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30 March 2018, Volume 30 Issue 1 Previous Issue    Next Issue

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Numerical study of the barotropic tide and tidal energy distribution in the Bering Strait and adjacent sea areas Li Qiang, Gao Guoping, An Baichao, Cheng Linqiao 2018, 30 (1):  1-13.  DOI: 10.13679/j.jdyj.20160056 Abstract ( 737 )   PDF (19819KB) ( 576 )   Based on the Finite-Volume Coastal Ocean Numerical Model(FVCOM), a high-resolution hydrodynamic model was established to study the tides and tidal energetics in the Bering Strait and its adjacent sea areas. The model results were found in good agreement with tide gauge and current data, and the model simulated the hydrodynamics well. Co-tidal charts and the tidal current ellipses of the major constituents were drawn and they were discussed using the calculated results. It was shown that the M2 constituent is dominant in the Bering Sea Shelf, Bering Sea, and Chukchi Sea, whereas the K1 constituent is dominant in Norton Sound. The M2 constituent tidal current velocity is larger in the area of the southeast Bering Sea shelf and Anadyr Bay. The maximum tidal current velocity of the K1 constituent appears in Norton Sound. The model output indicated that the tidal energy flux is small and that the total energy dissipation of the major constituents in the research area is about 751 MW; the M2 tidal energy dissipation accounts for 52% and the K1 tidal energy dissipation accounts for 38%. When the tide enters the Bering Sea shelf, most of the M2 constituent energy is dissipated to the south of St. Lawrence Island, while most of the K1 constituent energy is dissipated in Norton Sound. Related Articles | Metrics

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Effects of Arctic Sea ice on winter temperature in China under climate change Xiao Ying, Ren Yongjian, Du Liangmin 2018, 30 (1):  14-21.  DOI: 10.13679/j.jdyj.20170007 Abstract ( 880 )   PDF (4926KB) ( 1054 )   This study used Chinese winter temperature data, the monthly Arctic sea ice concentration index from the China Meteorological Bureau, and NCEP/NCAR circulation reanalysis data to investigate the effects of Arctic sea ice on winter temperatures in China using sliding, time-delay, and partial correlation analyses. The results showed that Arctic sea ice concentration in autumn was correlated with high pressure in West Siberia in late winter and high pressure in North China, which were responsible for winter temperature anomalies in northwestern China and between the Yangtze River and the Yellow River. Further analysis found that the winter temperature anomalies in the northwestern region were affected mainly by high pressure over West Siberia, while the winter temperature anomalies between the Yangtze River and the Yellow River were affected mainly by high pressure in North China. The influence of Arctic sea ice on the late-winter high-latitude Eurasian circulation further affected winter temperatures on the plateau. Related Articles | Metrics

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Impacts of water mass on the nutrients and phytoplankton community structures in the Norwegian–Greenland Seas During Summer 2012 Gu Fan, Jin Haiyan, Zhuang Yanpei, Zhang Yang, Lu Yong, Wang Bin, Chen Jianfang 2018, 30 (1):  22-31.  DOI: 10.13679/j.jdyj.20170006 Abstract ( 718 )   PDF (7022KB) ( 474 )   During the fifth Chinese National Arctic Research Expedition cruise in summer 2012, the nutrients and phytoplankton pigments in the Norwegian–Greenland seas were analyzed, and the effects of water mass transport on both the distribution of nutrients and the phytoplankton community structures were studied. The results showed that the mean concentrations of nitrate, phosphate, and silicate were 9.0 (±5.0), 0.65 (±0.29), and 1.8 (±1.6) μmol·L−1, respectively, on section AT, and 8.9 (±3.8), 0.71 (±0.22), and 1.8 (±1.6) μmol·L−1, respectively, on section BB. The concentration of silicate in the upper waters of the Norwegian–Greenland seas was considerably lower than that of nitrate because of the limited availability of silicon. With increasing latitude, this limitation diminishes, assuming that the Arctic inflow transports silicon into this area. The distribution of photosynthetic pigments indicated that diatoms were the principal assemblage in the Norwegian–Greenland seas, and that the diatoms were most likely to accumulate above the thermocline below the mixed layer. Prymnesiophyta were found most competitive under low nutrient conditions. In addition, because of the influence of the Atlantic inflow, phytoplankton were found to assemble in Norwegian–Atlantic flow regions where the temperature was higher and the nutrient supply was sufficient; thus, forming the differences observed in the phytoplankton distribution. Related Articles | Metrics

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Effect of double diffusive convection during the evolution of seawater thermohaline structure in Vincennes Bay, Antarctica Zhang Xianliang, Cheng Lingqiao, Gao Guoping 2018, 30 (1):  32-41.  DOI: 10.13679/j.jdyj.20170018 Abstract ( 665 )   PDF (11742KB) ( 462 )   Based on seal CTD data obtained in mid-western areas of Vincennes Bay during March–April 2012, the effect of double diffusive convection during the evolution of the seawater thermohaline structure during the early freezing period was evaluated. Results showed that the effect of double diffusion convection was substantial. The proportion of “diffusion convection” throughout the entire water column was >50%, and strong “diffusion convection” persisted in the deep water from 500 to 800 dbar. The proportion of “salt finger convection” in the water column was ≤10% and it occurred in the mid-layers between 300 and 500 dbar. As the Antarctic winter progresses, brine rejection during sea ice formation makes the water increasingly gravitationally unstable. “Diffusion convection” produces upward fluxes of heat and salinity. The heat flux is in the range of 0.02–0.5 W·m−2, and the average salinity flux is about 10−8 m·s−1. “Salt finger convection” produces downward fluxes of heat and salinity; the average heat flux is about −0.5 W·m−2 and the average salinity flux is about −10−8 m·s−1. During the early freezing period, continuous cooling and brine rejection force the production of dense water with low temperature and high salinity. Double diffusion convection (mainly diffusive convection) reforms the water properties, making the entire water column denser. Therefore, the contribution of double diffusion convection on the formation of dense shelf water in Vincennes Bay is crucial. Related Articles | Metrics

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Analysis of the characteristics of winter gales near the South Georgia Islands in 2016 Liu Wang, Hu Song 2018, 30 (1):  42-49.  DOI: 10.13679/j.jdyj.20160052 Abstract ( 600 )   PDF (9052KB) ( 420 )   The weather at the South Georgia Islands is frequently windy and the general weather situation is complex. Based on surface weather charts and observations from a fishing ship, we concluded that the synoptic situations that lead to winter gales near the South Georgia Islands could be divided into three types: (1) a single cyclone, (2) high pressure to the north and low pressure to the south, and (3) high pressure to the west and low pressure to the east. Type 1 causes gales with moderately short durations. Type 2 causes gales with the longest durations. Type 3 is often generated by an eastward shift of the saddle-shaped pressure system, producing gales with the shortest durations. However, Type 3 can produce wind waves in directions different to the climatological mean direction, which potentially could be dangerous for fishing ships and therefore, careful monitoring is required. Related Articles | Metrics

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Optimal cultivation of Antarctic red yeast and its effect on sea cucumber components Wang Xiaofei, Shi Cuijuan, Kan Guangfeng, Li Liang, Wen Hua, Zhou Ting 2018, 30 (1):  50-56.  DOI: 10.13679/j.jdyj.20160058 Abstract ( 635 )   PDF (1018KB) ( 639 )   Red yeast Rhodotorula is a common type of marine yeast that is often used as a probiotic in aquaculture. Rhodotorula mucilaginosa AN5 was isolated from sea ice during the 22nd Chinese Antarctic expedition, and its fermentation conditions were optimized. The optimal fermentation conditions for AN5 were as follows: 2% molasses, 0.5% yeast powder, 50 mL medium in 250 mL flask, initial pH=3.0, temperature 20°C, and cultivation for 4 days. Under optimized conditions, the number of yeast cells can reach 5.81×107 cells·mL−1. Component analysis of AN5 showed that the contents of water, crude protein, total sugar, and crude fat were 69.15%, 42.00%, 32.08%, and 0.39%, respectively. Juvenile sea cucumbers were fed a diet containing 0.3 g polar yeast per cubic meter water volume. After two months cultivation, in comparison with the control, the juvenile test specimens showed no differences in the contents of water and crude fat but significantly increased contents of protein and total sugar. Consequently, polar red yeast is considered to have potential application as a microecologics in the culture of sea cucumber. Related Articles | Metrics

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Experiments on post-processing of GPS data in airborne geophysical exploration of Antarctica Wang Bangbing, Wang Xuqi, Sun Bo, Yu Linzhe, Guo Jingxue, Cui Xiangbin 2018, 30 (1):  57-66.  DOI: 10.13679/j.jdyj.20160064 Abstract ( 707 )   PDF (1463KB) ( 748 )   It is important to both monitor and predict the behaviors and evolutionary trends of ice sheets in relation to future changes of climate and sea level. Geophysics has particular importance in scientific polar exploration, and the unique advantages provided by airborne geophysical surveys make it an active and promising field of research. China has become the fourth country with a polar airborne geophysical platform, and it has surveyed thousands of square kilometers area of Princess Elizabeth Land, East Antarctica. The objective of this study was to undertake post-processing of GPS data, and to evaluate the accuracy of precise point positioning through comparison experiments. Based on the results of the experiments, we developed software for matching and linking GPS and geophysical data. Then, we summarized a workflow procedure for GPS data processing and we formulated a practical scheme for the post-processing of GPS data acquired during a polar airborne geophysical expedition. The findings of this study can be considered a guiding reference for future related work. Related Articles | Metrics

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Estimation of Antarctic sea ice concentration based on an improved FCLS algorithm Song Xiangyu, Liu Tingting, Wang Zemin, Liu Yanxia 2018, 30 (1):  67-76.  DOI: 10.13679/j.jdyj.20170005 Abstract ( 730 )   PDF (16009KB) ( 491 )   Sea ice has a heat isolation effect that could influence global climate change via modification of the exchange of heat between the ocean and the atmosphere. Sea ice concentration is one of the most important indicators in polar sea ice research. To achieve high spatial resolution in estimations of multitype sea ice concentrations, this study introduced a polarization gradient rate and a spectral gradient rate into a fully constrained least squares (FCLS) algorithm. Accuracy was validated using Antarctic Sea Ice Processes and Climate(ASPeCt) data, and the results were compared with NASA Team2(NT2) and Arctic Radiation and Turbulence Interaction Study Sea Ice(ASI) algorithms. The root mean square error(RMSE) and bias of the improved FCLS algorithm throughout the year were 13.8% and −0.7%, respectively. The accuracy of the improved algorithm was found better for multiyear ice than first-year ice. Related Articles | Metrics

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Research on the representation and the construction of polar scientific data ontology based on spatial relations Huang Dongmei, Zhang Qian, Wang Jian, Wei Quanmiao, Shi Jingcong, Zhu Jiangang 2018, 30 (1):  77-87.  DOI: 10.13679/j.jdyj.20170011 Abstract ( 657 )   PDF (1703KB) ( 601 )   The polar region is currently a focus of worldwide attention and an area of active research. The rapid growth of multidisciplinary polar science data has led to the need for effective management of these data and for the provision of intelligent data services. To overcome problems such as incomplete and/or inaccurate data retrievals in a data sharing platform based on key words and subjects, this paper proposes a polar science data ontology library based on spatial relations. First, the method of construction of polar science data ontology is discussed in terms of spatial relations by studying the semantic concepts, attributes, and relations of polar science data. This is undertaken in conjunction with the formal representation model of spatial relations in ontology construction, based on the metadatabase of the Chinese National Arctic and Antarctic Data Center, and the concept of ontology. Then, a general framework of polar ontology is designed with consideration of spatial relations. Finally, a polar science data ontology library is built using ontology construction tools. Related Articles | Metrics

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Research on current situation of Arctic maritime rights and interests from a mapping perspective Cheng Kunfeng, Pang Xiaoping, Liu Haiyan 2018, 30 (1):  88-96.  DOI: 10.13679/j.jdyj.20160063 Abstract ( 684 )   PDF (504KB) ( 688 )   It is fundamental to the future of Chinese Arctic activities to clarify the Arctic maritime rights and interests of all concerned countries. To elucidate the current situation, this study conducted quantitative and spatial mapping-based analyses of the exclusive economic zones, outer continental shelf platforms, and marine protected areas claimed by the countries surrounding the Arctic. The results were considered in combination with related legal policies both to predict the developing trends of Arctic maritime rights and interests and to explore their influence on China’s future involvement in the Arctic region. The findings of this study could serve as a reference for the strategic planning of future Chinese Arctic activities. The results show that it has a certain regularity on the coastal countries' restriction of the Arctic Ocean activities. It shows a significant zonal distribution meridionally, where the restriction gradually weakened as the latitude increases. In depth , the control range of the continental shelf is greater than that of the superjacent waters. Related Articles | Metrics

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Progress in application of airborne gravity measurements in polar regions Gao Shengjun, Hao Weifeng, Li Fei, Guo Jingxue, Cui Xiangbin 2018, 30 (1):  97-113.  DOI: 10.13679/j.jdyj.20170020 Abstract ( 727 )   PDF (49637KB) ( 470 )   This review introduces the basic principles of airborne gravity measurements, summarizes the history of development of both international and Chinese airborne gravity measurement technology, and describes the application of airborne gravity measurement technology to airborne geophysical exploration in polar regions. It is confirmed that airborne gravity measurement technology is the only means of obtaining such high-precision high-resolution observations of the entire Antarctic area. Thus, the technology is vital to improving the global gravity field model in Antarctica, supporting research of Antarctic geological structures, and enhancing data quality. Related Articles | Metrics

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Review of research on air–sea CO2 flux and its controlling factors in the Bering Sea Sun Heng, Gao Zhongyong 2018, 30 (1):  114-121.  DOI: 10.13679/j.jdyj.20170016 Abstract ( 686 )   PDF (749KB) ( 622 )   The Bering Sea, in the Pacific sector of the Arctic Ocean, represents a typical area of transition from a sub-Arctic ecosystem to an Arctic ecosystem. The study of its CO2 sources and sinks will provide an important reference for high-latitude continental margin regions. Within the context of global warming, the Bering Sea is undergoing climatic and environmental changes. The effects of these changes on both the CO2 sources and sinks and the related biogeochemical processes of the area are considerable. This paper summarizes the CO2 sources and sinks and their control mechanisms in the Bering Sea, describes the tendencies of those CO2 sources and sinks, and predicts their future prospects. Previous studies have argued that the Bering Sea acts as a sink for atmospheric CO2 but the results have been notably varied. Recent studies have reported that the CO2 sinks on the Bering shelf and in the entire Bering Sea are about −6.81×1012g C·a-1 and −34×1012g C·a−1, respectively. However, if climatic and environmental changes continue to intensify in the future, conditions that could result in a decrease or in an increase in the magnitude of the CO2 sink might exist simultaneously. Therefore, it remains inconclusive whether the function of the Bering Sea as a carbon sink will be enhanced or weakened in the future. Related Articles | Metrics