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Analysis of morphological characteristics on glacial valley evolution in Svalbard, Arctic Wang Zemin, Zhang Quchen, Jin Shuang, Ai Songtao Chinese Journal of Polar Research    2022, 34 (3): 255-264.   DOI: 10.13679/j.jdyj.20210043 Abstract （1481）      PDF（pc） （7555KB）（687）       Knowledge map    Save As typical poly-thermal glaciers, Austre Lovénbreen and Pedersenbreen were land-termilated valley glaciers in Svalbard, Arctic. During the 2009 research expedition of Chinese Arctic Yellow River Station, the glaciological research group measured these glaciers by differential Global Position System (GPS) and ground-penetrating radar (GPR). We combined the field acquired GPS and GPR data with power law model for glacial valleys, and presented the glacier valley parameters of Austre Lovénbreen and Peder-senbreen. We then determined the morphological characteristics of glacial bedrock according to the changes of cross-section parameters; analyzed the effect of bedrock erosion on glacial valley evolution; explored the relationship between glacial valley morphology and ice flow velocity by comparing the flow difference between Austre Lovénbreen and Pedersenbreen. The results indicated that glacial valley evolu-tion of Pedersenbreen was better than Austre Lovénbreen, and these glaciers have V-shaped instead of U-shaped valleys, but the evolution status of the two adjacent glaciers showed obvious differences. Ice flow velocity in Pedersenbreen was higher than that in Austre Lovénbreen. The main process of valley formation was lateral erosion in Pedersenbreen and bottom erosion in Austre Lovénbreen. These differ-ences are mainly caused by differences in the glacial valley topography. Reference | Related Articles | Metrics | Comments（0）

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Characteristics and possible causes of long-term wind field variation at Zhongshan Station in Antarctica Wu Weigang, Zhang Wenqian, Wu Maifeng, Ma Jingkai, Ling Xinfeng Chinese Journal of Polar Research    2022, 34 (3): 278-291.   DOI: 10.13679/j.jdyj.20210064 Abstract （1420）      PDF（pc） （6387KB）（1132）       Knowledge map    Save Using on-the-ground meteorological measurements and NCEP/NCAR reanalysis data from 1989 to 2020, we examined changes in wind speed and direction at Zhongshan Station in Antarctica and the mechanisms underlying observed changes. Our findings are as follows: (1) There are clear seasonal variations in wind speed at Zhongshan Station. The wind speed is the highest in winter, second highest in autumn, and the lowest in summer. During the day, wind speed reaches its maximum value at 5 am local time, and its minimum value at 3 pm; there is a single maximum and a single minimum per day. Diurnal variations are large in spring and summer, but small in autumn and winter. (2) Wind speed and frequency of katabatic wind and gale days at Zhongshan Station have decreased over the past 31 years. The rate of decrease is the highest in summer. Results from wind vector decomposition show that the rate of decrease of the southerly winds is significantly higher than the rates of decrease of winds in other directions. The trends of the westerly and northerly winds are not significant. The negative trend of the easterly winds is only significant in summer. (3) The decrease of annual mean wind speed at Zhongshan Station is mainly caused by the decrease in moderate gale and gale days. The changes observed at Zhongshan Station are related to changes in the atmospheric circulation. The weakening of the cold polar high to the south of Zhongshan Station and of the extreme low in the north of the southern Indian Ocean result in a decrease in the pressure gradient and reduced wind speeds at Zhongshan Station. Related Articles | Metrics | Comments（0）

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THE TEMPORAL-SPATICAL DISTRIBUTION OF WATER VAPOR TRANSPORT IN THE ARCTIC Wen Shiqiang, Chang Liang Chinese Journal of Polar Research    2022, 34 (3): 265-277.   DOI: 10.13679/j.jdyj.20210045 Abstract （1362）      PDF（pc） （3414KB）（1115）       Knowledge map    Save In the Arctic (60°N–90°N), water vapor transport directly and indirectly affects aspects of the climate system, including the radiation balance and the dynamics of the hydrological cycle. Understanding the distribution and variations of water vapor transport is important for the study of Arctic climate change. Using ERA5, JRA-55, and MERRA-2 reanalysis data from 1980 to 2018, we analyzed the horizontal and vertical distributions and the monthly and seasonal variations of water vapor flux at 70°N. Our results show that the direction of water vapor transport at 70°N is affected by the distribution of land and sea. Water vapor transport is northward in the eastern Arctic, and alternates between southward and northward in the western Arctic. Water vapor transport in the eastern Arctic is higher than that in the western Arctic. The northward water vapor transport is the highest near the 900-hPa level. At 70°N, the average northward water vapor transport is higher than the average southward water vapor transport. As a result, water vapor accumulates in the Arctic region. The northward water vapor transport is more active in the summer and autumn than in the winter and spring. The water vapor flux increases rapidly near the northward water vapor transport channel and in the North Atlantic region in the summer and autumn. Variations in the temporal and horizontal distributions of water vapor intrusion at 70°N indicate that intrusion mainly occurs near the northward water vapor transport channel, and is more strongly affected by specific humidity than by meridional wind. As a result, there were large fluctuations in the annual average number of water vapor intrusions after 2008. We computed the correlation coefficients between the IGRA2 observation dataset and each of the three reanalysis datasets. The correlation coefficient between IGRA2 and MERRA-2 is positive and is larger than the coefficient between IGRA2 and ERA5 and the coefficient between IGRA2 and JRA-55. Accuracy of MERRA-2 is also higher than that of ERA5 and JRA-55. We conclude that MERRA-2 is the most suitable dataset for the study of water vapor transport in the Arctic. Reference | Related Articles | Metrics | Comments（0）

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Analysis of Sweden’s Arctic strategy for the new decade Yue Peng, Chen Huiwen, Gao Xiaoyan Chinese Journal of Polar Research    2022, 34 (3): 340-351.   DOI: 10.13679/j.jdyj.20210049 Abstract （1360）      PDF（pc） （348KB）（1806）       Knowledge map    Save Under Arctic amplification, the melting of Arctic ice has accelerated in recent years. The era of an ice-free Arctic is arriving. The Arctic is becoming increasingly valuable in terms of resources, transportation, and geopolitics, and is intensifying the competition among the great powers. Increasing confrontations between Russia and US and deteriorating relations between China and US are challenging Arctic security. Sweden considers that a stronger cooperation between China and Russia would lead to considerable changes in Arctic geopolitics. In November 2020, Sweden released its new Arctic report—Sweden’s strategy for the Arctic region 2020. It emphasizes international cooperation, military security, climate and environment, polar research, sustainable economic development, and improvement of residents’ living conditions; residents’ security was especially emphasized. Sweden advocates cooperation and takes on the role of mediator in case of disputes. Sweden is actively responding to the challenges in the Arctic, which include increasing risks of military confrontation, frequent disputes over maritime rights, and insufficient infrastructure. Reference | Related Articles | Metrics | Comments（0）

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Processes underlying the formation and temporal and spatial variability of Arctic polynyas: A review Chinese Journal of Polar Research    2022, 34 (3): 380-396.   DOI: 10.13679/j.jdyj.20210044 Abstract （1340）      PDF（pc） （4808KB）（1534）       Knowledge map    Save Arctic climate is undergoing rapid changes. In the Arctic Ocean, polynyas are the areas with the highest level of activity. The formation and maintenance of polynyas, sea ice formation, and subsequent brine rejection can have profound impacts on the hydrological environment, the survival and development of marine life, and the viability of Arctic shipping routes. However, there is insufficient information on the variability of the location, size, and timing of Arctic polynyas and on the factors and mechanisms that drive and maintain polynyas. There are few Chinese reviews that focus on the processes underlying the formation and the temporal and spatial variations of Arctic polynyas. Therefore, in this paper, we provide an overview of existing studies, and outline current research methods and results with regard to formation mechanisms and processes underlying the temporal and spatial variations. We provide a summary of the effects of polynyas on the Arctic region and the thermodynamic and dynamic factors that influence polynya variation. We highlight prospects for future research on the basis of existing studies. Reference | Related Articles | Metrics | Comments（0）

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Comparative analyses of Arctic sea ice monitoring capability of three sea ice concentration products Huang Rui, Wang Changying, Li Jinhua, Sui Yi Chinese Journal of Polar Research    2022, 34 (4): 471-484.   DOI: 10.13679/j.jdyj.20210087 Abstract （1338）      PDF（pc） （7919KB）（735）       Knowledge map    Save In this paper, three sea ice concentration products are compared: i) data from the Scanning Microwave Radiometer carried on the HY-2B satellite combined with NASA’s TEAM algorithm (“the HY2 dataset”), ii) data from the Microwave Radiometer Imager carried on FY-3D satellite combined with the DT-ASI algorithm provided by Ocean University of China (“the OUC dataset”), and iii) the sea ice concentration product provided by the Ice and Snow Center of the United States (“the NSIDC dataset”). Using the BRM sea ice concentration product with higher spatial resolution and the Moderate Resolution Imaging Spectrometer (MODIS) remote sensing images as reference datasets, we report that: At low latitudes (≤70°N), HY2 is most consistent with. In the mid-latitude region (70°N–80°N), OUC was the most consistent with BRM. At high latitudes (80°N–87°N), the NSIDC dataset is most consistent with the BRM dataset. In the Northeast Passage region, the HY2 dataset is most suitable for sea ice monitoring in the Chukchi Sea and Norwegian Sea segments of the Arctic Northeast Passage during navigation window periods.The NSIDC dataset performs better in each section of the Arctic Northeast Passage near the navigable window period, especially for sea ice monitoring in the East Siberian Sea. The OUC dataset is suitable for the sea ice monitoring needs of most sections of the Arctic Northeast Passage. Reference | Related Articles | Metrics | Comments（0）

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Spatiotemporal variations of Arctic multi-year ice from 2000 to 2019 Hu Haihan , Zhang Zhilun, Li Xinqing, Hui Fengming, Zhao Jiechen, Zhuang Qifeng Chinese Journal of Polar Research    2022, 34 (4): 419-431.   DOI: 10.13679/j.jdyj.20210070 Abstract （1327）      PDF（pc） （2285KB）（1285）       Knowledge map    Save Multi-year sea ice is a critical component of the Arctic ecosystem and can act as an indicator of Arctic climate change. For instance, the spatial and temporal variability of multi-year ice in the Arctic region can reveal broader regional climatic trends. Based on sea ice age and thickness data from the U.S. National Snow and Ice Data Center (NSIDC), this paper analyzed the temporal and spatial variation characteristics of multi-year Arctic ice extent and age from 2000 to 2019. Ice thickness and volume dynamics between 2011 to 2019 are also assessed. An attribution analysis of multi-year ice variations was then carried out based on the reanalysis data provided by the European Center for Medium-Term Weather Forecasting (ECMWF). The results showed that the majority of Arctic multi-year ice (65.6%) was mainly distributed in the central part of the Arctic. Compared with 2000, the extent of multi-year ice decreased by 1.61×106 km2 in 2019, and the proportion of sea ice, which persists for at least five years or more, decreased by 21%. The fastest reductions occurred in the Chukchi Sea and Beaufort Sea. From 2011 to 2019, the average thickness of multi-year ice was 2.35±0.18 m. The increase of ice thickness and volume fluctuated greatly from year to year during the icing period, and the decrease rate during the melting period was generally faster than the increase rate during the icing period. Among the correlation analysis of various environmental parameters, the 2-m air temperature and sea surface temperature exhibited the strongest significant negative correlations with multi-year ice variations, with the correlation coefficients are –0.78 and –0.77, respectively. In light of continued global warming and “Arctic amplification”, more attention should be paid to the future variations of Arctic sea ice, especially multi-year ice changes with greater thickness and longer retention, which have a major impact on the Arctic ice mass balance. Reference | Related Articles | Metrics | Comments（0）

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Polar ice core-based climate and environmental research: A review and perspective Liu Ke Hou Shugui Pang Hongxi Shi Guitao Geng Lei Hu Huanting Song Jing Zhang Wangbin Zou Xiang An Chunlei Yu Jinhai Chinese Journal of Polar Research    2022, 34 (4): 530-545.   DOI: 10.13679/j.jdyj.20210091 Abstract （1272）      PDF（pc） （4768KB）（1800）       Knowledge map    Save Ice cores record past changes in precipitation, temperature, volcanic activity, and solar activity, and are therefore good proxies for studying global climate and environmental change. Polar ice cores play are unmatched in their capacity to extend the time scale of high-resolution paleoclimate records hundreds of thousands or even millions of years into the past. In recent years, a series of new research advances have been made in the study of polar ice cores, but there is still a lack of a systematic summary on this topic. In this paper, the latest research progress related to polar ice cores is reviewed. We mainly focus on polar ice cores’ physical properties, stable water isotopes, soluble and insoluble substances, and trapped gases. Finally, possible future directions of polar ice core research that could provide important new insights are discussed. Reference | Related Articles | Metrics | Comments（0）

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The use and regulation of Unmanned Aerial Systems in the Antarctic and China’s role Chen Yitong, Gao Xiao Chinese Journal of Polar Research    2022, 34 (3): 329-339.   DOI: 10.13679/j.jdyj.20210042 Abstract （1259）      PDF（pc） （379KB）（1110）       Knowledge map    Save Unmanned Aerial Systems (UAS) have been used in the Antarctic region to support scientific research, logistics, tourism, news reporting, and other activities. The use of UAS has been expanding and the locations where they are deployed are also increasing. For the Antarctic region, deployment of UAS is cheaper and more flexible than that of piloted aircraft, but may involve safety and environmental risks. The National Antarctic Programs of the United States, New Zealand, Germany, Poland, Spain, Australia, and the United Kingdom have had extensive experience in UAS deployment and regulation. On the basis of this field experience, the governments of these Antarctic Treaty Consultative Parties have been promoting the development of regulations under the Antarctic Treaty System to manage the use of UAS in the Antarctic. As the expansion of the use of UAS and development of international regulations continue, we recommend that China develop strategies that can take into account its domestic and international interests. Our recommendations are as follows: China should (1) improve its UAS management mechanism, establish the airworthiness of its UAS in Antarctica, and encourage the development of related industries domestically; (2) use its experience in UAS deployment and regulation and actively participate or even take the lead in the development of international regulations of UAS use in the Antarctic to promote its influence in Antarctic governance. Reference | Related Articles | Metrics | Comments（0）

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Assessment of solar photovoltaic power potential at Kunlun Station, Antarctica Wang Tao, Shan Shuo, Jin Xinmiao, Yao Xu, Fang Shixiong, Zhang Kanjian Chinese Journal of Polar Research    2022, 34 (3): 292-302.   DOI: 10.13679/j.jdyj.20210058 Abstract （1251）      PDF（pc） （5971KB）（1191）       Knowledge map    Save We assessed the solar photovoltaic power potential at Kunlun Station, Antarctica with the goal of establishing a photovoltaic plant at the station. We analyzed NASA satellite data of the station area from 2001 to 2017 and conducted forecasts of global irradiance. Our results show that the annual irradiance is high. During the year, there are monthly variations in the irradiance distribution, which remains relatively stable during each month. The average daily irradiance and sunshine hours also exhibit similar variations throughout the year. Using artificial neural networks, we conducted forecasts and climate feedback analysis. Results show that the irradiance is positively correlated with temperature, aerosol, and ozone content, while cloud amount and rainfall show negatively correlation with the irradiance in the Antarctic region. Reference | Related Articles | Metrics | Comments（0）

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Review of carbonate system and carbon sinks of seasonal Arctic sea ice-melt pond systems Cao Junqian, Qi Di Chinese Journal of Polar Research    2022, 34 (3): 352-366.   DOI: 10.13679/j.jdyj.20210059 Abstract （1223）      PDF（pc） （527KB）（1037）       Knowledge map    Save The Arctic sea ice-melt pond system is a key component of the Earth system. Melt ponds occur in spring and summer, and accounts for more than 30% of the sea ice surface. Carbonate systems of sea ice and melt ponds are important components of the high-latitude oceanic CO2 budget. However, the carbon cycle and carbonate system in the melt ponds remain largely unknown. Here we review the current research on the carbonate systems and carbon sink of sea ice and melt ponds. Sea ice and melt ponds undergo similar seasonal changes each year. The enhanced primary production and dissolution of calcium carbonate crystals at the beginning of the melting season promote the strong decline of total alkalinity (TA), dissolved inorganic carbon (DIC) and CO2 partial pressure (pCO2) in sea ice and melt water, while the carbonate system of brineis are mainly controlled by infiltration of melt water. As the melting season advances, air-sea CO2 exchange is promoted and pCO2 of melt water gradually increases because of CO2 exchange with the atmosphere; it fluctuates between zero and atmospheric level until the seasonal sea ice has completely melted. Sea ice melt ponds system can absorb approximately 10.4 Tg of carbon in one year. We identify urgent scientific questions and future research directions with respect to the carbonate systems of sea ice and melt pond. Reference | Related Articles | Metrics | Comments（0）

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Preliminary analysis of otolith morphology of Patagonian toothfish (Disso-stichus eleginoides) from the Kerguelen and Crozet Islands, East Antarctic Yang Dan, Fang Qian, Wei Lian, Zhu Guoping Chinese Journal of Polar Research    2022, 34 (3): 303-310.   DOI: 10.13679/j.jdyj.20210062 Abstract （1178）      PDF（pc） （4874KB）（1085）       Knowledge map    Save Otolith shape analysis has been widely used for stock discrimination. To examine population exchange between stocks in the East Antarctic, we computed six otolith shape indices (form factor, roundness, circularity, rectangularity, ellipticity, and aspect ratio) and elliptic Fourier coefficients for Dissostichus eleginoides from the Kerguelen Islands and the Crozet Islands. Prior to analysis, the influence of individual allometric effect on otolith shape was excluded. Principal component analysis was applied to select the components for subsequent discriminant analysis. We combined the shape indices with the elliptic Fourier coefficients and conducted a discriminant analysis, which had a success rate of 80.00% in the classification of our data. The otolith shape of D. eleginoides from the Kerguelen Islands are similar to those from the Crozet Islands; there are slight differences occur in between the outer edges of the otoliths from the two areas. Otolith shape analysis results and tagging and genetic data from previous studies support a preliminary inference of a population exchange between D. eleginoides from the Crozet Islands and those from the Kerguelen Islands. To elucidate the proportion and mechanisms of stock exchange between two areas, multiple approaches, including otolith chemistry and tagging, are needed. Reference | Related Articles | Metrics | Comments（0）

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Progress and Prospects of Chinese Antarctic Medical Research Chengli Xu Chinese Journal of Polar Research    2024, 36 (3): 486-495.   DOI: 10.13679/j.jdyj.20240040 Abstract （1177）      PDF（pc） （383KB）（489）       Knowledge map    Save Antarctica is one of the places with the most extreme climates on Earth. How humans survive and adapt to the extreme environments in Antarctica is the main focus of Antarctic medical research. This review focuses on the progress of Chinese Antarctic medical research, the selection of expeditioners, and the formulation of relevant standards during the recent 20 years. The main achievements are as follows: 1) Under the condition of Antarctic overwintering, expeditioners may experience desynchronization of circadian rhythm, sleep disruptions, immune-neuroendocrine network dysregulation, and increased negative moods; 2) Under the environment of Antarctic inland, expeditioners may occur acute altitude sickness (AMS), decreased cardiovascular and pulmonary function, sleep disorders, and increased negative moods, such as fatigue; 3) Low blood oxygen saturation, increased AMS scores, cardiac conduction block, and increased negative moods are sensitive indicators for identifying hypoxia susceptible pre-selected inland expeditioners; 4) The only national industry standard for polar medicine, “The requirements of pre-departure physical examination for polar expeditioners”(HY/T 236-2018), was formulated, which provides key technical support for the scientific and standardized selection of expeditioners. In the future, we should continue to study the physiological and pathological changes and mechanisms of stress, adaptation, compensation, and injury of Chinese Antarctic expeditioners under extreme environments, providing scientific suggestions for the selection, adaptation, protection, station management, and related policy formulation of expeditioners. Reference | Related Articles | Metrics | Comments（0）

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Variations in circulation and hydrological characteristics of the Canadian Arctic Archipelago: A review Wang Yurong, Xie Tianli, Zhang Yu, Chen Changsheng, Xu Danya, Hu Song Chinese Journal of Polar Research    2022, 34 (3): 367-379.   DOI: 10.13679/j.jdyj.20210047 Abstract （1169）      PDF（pc） （2713KB）（1043）       Knowledge map    Save The Canadian Arctic Archipelago is an important passage for the outflows from the Arctic Ocean into the North Atlantic Ocean. The variations in the hydrological characteristics and circulation of the Canadian Arctic Archipelago have profound impacts on the marine environment and ecosystems downstream and in the North Atlantic Ocean. Sea ice variability in the Canadian Arctic Archipelago plays a key role in the future security and navigation of the Northwest Passage. The Canadian Arctic Archipelago is a complex region; there is insufficient understanding of the variations in its hydrological characteristics and circulation. In this paper, we review the current research on the volume transport, freshwater transport, heat transport, thermohaline structures, and circulation patterns in the Canadian Arctic Archipelago. We analyze and summarize the main factors and control mechanisms determining the variations; these include sea surface height, wind stress, air pressure, and density distribution. We highlight key issues for future research on the basis of existing studies. Reference | Related Articles | Metrics | Comments（0）

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Comparison and assessment of data on multi-source satellite remote sensing Arctic sea ice thickness Jin Yaqi, Zhang Yu, Chen Changsheng, Xu Danya Chinese Journal of Polar Research    2023, 35 (2): 238-250.   DOI: 10.13679/j.jdyj.20220301 Abstract （1147）      PDF（pc） （13943KB）（705）       Knowledge map    Save Sea ice thickness is one of the important variables of sea ice. Our knowledge of the temporal and spatial integrity of sea ice thickness is still insufficient and lags behind that of sea ice concentration, extent, and drift velocity. At present, Arctic sea ice thickness data are mostly obtained by satellite remote sensing using CryoSat-2 and SMOS, and since November 2018, ICESat-2. Few studies have evaluated the accuracy of the latest multi-source satellite Arctic sea ice thickness data or assessed the spatial and temporal differences of data from different sources. In this study, we quantified the spatial and temporal differences between the latest sea ice thickness data from ICESat-2, CryoSat-2, and CS2SMOS (merged product of CryoSat-2 and SMOS) during 2019–2020. Results show that the mean sea ice thickness is largest in CryoSat-2, second largest in ICESat-2, and smallest in CS2SMOS. There are also considerable temporal and spatial differences. For regions covered with thick sea ice, thickness is largest in ICESat-2, and the thickness in Cryosat-2 is similar to that in CS2SMOS. For marginal ice zones, thickness is largest in CryoSat-2 and smallest in CS2SMOS. The difference between the datasets is smaller over the East Siberian Sea and Beaufort Sea and larger over the Barents Sea. We compared the satellite data with field data collected during Operation IceBridge (OIB) in April 2019 and found that the difference between CS2SMOS and OIB is smaller than that between ICESat-2 and OIB. Reference | Related Articles | Metrics | Comments（0）

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The spatial distribution of icebergs around Antarctica from 2015 to 2020 based on remote sensing Zhang Zhuoyu , Liu Lei , Liu Xuying , Qi Mengzhen Chinese Journal of Polar Research    2022, 34 (4): 432-440.   DOI: 10.13679/j. jdyj.20210078 Abstract （1131）      PDF（pc） （2602KB）（1116）       Knowledge map    Save Icebergs are large pieces of ice produced by the disintegration of ice shelves following crack growth due to the uneven movement speed of each part of ice shelves. The movement and melting of icebergs can transport and subsequently release freshwater to parts of the Southern Ocean that are distant from the Antarctic continent. Accordingly, studying the temporal and spatial distribution of icebergs can provide insights related to the hydrology, ecology, and even the impacts of global climate change across the Southern Ocean. Extracting the iceberg area distribution from remotely sense imagery provides a data basis for such investigations. Using Google Earth Engine, the image dataset of ESA Sentinel-1 SAR images from August 2015 to August 2020 were synthesized. After block resampling, downloading, and splicing, a mosaic map of 400 km around the South Pole within 3 days in winter was obtained; a binary image was then obtained using the grid analysis function, and the area and perimeter of each iceberg was extracted by using data conversion and geometric calculation functions. The results show that many Antarctic icebergs are concentrated within 50 km of the coastline, of which ultra-small icebergs account for nearly 50%. As such, small icebergs may play an important role in the input of fresh water in Antarctica. Reference | Related Articles | Metrics | Comments（0）

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Vessel fleet configuration for liquefied natural gas import via Arctic passage based on the full cost model Shou Jianmin, Zhou Zijing Chinese Journal of Polar Research    2022, 34 (3): 317-328.   DOI: 10.13679/j.jdyj.20210066 Abstract （1131）      PDF（pc） （1353KB）（1095）       Knowledge map    Save The development of energy projects in the Arctic and the decrease of Arctic sea ice extent have opened up new channels for China to import natural gas, which will enhance the security of China’s energy supply. In China, the demand for natural gas is increasing rapidly, and can be met by large-scale import of Arctic liquefied natural gas (LNG). We developed an optimization model to examine the economic and reliability of LNG vessel fleet deployment along the Arctic shipping routes. The model includes a full cost analysis and analyses of navigation conditions of the Arctic passage and the seasonal influence of sea ice conditions on fleet deployment. Using layered modeling and optimization and considering LNG vessels with different loading capacities, we found the optimal fleet configuration for a case study of an annual import of 7 million tons of LNG. The full-cost shipping model established in this paper lays the foundation for economic analyse of Arctic LNG transportation fleets, and provides a tool to support operations of fleets in icy waters. Reference | Related Articles | Metrics | Comments（0）

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Subglacial conditions and processes of the Antarctic ice sheet based on bedrock roughness: A review Li Yanjun , Cui Xiangbin, Qiao Gang, Lang Shinan Chinese Journal of Polar Research    2022, 34 (4): 401-418.   DOI: 10.13679/j.jdyj.20210085 Abstract （1130）      PDF（pc） （9859KB）（816）       Knowledge map    Save Subglacial topography is an important indicator that both reflects and itself influences subglacial conditions and processes of the Antarctic ice sheet. Ice sheet dynamics and basal erosional processes erode pre-glacial topography. As such, bedrock roughness metrics can act as indicators of subglacial conditions and processes (including spatial variability thereof). More specifically, bedrock roughness data can help deduce the material composition of the bedrock, the conditions of sub-glacial erosion and basal sliding, ice dynamics, and subglacial geomorphology. In this study, the potential utility of bedrock roughness characterization and the development of associated quantitative methods are introduced. We focus on the evolution of two methods, one is based on the statistical characteristics of the topography-derived (topographic) roughness and the other is the scattering-derived roughness. Then, relevant studies on subglacial conditions and ice sheet evolution using bedrock roughness were reviewed by evaluating the relationship between bedrock roughness and ice dynamics, subglacial geomorphology, basal thermal mechanism, subglacial geology, and so forth. Finally, the current situation and future potential developments around the study subglacial conditions and processes using bedrock roughness are considered. Reference | Related Articles | Metrics | Comments（0）

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Calibration and preparation of isotopically depleted water standards for spectroscopy Tang Xiaoshuang, Pang Hongxi, Zhang Wangbin Chinese Journal of Polar Research    2022, 34 (3): 311-316.   DOI: 10.13679/j.jdyj.20220007 Abstract （1121）      PDF（pc） （263KB）（851）       Knowledge map    Save Because of very low air temperatures, precipitation and water vapor over continental Antarctica and water vapor near the tropopause are depleted in 18O isotopes. For instance, the ratio of the 18O isotope (δ18O) in water vapor near the tropopause can reach −150‰, which is considerably lower than that in Standard Light Antarctic Precipitation (SLAP; −55.50‰). In mass spectrometry, the calibration of isotopic measurements based on linear interpolation is only valid if the isotopic ratios of the samples fall within the ratio range of reference samples. To meet the needs of high-precision measurements of isotopically depleted water samples, it is necessary to prepare laboratory reference standards that are isotopically depleted. Laser spectroscopy has also been widely used for isotopic measurements of water but the validity of linear interpolation for calibration still needs to be validated by experimental results. We used the principle of mass conservation to determine the δ18O value of 16O-enriched water produced by Sigma-Aldrich ( −940.40‰). We used different mixing ratios of laboratory water standard and 16O-enriched water to prepare four solutions with δ18O values of −76.53‰, −97.08‰, −117.93‰, and −137.50‰, respectively. We measured the isotopic ratios of the solutions using the L2140-i isotope and gas concentration analyzer from Picarro. Results support the validity of calibration based on linear interpolation; mean deviation is only 0.14‰. In this paper, we provided a method for high-precision measurements of stable isotopes in precipitation and water vapor over continental Antarctica and water vapor near the tropopause. Reference | Related Articles | Metrics | Comments（0）

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Spatial distribution of Antarctic krill and their relationship with chlorophyll concentration in the Amundsen Sea in summer Li Shuai, Yang Jialiang, Zhao Guoqing, Li Lingzhi, Rao Xin, Huang Hongliang Chinese Journal of Polar Research    2022, 34 (4): 451-458.   DOI: 10.13679/j.jdyj.20210075 Abstract （1061）      PDF（pc） （599KB）（1161）       Knowledge map    Save Antarctic krill (Euphausia superba) are widely distributed in the Southern Ocean. It is a key species in the Southern Ocean ecosystem and an important food source for whales, fish, penguins and birds, and their density and distribution are strongly affected by environmental factors. Based on acoustic evaluation and survey data from the 36th Chinese Antarctic Research Expedition, One-way ANOVA and bivariate correlation analysis were used to study the spatial distribution characteristics and the relationship with chlorophyll concentration of Antarctic krill in the Amundsen Sea from January 9, 2020 to February 5, 2020. The results showed that the average resource density of Antarctic krill in the Amundsen Sea was 6.36 g·m–2, with the highest proportion (68.18%) falling in the density range of 0~5 g·m–2. Spatial variability in Antarctic krill density was statistically significant (P<0.05). Antarctic krill resources were concentrated in the inshore (72.75°S—76.25°S) and western regions (150°W—158°W) of the Amundsen Sea. The average chlorophyll concentration in the study area was 3.54 mg·m–3, with the highest proportion (38.31%) falling in the 2~3 mg·m–3 concentration range. There was also significant spatial variability in chlorophyll concentrations (P<0.05), which were higher in the coastal waters (72.75°S—76.25°S) and on the eastern and western sides (114°W—119°W and 140°W—158°W) of the Amundsen Sea. A significant positive correlation between chlorophyll concentration and the resource density distribution of Antarctic krill was detected (P<0.05). Reference | Related Articles | Metrics | Comments（0）