Abstract Improving the accuracy of Arctic seafloor topographic model is of great significance for the research of Arctic shipping lanes, and the IBCAO V4.2 model occupies an important position in Arctic related research fields with its fusion of multi-source sonar data, and the construction of seafloor topographic model by combining bathymetry data and gravity data has obvious advantages in relying on the construction of the model by relying on the bathymetry data, and the Gravity- Geologic Method (GGM) has a significant advantage in this regard. Geologic Method (GGM) can effectively combine bathymetric and gravity data to construct seafloor topographic models. Aiming at the deformation problem of geographic grid and the key parameter density difference in the construction of seafloor topographic model in the Arctic sea by GGM, this paper proposes a way and method to solve the density difference constant by regression analysis under the polar spherical projection condition, and then invert the seafloor topography by GGM. The method takes the eastern part of the Greenland Sea as the test area, and combines the SDUST_GA_2022 satellite data and part of the shipborne measured bathymetry data to construct a seafloor topographic model covering about 7.6×104km2, which is called the AO1-GGM model. The model was externally validated using shipboard measured bathymetry data, and compared with the IBCAO V4.2 model and the AO1-GGM model constructed by relying only on shipboard measured bathymetry data. The results of the study show that 1) in the region where shipboard measured bathymetry data are lacking, the AO1-GGM model can draw topographic details with the help of ocean gravity anomalies in the polar region, and its performance is better than that of the AO1-Grid model. 2) Compared with the IBCAO V4.2 model, the AO1-GGM is more compatible with the actual situation, and it has better results in the checking of the assessment indexes, such as the MSE, RMSE, etc., with an improvement of the accuracy of about 35.01%, and the degree of dispersion of the checking error is smaller. The above results also show that the accuracy of the Arctic seafloor topography model can be significantly improved by integrating multi-source sonar and satellite altimetry and gravity data.

Although the Zoarcidae family is one of the families with the largest number of fish species in the Southern Ocean, there is currently a lack of research on this family. This study analyzed Zoarcidae samples collected from the waters near South Shetland Island during China’s 38th Antarctic Expedition. A combination of morphological examination and molecular methods were used to identify the species of the obtained samples, and the morphological characteristics of the sagittal otoliths were compared through Fourier analysis. The results showed that: (1) fish captured in the waters surrounding the Antarctic Peninsula belonged to four species from four genera, namely Ophthalmolycus amberensis, Pachycara brachycephalum, Lycenchelys nigripalatum, and Lycodichthys antarcticus. (2) The shape of the sagittal otolith in the Zoarcidae fish was mainly elliptical, with a narrow and elongated auditory sulcus extending from the anterior main sulcus to the posterior end of the otolith core. Interspecific differences were mainly reflected in the length of the main sulcus, basal lobe, and pterygoid lobe. The body length was positively correlated with the weight of the otoliths. (3) There were relatively small differences between O. amberensis and L. antarcticus. The greatest differences were between L. nigripalatum and the other three species, which was consistent with the phylogenetic tree results.

The melting of Arctic summer sea ice is accelerating, and studies have shown that the ice melting pool significantly contributes to the positive feedback effect of sea ice melting. However, there is relatively little research on the ice melting layer and its impact on sea ice melting. This study used a low-temperature laboratory to simulate the temperature in the polar region, and conducted experimental research on the effect of different thicknesses of ice meltwater layers under 20 cm and 40 cm of ice on the melting of overlying artificially frozen 20-cm-thick saline water at an ambient temperature of 10 ℃ The heat flux at the ice water interface was also analyzed. The results indicated that: (1) the depth of the freshwater layer was positively associated with the speed at which the saltwater ice melted. Under laboratory conditions, the average melting rate of the freshwater layer was 0.115 cm·h^–1 at a depth of 20 cm and 0.140 cm·h^–1 at a depth of 40 cm, resulting in a difference of approximately 17.86%. (2) The overall average water temperature of the freshwater layer at a depth of 40 cm varied more uniformly over time compared with that of the freshwater layer at a depth of 20 cm. (3) The latent heat flux of the freshwater layer was 92.4 J·(s·m²)^–1 at a depth of 20 cm and 112.4 J·(s·m²)^–1 at a depth of 40 cm, resulting in a difference of approximately 17.8%. The melting process was mainly affected by the latent heat flux. The study findings indicated that the depth of the ice melting layer had a certain impact on the melting of overlying sea ice. This information will provide support for further research on the evolution of Arctic sea ice melting pools.

Although the Antarctic marginal sea is considered one of the cleanest oceans in the world, this region still faces the threat of increasing oil pollution. Researchers have conducted more investigations into oil pollution in the marine sediments of areas such as the Ross Sea and Prydz Bay than in the Cosmonauts Sea and the Amundsen Sea. This study analyzed seafloor surface sediment samples collected in the Cosmonauts Sea and the Amundsen Sea during the 39th Chinese Antarctic Expedition from November 2022 to May 2023. The total petroleum hydrocarbons and polycyclic aromatic hydrocarbons were analyzed by gas chromatography-mass spectrometry, and the oil pollution was evaluated using characteristic indicators. The total petroleum hydrocarbon concentration in seafloor surface sediments was 26.92~44.52 μg·kg^–1 in the Cosmonauts Sea and 5.32~36.19 μg·kg^–1 in the Amundsen Sea; while the polycyclic aromatic hydrocarbon content was 5.22~13.03 ng·g^–1 in the Cosmonauts Sea and 2.67~16.50 ng·g^–1 in the Amundsen Sea. Although the pollutant content was very low, the analysis of oil pollution characteristic indicators showed that the sediments in both seas were affected by oil pollution. This study not only verified the threat of oil pollution to the Antarctic marginal sea, but also provides background data for further in-depth research on total petroleum hydrocarbons and polycyclic aromatic hydrocarbons in surface sediments in relevant sea areas.

Polar ice sheets hold the largest freshwater reserves and profoundly impact global climate change and sea level rise. Ice sheet models are important technical tools for modeling and predicting ice sheet movement. The basal friction distribution is a key boundary condition for solving the ice flow dynamics equations, which is crucial for modeling ice sheet dynamics and predicting future changes. Numerical inversion technology has been widely used in the study of polar ice sheet dynamics to estimate basal friction coefficients in ice sheet models. However, there has not yet been a dedicated review on basal friction inversion methods for polar ice sheets. This paper first reviews recent advances in basal friction inversion of polar ice sheets, and summarizes the commonly used basal friction inversion methods. On this basis, it points out the problems of overfitting and solution instability in the inversion process. Introducing explicit regularization is an effective way to solve the above problems, but the key lies in how to select a reasonable regularization parameter. Then, the latest method for determining the optimal regularization parameter of inversion is introduced in detail, which is based on automatically identifying the inflection point of the L-curve. This method helps to obtain an accurate and reasonable basal friction distribution. Finally, the uncertainty of the basal friction inversion problem is analyzed, and the advantages and limitations of determining the optimal regularization parameter through L-curve analysis in solving the inversion overfitting problem and improving the solution stability are discussed. This paper is expected to provide methodological support for accurately modeling the basal environment of ice sheets and further understanding the connection and interaction mechanisms between subglacial conditions and ice sheet dynamics.

The extreme environments of the polar regions, such as high latitudes, low temperatures, sea ice coverage, and variable climates, have greatly constrained scientific observations in the field. Therefore, the development and use of autonomous underwater vehicle (AUV) have become an essential tool for enhancing the detection capabilities of polar scientific research. This study focused on the current development status, key technologies, and development trends of polar AUV to highlight the progress of AUV applications in the polar region, compares the current status of domestic and international research on polar AUV, and explores typical application scenarios of AUV in the polar region and their main challenges during deployment. This study analyzed the overall design and optimization, cryogenic protection and energy supply, high-precision navigation under ice, and polar deployment and recovery of AUV. Finally, this study summarized the future technological development direction of AUV, which is expected to promote scientific exploration and resource exploration under ice in the polar region, is outlooked. The above results will provide a reference for the future development of future polar equipment.

Owing to the influence of intense snow and the magnetic field in Antarctica, the images collected during field object image monitoring at the Antarctic Research Station have natural or internal noise that seriously affects the image quality and thus affects the monitoring results. Therefore, this study proposed a progressive multi-stage image denoising algorithm based on attention and feature fusion to improve the clarity and realism of the image, eliminate the remaining noise and preserve the details and structure of the image, and reduce the computational complexity of high-resolution feature maps. The algorithm was verified using the object body dataset of monitoring images taken in Antarctica. The experimental results showed that the peak signal-to-noise ratio and structure similarity index measure of the monitored images were 41.82 dB, 38.04 dB, 37.08 dB and 0.991, 0.952, 0.938, respectively, in the presence of salt and pepper noise, periodic noise, and Gaussian noise with standard deviation of 70. The algorithm performed better than mainstream denoising methods and had lower model complexity and stronger noise suppression ability and anti-interference ability. Therefore, the algorithm provides a more reliable technical means for managing the unmanned image monitoring technology in the Antarctic research station.

As changes in polar ice and oceans play an important role in global climate change, polar ice-ocean interactions are becoming an increasingly important part of global climate research. In oceanography research, the basic environmental parameters that describe the most fundamental properties of each ocean and are important analytical indicators for other basic oceanographic studies are temperature, salinity, ocean currents, and sea ice growth and melting. In response to the observation requirements surrounding key environmental parameters of the ice-ocean environment, this study evaluated a newly designed ice-resistant type of ice-ocean dual-purpose autonomous drifting buoy. The buoy had a cylindrical body, an inner core made of ethylene-vinyl acetate copolymer, and a 3-mm-thick RX-802 unsaturated polyester resin coating added to the surface. The cabin was made of 6061-T6 aviation aluminum alloy and was galvanized with cathodic protection to ensure the safety of the control system. The stability and ice resistance of the buoy were calculated by numerical analysis methods, and the wind resistance, ocean current impact resistance, and ice resistance simulation experiments were carried out on the buoy through ANSYS. The experimental results showed that the buoy had good structural characteristics. The dual-master-control redundancy design strategy was adopted to prevent sensor short circuits from causing overall system failure, and the software followed a low-power power management strategy to meet the task requirements of long-term monitoring of the buoy. The buoy completed on-site experiments during China’s 39th Antarctic Research Expedition and successfully obtained data on shallow seawater temperature, chlorophyll concentration, and turbidity to support China’s ice-sea environmental research.

As an effective supplement to “Flag State Control”, “Port State Control (PSC)” has played an essential role in reducing and eliminating non-standard, unsuitable, and high-risk ships. Antarctic gateway countries, such as Australia and New Zealand, play a crucial role in supporting the flows of personnel and materials to and from Antarctica. These Antarctic gateway countries that implement PSC in the Southern Ocean belong to different PSC regional agreements. China has received two notifications of PSC inspections from Antarctic gateway countries since 1984 when China began the Chinese National Antarctic Research Expedition, and Antarctic gateway countries are bound to increase their enforcement of PSC in the future. Therefore, this article systematically reviewed the implementation of PSC in Antarctic gateway countries, analyzed the development trends of PSC in the Southern Ocean waters, explored the potential impact of the PSC inspections in Antarctic gateway countries on China’s Antarctic research vessels, and proposed corresponding strategies for China’s research vessels to respond to the PSC inspections in the Southern Ocean in the future.

Norway, as a key Arctic nation, has accumulated rich experience in participating in Arctic governance processes. However, the evolving geopolitical landscape of the Arctic has shaped Norway’s dual role as both a balancer and a challenger in regional governance. On one hand, as a balancer, Norway has promoted the “limited restoration” of the Arctic Council, and dedicated itself to linking Arctic governance agendas with global governance agendas, striving to secure space for low-political-issue cooperation in the Arctic. On the other hand, as a challenger, it has deepened its strategic alignment with NATO in the Arctic, advanced deep-sea mining proposals, and strengthened its administrative control over Svalbard, sparking international controversy. The tension between these two roles jointly shapes Norway’s Arctic image and the orientation of its future Arctic policies. China-Norway cooperation in the Arctic is deeply rooted, and exploring Norway’s role in Arctic governance and the orientation of its Arctic policies can provide insights for China’s participation in Arctic affairs.