studies on microplastics in the landfast sea ice and lagoon lake ice in the Alaskan Arctic region. Therefore, this study investigated characteristics and potential sources of microplastics in the landfast sea ice and lagoon lake ice in the Alaskan Arctic (Point Barrow). The results found that the average abundance of microplastics in the landfast sea ice (220.6±140.1 items/L) was comparable to that in lagoon lake ice near Point Barrow (148.9±141.8 items/L). For different layers of sea ice cores, the maximum abundance of microplastics generally occurred in the bottom layer. The overall particle sizes for the detected microplastics revealed that the abundance of microplastics decreased with increasing size for both landfast sea ice and lagoon lake ice samples. Small-sized microplastics (≤50 μm) accounted for more than 80% of the detected microplastics, with the dominant shape being fragments. The predominant polymers in sea ice were polyamide (PA), polyethylene (PE), and polyethylene terephthalate (PET). Meanwhile, PE and rubber dominated the polymers detected in lagoon lake ice. These differences between microplastics in Arctic sea ice and lagoon lake ice further indicated the discrepancies in microplastic transport pathways and deposition. Microplastics in landfast sea ice were mainly affected by seawater transported from the Pacific Ocean into the Chukchi Sea. In contrast, microplastics in lagoon lake ice were mostly influenced by the seawater of the Beaufort Sea and local vehicle emissions (e.g., rubber). This study further highlighted that a large abundance of microplastics was widely distributed in the sea ice of the Alaska Arctic region and may pose potential risks to the local ecosystems.

As potent greenhouse gases with high global warming potentials, fluorinated gases (F-gases) have emerged as significant contributors to global radiative forcing. Owing to minimal anthropogenic influences, Antarctica provides an exceptional natural environment for investigating background atmospheric F-gas concentrations. This study presents the first comprehensive report of temporal variations in 11 F-gas species at the Zhongshan National Atmospheric Background Station (ZOS; 69.4° S, 76.4° E) throughout 2021. This study is the first to provide concentration changes of 11 F-gases at ZOS in Antarctica in 2021. The datasets are publicly available at the National Tibetan Plateau Data Center at https://doi.org/10.11888/Atmos.tpdc.302283 (Tian et al., 2025). The concentrations of most F-gases significantly increased throughout 2021 at ZOS. The concentrations of F-gases in East Antarctica were greater than those in the Antarctic Peninsula and the interior on the basis of data comparisons with three other Antarctic stations. Back trajectory and clustering analyses using the HYSPLIT model revealed that the contributions of different trajectory clusters were nearly identical at each station. Source apportionment analysis via the PMF model identified industrial processes, refrigeration, fire suppression, and electronics as key contributors to F-gas concentrations in the Antarctic atmosphere. While the one-year observation period precludes long-term trend assessment, these high-frequency measurements capture the baseline variability critical for detecting future anomalies. Continuous multiyear monitoring at ZOS is necessary to establish statistically robust growth rates.

The Southern Ocean (SO) is one of the most important sinks of atmospheric CO2. However, it is lacking data from the other waterbodies of Antarctic continent. This study investigated in situ CO2 and CH4 fluxes in different waterbodies, including coastal seawater of the Terra Nova Bay (TNB) polynya, Ross Sea, snow/meltwater Nansen Ice Shelf, and lakes of Inexpressible Island, East Antarctica during summer, 2022-2023. The results indicate that the TNB polynya is a significant atmospheric CO2 sink (- 133.7--8.0 mmol m-2 d) and a weak CH4 source (- 2.5-13.5 mu mol m-2 day- 1). In contrast, lakes are weak sinks of atmospheric CO2 and CH4 because their low biomass mass. However, one exception was observed in the lagoon and ponds of Adelie penguin colony around Seaview Bay, Inexpressible Island, where penguin guano significantly increased carbon emissions. The largest CO2 emission (29.8-114.7 mmol m- 2 day- 1) was observed in ponds, while the largest CH4 emission (29-50.9 mu mol m- 2 day- 1) was observed in the lagoon, potentially affecting regional carbon emissions. Ponds derived from the meltwater of the Nansen Shelf are weak sinks of atmospheric CO2 and CH4, ranged from- 4.9-2.9 mmol m- 2 day- 1 and-1.3 -0.6 mu mol m- 2 day- 1, with averages of-1.6 mmol m-2 day- 1-0.5 mu mol m- 2 day- 1, respectively. Considering the extensive occurrence of meltwater in west Antarctica, it is essential to further strengthen observations of carbon the ice sheet-ocean interface to understand carbon dynamics in the SO.

Sulfate (SO42-) is an essential constituent of aerosols that play an important role in regulating global climate. Over the past decades, polar sea-ice cover changed significantly, potentially influencing the atmospheric budget of SO42-. However, limited research has been conducted to quantify the effects of sea ice on atmospheric SO42- over different times and regions. Here, we report the SO42-/Na+ mass ratios of aerosols and precipitation samples collected in coastal East Antarctica and the Antarctic Peninsula during 2016-2022. The SO42-/Na+ mass ratios at both sites show similar seasonal trends; aerosols display higher ratios than precipitation in summer, with no significant difference in winter, possibly due to precipitation preferentially removing coarse-mode aerosols. The percentage of air mass travelling time over sea ice (P-Time) is positively correlated with SO42-/Na+ mass ratio (or nss-SO42- concentrations) in summer, suggesting the enhanced atmospheric SO42- production over sea ice due to higher dimethyl sulfide (DMS) emissions and/or enhanced oxidation chemistry of DMS. But this relationship becomes negative during winter, suggesting the predominant influence of sea salt aerosols (SSA) from the sea ice surface on atmospheric SO42- levels. In winter, the SO42-/Na+ mass ratio appears to be relatively invariable when the P-Time exceeds similar to 40-60 %, ranging from similar to 0.08 to 0.18. The lower limit of the mass ratio, similar to 0.08, likely representing the influence of sea ice SSA on the mass ratio. Based on this value, it is estimated that approximately half of the atmospheric SO42- in winter originates from sea ice SSA. These findings highlight the importance of sea ice on aerosol budgets and atmospheric chemistry in polar regions.

Accurate observations of surface mass balance are pivotal for assessing the Antarctic Ice Sheet mass balance and its link to climate dynamics. Studying regional changes in surface mass balance is challenging due to limited on-site observations and the susceptibility of measurements from snow pits and ice cores to localized disturbances. Satellite data and short-term localized measurements suggest no significant changes or a possible increase in surface mass balance across the East Antarctic Ice Sheet in recent decades, but these findings lack large-scale validation. Here we use observations from mass balance stakes to show a significant negative surface mass balance trend along the inland transect from Zhongshan Station to the Antarctic Ice Sheet summit (Dome A) during the period 2005–2020. The mean surface mass balance trend for the inland section over the 15-year period is −2.01 ± 0.37 kg m−2 yr–2, indicating a 35.5

Antarctic trace metal records provide important information for grasping the influence of human activities on the environment over the last centuries. The CA2016-75 ice core is located along the East Antarctic Zhongshan Station–Dome A, enhances the record of metals research in the East Antarctic region, and its high-resolution supplies data support for the study of high-frequency climatic drivers and the effect of human activities on the Antarctic environment. A thorough dataset on seven trace metals (Al, Fe, Mn, Cu, Zn, Ba and Pb) in a coastal ice core in eastern Antarctica during the previous 102 years (1915–2016) is presented in this study. Pb has the lowest concentration (9.51 ± 20.95 pg g−1), and Ba has the highest concentration (36.57 ± 51.35 ng g−1). Notable variations are observed between the pre-1968 AD and post-1968 AD phases for Mn, Zn and Ba. The abrupt, remarkable increase in the concentrations coincided with the change of metal smelting production in the southern hemisphere. In addition to this, it may also be related to local Antarctic scientific research activities. Al and Fe, the primary crustal elements, are essentially obtained from soil dust; Cu shows high crustal enrichment factors (EFc, >10), indicating that it is notably affected by anthropogenic activities. Moreover, the anthropogenic activities in the Southern Hemisphere have had an impact on lead deposition in Antarctica. This study not only enriches the trace metal historical record along the Zhongshan Station–Dome A but also provides a high-resolution ice core record, which is very crucial for the reconstruction of trace metal concentration changes in the last 100 years.

The Antarctic Ice Sheet (AIS) has been losing ice mass and contributing to global sea level rise (GSLR). Given its mass that is enough to cause ∼58 m of GSLR, accurate estimation of mass balance trend is critical for AIS mass loss monitoring and sea level rise forecasting. Here, we present an improved approach to reconciled solutions of mass balance in AIS and its regions from multiple contributing solutions using the input-out, altimetric, and gravimetric methods. In comparison to previous methods, such as IMBIE 2018, this approach utilizes an adaptive data aggregation window to handle the heterogeneity of the contributing solutions, including the number of solutions, temporal distributions, uncertainties, and estimation techniques. We improved the regression-based method by using a two-step procedure that establishes ensembled solutions within each method (input-output, altimetry, or gravimetry) and then estimates the method-independent reconciled solutions. For the first time, 16 contributing solutions from 8 Chinese institutions are used to estimate the reconciled mass balance of AIS and its regions from 1996 to 2021. Our results show that AIS has lost a total ice mass of ∼3213±253 Gt during the period, an equivalent of ∼8.9±0.7 mm of GSLR. There is a sustained mass loss acceleration since 2006, from 88.1±3.6 Gt yr−1 during 1996–2005 to 130.7±8.4 Gt yr−1 during 2006–2013 and further to 157.0±9.0 Gt yr−1 during 2014–2021. The mass loss signal in the West Antarctica and Antarctic Peninsula is dominant and clearly presented in the reconciled estimation and contributing solutions, regardless of estimation methods used and fluctuation of surface mass balance. Uncertainty and challenges remain in mass balance estimation in East Antarctica. This reconciled estimation approach can be extended and applied for improved mass balance estimation in the Greenland Ice Sheet and mountain glacier regions.

The stability of the Larsen C Ice Shelf (LIS) has been widely studied due to its surface lowering, calving, and warming. In this study, we combined multisource remote-sensing data, calculated the long-term series of surface elevation above basal channels and basal melt rate, and analyzed the dynamic changes in the LIS before and after calving in 2017. We found that the basal channels were mainly concentrated in the southern LIS, and the basal melt rate was higher in the south. The Weddell Sea warm water mass entered the bottom of the LIS through the sea trough and promoted basal melting. There was an abnormal basal channel where changes in sea ice concentrations caused by wind-driven currents led to abnormal development. We did not observe significant changes in ice thickness, ice velocity and strain rate in the short term before and after the great calving in 2017. However, the basal melt rate was mainly influenced by the sea ice extent in front of the LIS from 2010 to 2020. Changes in the sea ice extent indirectly altered the proportion of High Salinity Shelf Water (HSSW) entering the ice shelf bottom water mass, which in turn promoted (or inhibited) basal melting of the LIS. In other words, we found no evidence for any dynamic changes in the LIS before and after the great calving in 2017. Since the calving area was within the Passive Shelf Ice (PSI), we have also provided additional evidence for the existence of the PSI. In addition, we speculate that the impact of calving on the LIS will not be visible in the short term, so we need to continuously observe the subsequent dynamic changes in the LIS.

Antarctica is a sink for mercury (Hg) and plays an important role in the global Hg cycle. Knowledge about the environmental fate of Hg in Antarctic terrestrial ecosystems, however, remains highly restricted. In this study, we investigated soil Hg in samples from three areas located across a wide latitudinal range from about 62 degrees S to over 74 degrees S with very different climatic and environmental conditions and different potential (natural and anthropogenic) sources of Hg. The highest Hg levels were found in soils beneath mosses and ornithogenic soils in the Antarctic Peninsula, whereas extremely low values were found in coastal East Antarctica. Total Hg concentrations in soil samples from the three study areas were always closely related to those of organic carbon (OC). In corroborating the results of previous studies, this large-scale survey strongly suggests that OC is a dominant driver affecting Hg distribution in Antarctic soils. The observed linear relationship between Hg and OC concentrations, also supported by available literature data, probably, has a general relevance for Antarctic soils, and allows to identify samples affected by enhanced Hg deposition from anthropogenic or natural sources. In providing a better understanding of the biogeochemical cycle of Hg in Antarctic terrestrial ecosystems, this study suggests that soil OC content must be considered to assess Hg distribution patterns in Antarctic soils. In samples (including those of lacustrine sediments, planktonic, and benthic algal mats) unaffected by an accentuated deposition of Hg, the value of the ratio [Hg ng/g]/[OC %] appears to be less than similar to 11.

Particulate-bound mercury (PBM) measurements in the boundary layer were performed during the 2015-2016 Chinese Antarctic Research Expedition from the middle Northern Hemisphere (Shanghai, China) to the Antarctic Ice Sheet summit, Dome A. A significant latitudinal gradient in PBM was observed. PBM over the Northern Hemisphere oceans was influenced by both continental and oceanic sources, with elevated PBM levels associated with continental inputs. PBM over this region was significantly higher in November than that in April, which could be related to the continental Hg carried by the strong East Asian winter monsoon. Far away from the continental sources, extremely low PBM was observed over the Southern Ocean (2.6 +/- 1.6 pg m-3). Elevated PBM was found across the Antarctic Ice Sheet (79.1 +/- 43.4 pg m-3), and the highest PBM observed at Dome A (143.4 +/- 27.0 pg m-3) was likely associated with GEM emissions from snow and enhanced oxidation of GEM due to snow photochemistry. Across the Antarctic Ice Sheet, PBM increased significantly with the increasing distance from the coast, which may have resulted from the mixing of air masses from the Antarctic plateau and the ocean. GEM emissions from inland Antarctic snow can influence atmospheric PBM concentrations over the Antarctic coastal seas via the transport by katabatic winds, and thus play an important role in atmospheric Hg cycle in the high southern latitudes.

AbstractVery few studies have emphasized the effects of high-pressure sintering on snow density evolution, even though snow as a type of engineering material is widely used in construction engineering in cold regions for snow pavement, snow runway and polar infrastructure. This study presents new experimental results of snow densification under high pressures of up to 100 MPa for a temperature range from −3.5 to −17.3°C and uniaxial compression at the temperature of −10°C and constant strain rates from 5 × 10−4 to 10−1 s−1. Results reveal that density evolution of snow to ice under high-pressure sintering can be achieved in a wide temperature range within a duration as short as 5 min. The compressive strength of snow-sintered ice was ~1.2–2.2 times as large as that of water-frozen ice reported by previous work. The orthogonal experiment showed that pressure is a more significant factor affecting the final density in comparison with sintering temperature and time. The increased rates of ice fabrication, low limitations on temperature and reliable sintered snow strength indicate that snow-ice engineering, such as airport construction in Greenland and Antarctica, can be improved by high-pressure sintering of snow to overcome the harsh environment.

Atmospheric samples and snowfall collected in coastal East Antarctica over two years are used to investigate the sources, production of atmospheric nitrate (NO3-) and its link with snowfall NO3- based upon the isotopic composition of NO3- (delta N-15, delta O-18 and Delta O-17). Snowfall and the atmosphere show similar seasonal trends in concentrations and isotopic composition of NO3-. In summer, atmospheric NO3- is closely associated with snowpack emissions of NOx from photolysis of snow NO3-. In winter, linear relationships between delta N-15 and delta O-18 (or Delta O-17) of NO3- in both snowfall and the atmosphere indicate mixing between stratospheric inputs and tropospheric sources contributing to NO3-, with stratospheric inputs contributing 55 +/- 21% of the atmospheric NO3- budget. The linear relationships suggest that the lower limits of delta N-15, delta O-18 and Delta O-17 of stratospheric-sourced NO3- are close to similar to 18, similar to 120, and similar to 45 parts per thousand, respectively. Concentration correlates well with the isotopic composition of NO3- in winter, indicating less variable contribution of tropospheric sources. A significant linear correlation between delta O-18 and Delta O-17 of NO3- suggests a mix of oxidation processes by O-3 and H2O/OH which can influence NOx cycling and the production of NO3-. Lower values of Delta O-17 of atmospheric NO3- were observed during O-3 depletion events in September, suggesting that oxygen isotopes of NO3- could be more sensitive to the changes in surface O-3 compared to BrO concentrations. Oxygen isotopic composition of NO3- in snowfall is close to that of the atmosphere throughout the year, suggesting that snowfall NO3- can relay information on oxidative chemistry of NOx in the atmosphere. Snowfall delta N-15 is close in value to that in the atmosphere during winter, but similar to 20 parts per thousand higher than that in the atmosphere during summer, possibly associated with seasonal changes in the gas-aerosol partitioning of atmospheric NO3-. This suggests that the interpretation of delta N-15 in snow needs to consider seasonal changes in sources and chemistry. (C) 2021 Elsevier B.V. All rights reserved.