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30 September 2020, Volume 32 Issue 3 Previous Issue    Next Issue

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A preliminary study of intertidal meiofauna in Fildes Peninsula, Antarctica Liu Xiaoshou, Wang Xiaoxiao, Wang Lu, Zhang Zhinan 2020, 32 (3):  281-289.  DOI: 10.13679/j.jdyj.20180016 Abstract ( 826 )   PDF (1099KB) ( 981 )   The polar regions are the only regions on the planet that have not been greatly impacted by human activities. However, there are inadequate studies of zoobenthos in the Antarctic intertidal zones. Therefore, during the 29th Chinese Antarctic Research Expedition between January and February 2013, we assessed taxa composition and distribution patterns of meiofauna, and studied intertidal meiofauna and their relationships with environmental factors at 20 sites in Fildes Peninsula, King George Island in the South Shetland Islands. Our goal was to provide basic information to understand influence of human activities and climate change on polar intertidal meiofauna. Average meiofauna abundance was 256.8 ind.·(10 cm2)–1 and average biomass was 370.5 μg·(10 cm2)–1. A total of 9 meiofaunal taxa were identified, including free-living marine nematodes, copepods, oligochaetes, ostracods, bivalves, gastropods, turbellarians, and halacarids. Marine nematodes were the most abundant, accounting for 82.7% of the total meiofaunal abundance. In terms of biomass, oligochaetes were the most dominant, accounting for 41.7% of the total meiofaunal biomass. Marine nematodes accounted for the second highest percentage of total meiofaunal biomass (22.9%). CLUSTER analysis showed that meiofaunal assemblages were correlated with habitat types. Correlation analysis showed that abundance and biomass of meiofauna and marine nematodes were significantly correlated with sediment organic matter content and phaeophorbide concentration. References | Related Articles | Metrics

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Possible linkages between the 11-year solar cycle and Antarctic sea ice variability Zhou Qun, Chen Wen 2020, 32 (3):  290-300.  DOI: 10.13679/j.jdyj.20190048 Abstract ( 786 )   PDF (949KB) ( 852 )   Using NCEP-DOE reanalysis datasets, sea ice concentration data from the Hadley Center and sunspot number data, we investigated possible linkages between Antarctic sea ice and the 11-year solar cycle as well as related physical processes. In years with high solar activity, sea ice concentration is low in the vicinity of the Ross Sea and high in the Weddell Sea near the Antarctic Peninsula. We introduced a sea ice dipole (SID) index, and found that Antarctic SID is significantly negatively correlated with the Antarctic Oscillation (AAO), possibly through the mediation of the westerly jet. When the AAO is strong, the westerly stream turns southward around the Antarctic Peninsula–Weddell Sea, and northward near the Ross Sea, resulting in negative SID anomalies as warm air enters the Antarctic Peninsula–Weddell Sea region and cold air intrudes over the Ross Sea. Sea ice and circulation anomalies are reversed when the AAO is weak. This indicates that solar activity and Antarctic sea ice variability may be linked through the effects of solar activity on AAO, which may originate from temperature responses in the stratosphere. As a result of changes in meridional circulation, redistribution of air masses in the atmosphere tends to induce negative AAO in the lower troposphere during years with high solar activity. References | Related Articles | Metrics

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Comparison and verification of remote sensing sea ice concentration products for Arctic shipping regions Wang Jian, Qiu Yubao, Xiong Zhenhua,Yuan Xiping, Zhou Jingtian, Huang Lin, Shi Lijuan 2020, 32 (3):  301-313.  DOI: 10.13679/j.jdyj.20190054 Abstract ( 1124 )   PDF (4122KB) ( 1244 )   We analyzed and evaluated sea ice concentration data from the marginal ice zone in eight publicly available Arctic sea ice concentration products. Mean bias and standard deviations were derived from the products and compared. Means bias values indicate that Bremen/Artist Sea Ice, Bremen/BT(Bootstrap), NSIDC(National Snow And Ice Data Center)/BT and NSIDC/CDR(Climate Data Record)/ BT products are higher than the mean of the eight products for the entire year of the study period, and their mean bias are higher in summer than in winter. Annual mean bias of Hamburger/ASI product is lower than the mean of the eight products, negative in winter and spring, and positively increasing in summer. Annual mean bias of NSIDC/NT(NASA Team), NOAA OI SIC and OSISAF products are negative and lower in summer and autumn. Large standard deviations in summer and autumn are mainly found along the Northeast Passage where ice cover is thin (marginal ice zone). There are large variations in standard deviation in the regions of the East Siberian, Laptev and Kara Seas; values increase from 3% in spring to 10%–15% in winter. Correlating the eight products with MODIS images at a resolution of 25 km, we found the lowest correlation coefficient (0.63) in the NOAA OI SIC product (0.25° resolution), while correlation coefficients for the two products from Bremen are highest (both 0.80). Bremen/BT has the lowest mean deviation (7.11%). Products derived using the ASI algorithm have higher mean bias; mean bias of the Bremen/ASI and Hamburger/ASI products are 14.38% and 14.99%, respectively, and deviations fluctuate greatly in summer and autumn. Standard deviation of Bremen/ASI products is 11.01%, and SD of Hamburger/ASI product is 12.16%. Our research results are important for the application of remote sensing data products to support maritime navigation in marginal ice zones, and for future development of sea ice concentration algorithms. References | Related Articles | Metrics

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Remote sensing monitoring of river networks in the Inglefield Land of the northwest Greenland ice sheet Li Ya, Lu Yao, Lu Xin, Li Manchun, Yang Kang 2020, 32 (3):  314-321.  DOI: 10.13679/j.jdyj.20190055 Abstract ( 830 )   PDF (7487KB) ( 482 )   Mass loss of the Greenland ice sheet has accelerated in recent years due to increases in surface meltwater runoff. Each year during the melt season, large and complex supraglacial river networks form on the northwest Greenland ice sheet surface. A large amount of meltwater is transferred to the ice sheet margin, feeds the proglacial river network and finally flows into the ocean. This process is important, because it considerably affects ice sheet mass balance and contributes to global sea rise. However, there have been few studies investigating the proglacial and supraglacial river network of the northwest Greenland ice sheet and the morphological and structural characteristics remain unclear. Here, we extracted the supraglacial and proglacial river network in the Inglefield Land(4 624 km2) from 10 m Sentinel-2 images acquired on July 25, 2018, August 14, 2018 and August 25, 2018 using the criteria of Gaussian-like backscattering cross sections and longitudinal continuity. We monitored the dynamic changes of supraglacial and proglacial river network by supraglacial drainage density and proglacial river width. We found that there are parallel supraglacial drainage patterns and dendritic proglacial drainage patterns on the northwest Greenland ice sheet during the melt season, and supraglacial river networks are gradually expanding toward higher elevation. We found a high level of consistency between proglacial river width and supraglacial drainage density. References | Related Articles | Metrics

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Effects of climate change on Antarctic supraglacial lakes: Case study of the Amery and Larsen A ice shelves Wang Hui, Lu Shanlong, Ding Jun, Qiu Yubao, Tang Hailong, Yan Qiang 2020, 32 (3):  322-335.  DOI: 10.13679/j.jdyj.20190062 Abstract ( 879 )   PDF (3353KB) ( 1115 )   As a sensitive indicator of regional climate change, Antarctic supraglacial lakes are important for studying the stability of the cryosphere under global climate change. Using the Normalized Difference Water Index, we extracted supraglacial lakes on Amery Ice Shelf in East Antarctica and Larsen A Ice Shelf in West Antarctica from Landsat Enhanced Thematic Mapper (ETM +)/ Operational Lander Imager (OLI) images and Landsat Image Mosaic of Antarctica (LIMA) mosaic images, and explored teleconnections between supraglacial lakes and 2000–2019 regional meteorological data, and the relationship between supraglacial lakes and regional climate change. Total surface area of supraglacial lakes on Amery Ice Shelf is relatively stable and decreasing, while that on Larsen A Ice Shelf is increasing. We found positive feedbacks between lake surface area, air temperature and sea surface temperature, which differ between the two ice shelves. On Amery Ice Shelf, lake surface area is con-siderably affected by air temperature, and unaffected by sea surface temperature. On Larsen A Ice Shelf, lake surface area is sensitive to changes in sea surface temperature and varies with sea surface temperature. References | Related Articles | Metrics

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Extracting freeze/melt extent of Greenland ice sheet from Synthetic Aperture Radar images Zhao Mengxue, Fu Wenxue, Sun Yanwu, Li Xinwu 2020, 32 (3):  336-342.  DOI: 10.13679/j.jdyj.20190063 Abstract ( 646 )   PDF (2808KB) ( 658 )   Data on freezing and melting of polar ice sheets are important for understanding ice sheet stability and ice sheet response to climate change. We examined relationships between ice sheet freeze/melt extent, HH and HV polarization amplitudes and HH/HV values using Sentinel-1A IW SAR images from 2016, AWS data and MODIS temperature products. We found that freeze/melt extent is negatively correlated with HH and HV polarization amplitudes and positively correlated with HH/HV value, and R2 is higher in the correlation with HH/HV value (> 0.6) than that with polarization amplitudes. Using MODIS temperature products, we established five HH/HV thresholds to measure freeze/melt extent of the Greenland ice sheet. Using MODIS temperature products, we found that the accuracy of extracting freeze/melt extent using HH/HV value is 86.8%. References | Related Articles | Metrics

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Estimating near-surface atmospheric refractive index structure constants at Antarctic Taishan Station using simulated parameters from Polar WRF Yang Qike, Wu Xiaoqing, Han Yajuan, Qing Chun 2020, 32 (3):  343-351.  DOI: 10.13679/j.jdyj.20190065 Abstract ( 743 )   PDF (4833KB) ( 769 )   Optical turbulence intensity in the near-surface layer is closely related to the quality of potential astronomical observatory sites. Compared with the middle and low latitudes, Antarctica has very low background radiation, aerosol concentration and light pollution, and is an attractive location for the establishment of astronomical observatories. Conventional meteorological parameters at Antarctic Taishan Station were simulated using the Polar Weather Research and Forecasting model (Polar WRF), which has been developed specifically for polar research. Correlation coefficient between simulated and measured temperature was up to 0.95 and that between simulated and measured wind speed was up to 0.89. Refractive index structure constant () was estimated from the simulated meteorological parameters using the Monin–Obukhov similarity theory, and compared with values derived from measurements from the mobile polar atmospheric parameter measurement system at Taishan Station. There is high consistency between simulated and measured values. Correlation coefficient between simulated and measured values is 0.67. References | Related Articles | Metrics

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Special design of the laboratory of polar research icebreaking vessel Xuelong 2 Chen Qingman, Wang Shuoren, Yuan Dongfang 2020, 32 (3):  352-361.  DOI: 10.13679/j.jdyj.20200026 Abstract ( 901 )   PDF (2601KB) ( 1253 )   The polar research icebreaking vessel Xuelong 2 has been designed with research in an addition to transportation in mind. To meet the experimental needs of multiple scientific disciplines, the design concept of modularity and flexibility in a limited laboratory space has been adopted. Laboratory efficiency is enhanced by constructing a large laboratory that can meet the general requirements of all disciplines as much as possible. Flexible design ensures that special needs of different disciplines can be met. Combining the deployment of a mobile container laboratory with a rotating shift schedule greatly increases the number of experiments that can be accommodated. The design concepts of modularity and flexibility are implemented through the use of modular test benches, flexible water and electricity systems, standard fixed equipment and intelligent terminals. A modern icebreaking polar research vessel needs to satisfy the conflicting requirements of research and transportation. Long voyages often provide short windows for data collection. Vessel size limits variety and volume of laboratory space. However, these limitations have been effectively resolved through comprehensive design planning taking into consideration of many disciplines. References | Related Articles | Metrics

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Wind resource assessment for the Northwest Passage Qian Heng, Zhang Ren 2020, 32 (3):  362-372.  DOI: 10.13679/j.jdyj.20190050 Abstract ( 860 )   PDF (5229KB) ( 731 )   The Northwest Passage is a fragile environment. It is also a strategic location for energy development. Therefore, we evaluated offshore wind energy potential over the Northwest Passage to provide information to support decisions for offshore wind energy site selection and development. Using ERA-Interim wind fields data, we analyzed characteristics of wind energy over the Northwest Passage, including wind power density, and wind energy availability, abundance, stability and storage. Results show that wind energy is abundant in the Northwest Passage with the highest wind energy potential located in the eastern Arctic Ocean around Davis Strait, Amundsen Gulf, and areas between Parry Islands and McClintock Strait (such as Victoria Strait). These regions are key area for maritime transport and have high wind energy potential in terms of wind power density, effective wind speed and energy level occurrence probabilities, energy storage and coefficient of variation without notable signs of decline over the long term. References | Related Articles | Metrics

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Analysis on the process of Ross Sea Region MPA establishment under rights and interests claims and its implications Zou Leilei 2020, 32 (3):  373-382.  DOI: 10.13679/j.jdyj.20190046 Abstract ( 864 )   PDF (522KB) ( 916 )   After 5 years of negotiations, the Commission for the Conservation of Antarctic Marine Living Resources reached consensus in October 2016 on the establishment of the Ross Sea Region Marine Protected Area (RSRMPA) in the Antarctic. During the negotiations, some states expressed concerns out of fear and suspicion that control would be enforced in accordance with the boundaries defined by the territorial claims, and that fishery rights would be curtailed. Concerns over states’ claims for rights and interests prolonged the negotiation. Consensus on the establishment of RSRMPA can at least in part be attributed to compromises reached among different states. China is motivated to become a key player in the establishment and management of Antarctic Marine Protected Areas (MPAs) because MPAs may facilitate a new approach to Antarctic marine ecosystem protection. To achieve this goal, China needs to learn from the experience of the RSRMPA negotiations, gain knowledge about states’ rights and interests claims in MPA proposals, enhance negotiation skills, become actively involved in MPA regime making, and promote scientific research to improve the scientific understanding of MPAs. References | Related Articles | Metrics

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A study of China’s deep engagement in Arctic governance: From the perspective of concluding the Agreement to Prevent Unregulated High Seas Fisheries in the Central Arctic Ocean Tang Yao 2020, 32 (3):  383-393.  DOI: 10.13679/j.jdyj.20190061 Abstract ( 841 )   PDF (1371KB) ( 809 )   International rule-making is part of China’s participation in Arctic governance. Agreement to Prevent Unregulated High Seas Fisheries in the Central Arctic Ocean undoubtedly represents a milestone for China as this is the first Arctic regional treaty that China has signed since the end of the Cold War. However, China’s participation also highlighted some problems. A gap remains between China and other treaty parties in terms of willingness and capability to participate. China also failed to make full use of related institutions, regimes and organizations. China participates constructively in the making of international rules in the Arctic, and could become a pioneer with a deep engagement in Arctic governance. Therefore, China should strengthen and improve its willingness and capability to participate, make full use of related institutions, regimes and organizations, and show deep engagement in Arctic governance by concluding the treaty. References | Related Articles | Metrics

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Latest change, driving force and future prospect of Finland's Arctic policy to China Liu Han 2020, 32 (3):  394-401.  DOI: 10.13679/j.jdyj.20190070 Abstract ( 814 )   PDF (320KB) ( 1337 )   With an important strategic location in the Arctic, Finland plays an influential role in international Arctic affairs. Bilateral relations between China and Finland form a solid foundation for Arctic cooperation between the two countries, and their cooperation over Arctic economic development has been further promoted by the publication of China’s Arctic Policy. However, the newly released report China in the Arctic and the Opportunities and Challenges for Chinese–Finnish Arctic Cooperation indicates that Finnish attitude towards cooperation with China over economic development in the Arctic may be wavering. The report expresses skepticism over the reliability of Chinese investors, and highlights the potential risks of Chinese–Finnish Arctic cooperation. The change in Finnish attitude is partly a result of adjustments of Finnish national interests in the Arctic, insufficient momentum in Finnish Arctic infrastructure projects, and skepticism of western countries towards the Polar Silk Road. In face of this challenge, China should maintain confidence in Chinese–Finnish Arctic cooperation, advocate strategic docking, and seize opportunities to deepen bilateral and multilateral cooperation to dispel doubts, build trust, and strengthen positive interactions in different domains between China and Finland. References | Related Articles | Metrics

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Review of sea ice variability in Canadian Arctic Archipelago and associated change factors Shen Xinyi, Zhang Yu, Chen Changsheng, Hu Song 2020, 32 (3):  402-414.  DOI: 10.13679/j.jdyj.20190068 Abstract ( 843 )   PDF (5629KB) ( 965 )   The Canadian Arctic Archipelago is an important gateway for Arctic freshwater outflow. Variability of sea ice and Arctic freshwater flowing through the Canadian Arctic Archipelago has profound impacts on the hydrology, environment and ecosystems of the North Atlantic downstream. Sea ice variability in the Canadian Arctic Archipelago also plays an important role in navigation of the Northwest Passage. However, processes and mechanisms of sea ice change in the Canadian Arctic Archipelago are insufficiently described by existing studies because of temporal and spatial limitations of observational data. This paper reviews current research on sea ice concentration, extent, thickness and flux in the Canadian Arctic Archipelago, analyzes the effect of sea ice variability on navigation of the Northwest Passage, and summarizes the main factors affecting sea ice variability in the Canadian Arctic Archipelago. These include thermodynamics and dynamics of atmospheric circulation and changes in the ocean. We identify prospects for future research on the basis of existing findings. References | Related Articles | Metrics

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The first Arctic ozone hole in 2020 Lu Longhua 2020, 32 (3):  415-416.  Abstract ( 541 )   PDF (801KB) ( 677 )   References | Related Articles | Metrics