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28 September 2022, Volume 34 Issue 3 Previous Issue    Next Issue

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Analysis of morphological characteristics on glacial valley evolution in Svalbard, Arctic Wang Zemin, Zhang Quchen, Jin Shuang, Ai Songtao 2022, 34 (3):  255-264.  DOI: 10.13679/j.jdyj.20210043 Abstract ( 1481 )   PDF (7555KB) ( 687 )   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. References | Related Articles | Metrics

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THE TEMPORAL-SPATICAL DISTRIBUTION OF WATER VAPOR TRANSPORT IN THE ARCTIC Wen Shiqiang, Chang Liang 2022, 34 (3):  265-277.  DOI: 10.13679/j.jdyj.20210045 Abstract ( 1362 )   PDF (3414KB) ( 1114 )   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. References | Related Articles | Metrics

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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 2022, 34 (3):  278-291.  DOI: 10.13679/j.jdyj.20210064 Abstract ( 1420 )   PDF (6387KB) ( 1132 )   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. References | Related Articles | Metrics

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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 2022, 34 (3):  292-302.  DOI: 10.13679/j.jdyj.20210058 Abstract ( 1251 )   PDF (5971KB) ( 1191 )   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. References | Related Articles | Metrics

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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 2022, 34 (3):  303-310.  DOI: 10.13679/j.jdyj.20210062 Abstract ( 1178 )   PDF (4874KB) ( 1085 )   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. References | Related Articles | Metrics

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Calibration and preparation of isotopically depleted water standards for spectroscopy Tang Xiaoshuang, Pang Hongxi, Zhang Wangbin 2022, 34 (3):  311-316.  DOI: 10.13679/j.jdyj.20220007 Abstract ( 1121 )   PDF (263KB) ( 851 )   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. References | Related Articles | Metrics

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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 2022, 34 (3):  317-328.  DOI: 10.13679/j.jdyj.20210066 Abstract ( 1131 )   PDF (1353KB) ( 1095 )   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. References | Related Articles | Metrics

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The use and regulation of Unmanned Aerial Systems in the Antarctic and China’s role Chen Yitong, Gao Xiao 2022, 34 (3):  329-339.  DOI: 10.13679/j.jdyj.20210042 Abstract ( 1259 )   PDF (379KB) ( 1108 )   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. References | Related Articles | Metrics

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Analysis of Sweden’s Arctic strategy for the new decade Yue Peng, Chen Huiwen, Gao Xiaoyan 2022, 34 (3):  340-351.  DOI: 10.13679/j.jdyj.20210049 Abstract ( 1360 )   PDF (348KB) ( 1806 )   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. References | Related Articles | Metrics

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Review of carbonate system and carbon sinks of seasonal Arctic sea ice-melt pond systems Cao Junqian, Qi Di 2022, 34 (3):  352-366.  DOI: 10.13679/j.jdyj.20210059 Abstract ( 1223 )   PDF (527KB) ( 1037 )   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. References | Related Articles | Metrics

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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 2022, 34 (3):  367-379.  DOI: 10.13679/j.jdyj.20210047 Abstract ( 1169 )   PDF (2713KB) ( 1043 )   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. References | Related Articles | Metrics

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Processes underlying the formation and temporal and spatial variability of Arctic polynyas: A review 2022, 34 (3):  380-396.  DOI: 10.13679/j.jdyj.20210044 Abstract ( 1340 )   PDF (4808KB) ( 1534 )   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. References | Related Articles | Metrics

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Polar radioglaciology: Frontiers in technology and methods 2022, 34 (3):  397-400.  Abstract ( 936 )   PDF (229KB) ( 1438 )   Related Articles | Metrics