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30 June 2019, Volume 31 Issue 2 Previous Issue    Next Issue

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A review of the stable isotopic composition of nitrate in Antarctic snow and ice Shi Guitao, Qin Rui, Ma Hongmei, Hu Zhengyi, An Chunlei, Jiang Su, Li Yuansheng 2019, 31 (2):  117-127.  DOI: 10.13679/j.jdyj.20180047 Abstract ( 721 )   PDF (1646KB) ( 996 )   As a major chemical component in Antarctic snow and ice, nitrate (NO– 3) has been widely investigated, as these data can potentially deliver information on the past climate. Unlike other chemical ions (e.g., Na+ and K+), NO– 3 is not irreversibly deposited into snowpacks, as it will undergo post-depositional processing, which will significantly affect the initial atmospheric information and hamper the interpretation of ice-core records. The isotopic composition of NO– 3 can deliver more information than possible with determinations of the concentration alone; that is, the nitrogen and oxygen isotopes can suggest the sources of NOx and the oxidation capability of the atmosphere. Owing to limited amounts in samples, especially ice cores, and the low concentrations of NO– 3 in Antarctic snow and ice, investigations on isotopes of NO– 3 are rare, and the isotopes of NO– 3 in Antarctica are far from understood. We discuss the spatial distribution patterns of NO– 3 isotopes and possible influencing factors across the Antarctic ice sheet. Furthermore, we summarize the post-depositional processes of NO– 3 in snowpack, and its main mechanisms, and review the available reports on NO– 3 isotope records in Antarctic snow pit and ice cores. Lastly, the main shortcomings of available studies are discussed, and potential research directions on NO– 3 isotopes in Antarctic snow and ice are pointed out. Related Articles | Metrics

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Station characteristics and CSTAR data measurement of LEO space-debris monitoring at Kunlun Station, Antarctica Yang Chenwei, Jiang Peng, Jia Minghao, Zhou Xu, Zhang Shaohua, Zhou Hongyan, Li Gongqiang, Jiang Hai, Cheng Haowen, Liu Jing, Li Zhengyang 2019, 31 (2):  128-133.  DOI: 10.13679/j.jdyj.20180063 Abstract ( 777 )   PDF (4830KB) ( 1055 )   An increasing amount of space debris seriously threatens the operation of spacecraft. Analysis based on objects in LEO Orbit and the geographic position of the Kunlun Station showed that LEO objects have a very high pass frequency and long observable time at Kunlun Station. It is therefore possible to observe larger debris and satellites during polar daytime, as the monitoring efficiency at Kunlun Station is significantly greater than otherwise achievable at other, medium- or low-latitude sites. We analyzed CCD (charge-coupled device) images taken by the Chinese Small Telescope ARray (CSTAR). The line features on the images caused by space debris are effectively detected through use of image subtraction and the Hough transform method. By comparing the detected objects with a published catalog, we found that in a continuous observation time of 72 hours a single telescope with a FoV of 20 deg2 and an effective diameter of 100 mm could detect more than 80% of polar-orbit space debris with a surface area greater than 1 m2. These results confirm the high efficiency of space-debris monitoring at Kunlun Station. References | Related Articles | Metrics

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Using ring width on sagittal plane of otolith to reveal the growth of antarctica fish species: A case study of Electrona antarctica Wei Lian, Zhu Guoping, Duan Mi 2019, 31 (2):  134-143.  DOI: 10.13679/j.jdyj.20180034 Abstract ( 684 )   PDF (1752KB) ( 748 )   Ring width in the sagittal plane of otoliths can be considered as an indicator of fish growth, though this application has not yet been applied to any Antarctic species. Therefore, a case study was made using 50 Antarctic lanternfish Electrona antarctica collected from three locations at the Southern Kerguelen Plateau, Indian sector, in January–February 2016, to investigate the species’ growth. Akaike’s information criterion was used to select the direction of measurement after aging the fish, and the ring width in the sagittal plane was measured in the selected direction. Relationships between opaque rings, translucent rings, and annual rings in the otoliths and the age, standard length (SL), and body weight of fish were fitted with different functions. Relationships between accumulative ring width of the otolith sections and the age, SL, and body weight of fish were also fitted. The results indicated significant difference at the period of 3 years old. E. antarctic rapid growth during the first three years, and thereafter the growth rate decreased. Change in ring width was observed when fish attained sizes of 70 mm SL or 8 g. E. antarctica grew rapidly at smaller sizes, and ring width in the otoliths increased during both winter and summer. This study demonstrated variation in ring width in otoliths with age, SL, and body weight, and thus with life-history stage. To our knowledge, this is the first work to analyze ring width in otoliths in relation to the growth of an Antarctic fish, thereby extending the field of fish otolith research. References | Related Articles | Metrics

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Analysis of meteorological and sea conditions in the Amundsen Sea, Antarctica Qin Ting, Liu Jian, Wei Lixin, Su Bo 2019, 31 (2):  144-156.  DOI: 10.13679/j.jdyj.20180039 Abstract ( 768 )   PDF (10113KB) ( 527 )   This study compared automatic weather station data, manual observation of wave height measured by the RV Xuelong, and ERA-Interim data from the European Centre for Medium-range Weather Forecasts (ECMWF) dataset collected by China’s 34th Antarctic expedition. The correlation coefficients all reached levels of significance. The ERA-Interim data were chosen to analyze climatological characteristics in the Amundsen Sea, including the average 10-m wind field, mean and extreme significant wave heights, extreme wind speed, and mean sea-level pressure. The results show that wind direction in the Amundsen Sea at the middle and high latitudes was stable westward, and wind speed decreased with an increasing latitude. The average wind speed, frequency of strong winds, and extreme wind speed were variable from month to month. The average wind speed and frequency of strong winds were highest in March, followed by in February, and lowest in December and January. Variations of significant wave height corresponded to zonal wind speed, decreasing with an increasing latitude. Likewise, wave height decreased with an increasing latitude. In March, the average significant wave height at 57°–55°S reached more than 4 m, and the frequency of very rough sea at 60°–55°S exceeded 35%. Overall, wind speed and wave height in the Amundsen Sea were relatively high in March, dropping in December–January. References | Related Articles | Metrics

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Spatial distribution and source of metals in surface soils of the forelands of the Austre Lovénbreen and Pedersenbreen Glaciers, Svalbard, Arctic Wang Danhe, Ma Hongmei, Lin Jianwei 2019, 31 (2):  157-167.  DOI: 10.13679/j.jdyj.20180064 Abstract ( 681 )   PDF (2901KB) ( 687 )   Svalbard, an Arctic archipelago, is an important area for research aimed at clarifying the effects of human activities on the global ecological environment. We collected surface soils in the forelands of the Austre Lovénbreen and Pedersenbreen glaciers, to investigate the content and distribution characteristics of several metals (Ni, Pb, V, Cu, Zn, Mn, Al and Fe) in the soil, and the possible sources of these metals. The average content of metals in surface soils at Austre Lovénbreen increased in the order of Cu<Pb<Ni<V<Zn<Mn< Al<Fe, and at Pedersenbreen they increased in the order of Ni<Pb<V<Cu<Zn<Mn<Al<Fe. The coefficients of variation of metals in surface soils of the forelands at Austre Lovénbreen and Pedersenbreen glaciers were 0.13–0.45 and 0.12–0.98, respectively. The average concentrations of Ni, Pb, V, Mn, Al and Fe at Austre Lovénbreen were similar to those at Pedersenbreen, but the average contents of Cu and Zn at the latter glacier were much higher. The high Pb enrichment factor for soil sampled from Pedersenbreen was close to that found in areas of human activity. Principal component analysis showed that Ni, V, Al and Fe in the surface soils of both glacier forelands were mainly associated with parent-rock weathering, whereas Mn likely originated from parent-rock weathering and human emissions. The results also indicated that Pb in the surface soils at Austre Lovénbreen derived from parent-rock weathering, while at Pedersenbreen Pb derived from parent-rock weathering and was augmented by human activities; Cu and Zn in surface soils at Austre Lovénbreen likely originated from parent-rock weathering, while at Pedersenbreen those metals may have originated from elemental fractionation during parent-rock weathering and the transport process. References | Related Articles | Metrics

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GRV 13100: A newly founded enstatite chondrite from Antarctica Xie Lanfang, Chen Hongyi, Miao Bingkui, Xia Zhipeng, Shao Huimin 2019, 31 (2):  168-178.  DOI: 10.13679/j.jdyj.20180006 Abstract ( 731 )   PDF (13792KB) ( 533 )   Chondrites are stony meteorites that can be classified as enstatite chondrites, ordinary chondrites, car-bonaceous chondrites, K and R chondrite groups. Of these, enstatite chondrites are the most reduced. The evolution of highly reduced conditions of nebulae in the early solar system can be revealed by the metal-sulfide and metal-phosphide composition of enstatite chondrites. This study describes the petrology and mineralogy of a newly discovered meteorite, Grove Mountains (GRV) 13100, as determined using EPMA and Raman spectroscopy. The sample consists mainly of chondrules, matrix, and opaque minerals. The mineral composition of the chondrules and matrix are dominated by enstatite (En90.2–99.5 Wo0.1–4.2) and pyroxenitic glass (En85.0–88.8 Wo0.1–4.1); other components include a small amount of albite (Ab91.0–98.3), cristobalite, and forsterite (Fo98.7–99.9). Opaque minerals include kamacite, troilite, perryite, schreibersite, daubreelite, and niningerite. The content of silicon is 2.23–3.90 wt.%. The characteristic of niningerite is richer in MgS than FeS and MnS. According to the chondrule type, texture, mineral group and mineral composition, especially a large amount of highly reduced metal-sulfide, the sample belongs to enstatite chondrites. Based on our work, GRV 13100 is designated as a group EH enstatite chondrite, of thermal metamorphism grade 4, shock metamorphism stage S2, and weathering degree W2. References | Related Articles | Metrics

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Analysis of changes in the Arctic polynya based on AMSR-E remote-sensing data Xie Xiaolei, Wei Yongliang, Zhang Yu 2019, 31 (2):  179-190.  DOI: 10.13679/j.jdyj.20180035 Abstract ( 730 )   PDF (4468KB) ( 973 )   Four types of remote-sensing data, namely: Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) 36 GHz and 89 GHz gridded brightness temperature data and the AMSR-E ice-concentration data retrieved from those bands, combined with two retrieval methods, were used to determine polynyas of the Arctic. Variations in polynyas along the east coast of Siberia and the west coast of Alaska were analyzed using data for January to April during the period 2003–2011. Comparisons were made using the different data and methods. The main results showed that: (1) patterns of variations in the polynyas were similar, but the values differed, as the polynyas derived from the AMSR-E 89 GHz brightness temperature data showed an increasing trend over the long-term, while the results for AMSR-E sea-ice concentration retrieved from the AMSR-E 89 GHz and 36 GHz and the AMSR-E 36 GHz brightness temperature data showed a decreasing trend; (2) high-resolution data could resolve polynyas more precisely, thus obtaining a larger area, and vice versa with low-resolution data; (3) the polynyas retrieved from the ice-thickness approach were larger than that from ice-concentration approach owing to their different delineations of a polynya; and (4) variations in polynya areas revealed differences at a regional level, with more significant differences for areas west of the Bering Strait and weaker difference for areas to the east. References | Related Articles | Metrics

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Response of lower thermospheric neutral wind at Yellow River Station in Arctic to auroral substorm Qin Minghui, Zhang Yange, Ai Yong 2019, 31 (2):  191-197.  DOI: 10.13679/j.jdyj.20180053 Abstract ( 629 )   PDF (1784KB) ( 822 )   To study the behavior of thermospheric neutral wind during the auroral substorm, we used the OI 557 nm interference fringe images measured by all-sky Fabry-Perot interferometer (FPI) during January 25th, 2017 to January 27th, 2017 at Yellow River Station in Arctic to get the horizontal and vertical wind, considering the geomagnetic Kp, AE index and the ion drift velocity, the factor was studied that affected the thermospheric neutral wind during the substorm. The results show that the geomagnetic activity is correlated with the neutral wind in the lower thermosphere. In this observed event, the mean value of horizontal wind is 50 m·s−1 and that of vertical wind is 3 m·s−1 during the geomagnetic calm period. In the geomagnetic active period, the horizontal wind mean 80 m·s−1 ion drag and Joule heating promote the neutral wind movement, the strong geomagnetic activity leads to the vertical wind shear phenomenon, and the ion dragging dominates the neutral wind movement. References | Related Articles | Metrics

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Connotations, driving forces and future prospect of the Antarctic governance regime Wang Wanlu 2019, 31 (2):  198-208.  DOI: 10.13679/j.jdyj.20180037 Abstract ( 829 )   PDF (306KB) ( 817 )   Antarctic governance is a new focus of international cooperation and international relations, and it forms an important part of China’s share in global governance. Antarctic governance regime derives mainly from the Antarctic Treaty System. The Antarctic governance regime is a regime complex, formed by means of accretion and fission in international relations, though the regime partners are meant to share the same core principles and values. The values of the Antarctic governance regime, which mixes public interests and national self-interests, have determined the implications of Antarctic governance regime. However, a combination of power and norms exists to promote changes in the Antarctic governance regime. At present, the power of Antarctic governance appears to be diffusing, while the resource utilization norm is intensifying; thus, the Antarctic governance regime must confront future changes. References | Related Articles | Metrics

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New definition of deuterium excess and its application in polar regions Wang Jiajia, Pang Hongxi, Hou Shugui, Zhang Wangbin, Yu Jinhai, Liu Ke 2019, 31 (2):  209-219.  DOI: 10.13679/j.jdyj.20180069209 Abstract ( 885 )   PDF (3828KB) ( 1027 )   The deuterium excess in water vapor is mainly controlled by non-equilibrium kinetic fractionation during evaporation, while it is generally considered that isotopic equilibrium fractionation occurs during condensation, which has little effect on the deuterium excess in precipitation and water vapor. Therefore, the deuterium excess records of ice cores can be used for quantitative reconstruction of environmental conditions of oceanic moisture sources. In polar regions, the condensation degree of water vapor is higher due to the lower temperatures. The slope of δD and δ18O during the condensation of water vapor is significantly affected by the equilibrium fractionation coefficient related to temperature; thus, the deuterium excess in polar precipitation is actually affected by the equilibrium fractionation coefficient. In addition, with an increase of the condensation degree of water vapor, the δD/δ18O value of water vapor becomes progressively lower, and a nonlinear relationship between δD and δ18O becomes more apparent. This means that the traditional linear deuterium excess (defined as: dexcess = δD – 8δ18O) is also affected by the isotopic value. Consequently, the deficiency of the definition of linear deuterium excess limits the accuracy of quantitative reconstruction of the environmental conditions of oceanic moisture sources. To make up for deficiency in the linear definition, some researchers in recent years have put forward logarithmic and exponential definitions of deuterium excess. This article highlights shortcomings in the traditional linear definition of deuterium excess, introduces the basic principles and advantages of two new definitions, and discusses the progress of research on this topic as well as potential applications to research in polar regions. References | Related Articles | Metrics

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Feeding ecology of Antarctic icefishes (family Channichthyidae): A review Yang Qingyuan, Zhu Guoping 2019, 31 (2):  220-227.  DOI: 10.13679/j.jdyj.20180040 Abstract ( 822 )   PDF (293KB) ( 1327 )   The Antarctic icefishes (family Channichthyidae) are among the dominant species in the Southern Ocean. This group plays a significant role in material circulation and energy flow in the marine ecosystems of the Southern Ocean, and some species are main targets of commercial fishing in the area. Currently, channichthyids have a high commercial value, especially the mackerel icefish Champsocephalus gunnari, spiny icefish Chaenodraco wilsoni, and South Georgia icefish Pseudochaenichthys georgianus, and some have been studied widely. Most studies of channichthyids have focused on age, growth and distribution, and scarce information has been collected on their trophodynamics; furthermore, most research has concerned only commercial species, which hampers our comprehensive understanding of the role of icefishes in the Southern Ocean ecosystem. The present work reviews the available literature on the feeding mechanisms, food composition, and feeding habits of channichthyids, and the prospects for future research. The findings of this review provide basic information useful for regional and international researchers to carry out related research, hopefully motivating further studies on the feeding ecology of channichthyids. References | Related Articles | Metrics

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China established a sodium fluorescence Doppler lidar at Zhongshan Station, Antarctica Huang Wentao 2019, 31 (2):  228-230.  Abstract ( 546 )   PDF (572KB) ( 741 )   Related Articles | Metrics