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30 December 2014, Volume 26 Issue 4 Previous Issue    Next Issue

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SUBGLACIAL TOPOGRAPHIC SURVEYS IN THE KERNEL AREA OF THE GROVE MOUNTAINS, ANTARCTICA Wang Zemin, Tan Zhi, Ai Songtao, Liu Haiyan, Wang Liying 2014, 26 (4):  399-404.  DOI: 10.13679/j.jdyj.2014.4.399 Abstract ( 1637 )   PDF (2932KB) ( 1346 )   The Grove Mountains are located in a remote area of inland Antarctica between Zhongshan Station and Ice Dome A. China has organized five scientific investigations in the Grove Mountains, researching geological structure, ancient climate, and meteorites, monitoring ice movement, conducting basic mapping, meteorological observations, and other multi-disciplinary observational studies. During the 26th Chinese Antarctic Research Expedition in 2010, the Grove Mountains investigation team used specialized ground penetrating radar (GPR) for topographic mapping under the ice in the eastern kernel area of the Grove Mountains. In this paper, global positioning system (GPS) and GPR data are processed using professional graphics software to produce two subglacial topographic maps of the Grove Mountains kernel area. The maps revealed the structure of the nunataks and the bedrock in this area, and identified a possible sedimentary basin under the Pliocene epoch fossil ice. In addition, cross-sectional analysis of the area between Harding Hill and the Sakharov Ridge showed that the box valley shape between the two nunataks has already matured. Related Articles | Metrics

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MODELING AND APPLICABILITY ANALYSIS OF EMPIRICAL POLAR IONOSPHERIC TEC MODELS Ning Xinguo, An Jiachun, Wang Zemin 2014, 26 (4):  405-409.  DOI: 10.13679/j.jdyj.2014.4.405 Abstract ( 1737 )   PDF (2298KB) ( 1290 )   Total electron content (TEC) were derived from GPS measurements collected from more than 40 continuously operating stations in Antarctica during 2010, and then were modeled using five commonly used regional models: the poly model (POLY), the generalized trigonometric series function model (GTSF), the low-degree spherical harmonic function model (LSH), the adjusted spherical harmonic function model (ASHF) and spherical cap harmonic analysis (SCHA). The five models were compared with assess their applicability in polar regions. The results showed that all five models performed well in Antarctica, with 0.1 TECU of residual mean value and 2 TECU of root mean square error. Related Articles | Metrics

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ARCTIC SEA ICE CONCENTRATION RETRIEVAL USING HY-2 RADIOMETER DATA Shi Lijian, Wang Qimao, Zou Bin, Shi Yingni, Jiao Min 2014, 26 (4):  410-417.  DOI: 10.13679/j.jdyj.2014.4.410 Abstract ( 2113 )   PDF (4575KB) ( 1479 )   The Chinese marine satellite (HY-2) was successfully launched on 16 August 2011. We investigated an algorithm for sea ice concentration retrieval, based on brightness temperature data from the HY-2 scanning radiometer. In this study, the tie-points for brightness temperatures were selected based on statistical analysis of the polarization gradient ratio and the spectral gradient ratio over typical areas. The thresholds of two weather filters were determined to reduce the atmospheric effect over the open ocean. The total ice concentration over the Arctic in 2012 was calculated and compared with two existing operational data sets from the National Snow and Ice Data Center (NSIDC) and the University of Bremen. The result of the comparison showed that the calculated sea ice concentration from the HY-2 radiometer data were comparable with ideal values from three typical ice regions in the Arctic Ocean. Our results were also in good agreement with two operational products. Our study demonstrated that HY-2 scanning radiometer data and our retrieval algorithm adapted from the NASA algorithm could be used for operational sea ice services in the Arctic Ocean. Related Articles | Metrics

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EXTRACTION OF THE GREENLAND COASTLINE BASED ON TERRASAR-X IMAGERY Sheng Jia, Hong Zhonghua, Zhang Yun, Yuan Guoliang 2014, 26 (4):  418-424.  DOI: 10.13679/j.jdyj.2014.4.418 Abstract ( 1672 )   PDF (3019KB) ( 1352 )   Global climate change will cause changes in coastlines, the boundary between land and sea. Polar regions have the largest glaciers, and melting of these glaciers could lead to rapid changes in coastlines throughout the world. Therefore, research on polar coastlines is important. Satellite images can be used to determine the coastal water boundary line. In this paper, we investigated the coast of Greenland using the Gamma filtering method for speckle preprocessing of Synthetic Aperture Radar (SAR) data. We present a method combining the Support Vector Machine (SVM) and the Canny edge detection operator to extract the coastal water boundary line. Using this approach, the extraction accuracy of the Greenland coastline from TerraSAR-X images was up to 60 percent. Related Articles | Metrics

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THE COMPOSITION AND SOURCE OF ORGANIC CARBON AROUND YELLOW RIVER STATION IN NY-ÅLESUND, THE ARCTIC Li Zhongqiao, Wu Ying, Zhang Jing 2014, 26 (4):  425-432.  DOI: 10.13679/j.jdyj.2014.4.425 Abstract ( 1558 )   PDF (1742KB) ( 1047 )   Samples ofsoils, sediments, and two mosses around China’s Yellow River Station in the Arctic were collected in August 2010. The samples were analyzed for grain size, organic carbon content (OC%), total nitrogen (TN%), isotope of organic carbon (δ13C (‰)), and lignin-derived phenols. The OC% and TN% in soil and sediment samples were linearly correlated (R2=1, p < 0.001), which indicated common sources. The grain size was not the main factor controlling the distribution of OC and TN. Data showed the source of lignin was mosses and non-woody vascular plants. The average degradation indictor (Ad/Al)v for all samples was 1.02. The results indicated that the addition of coal dust might lead to a higher (Ad/Al)v compared with fresh vascular plants. The ratio of CAD to FAD ranged from 0.55 to 4.01, and individual yields decreased from the mosses to the soils to the sediments. This pattern showed an increased digenetic characteristic. We concluded that the sources of organic carbon around Yellow River Station were moss and non-woody vascular plants, and the contribution of coal was difficult to distinguish. Related Articles | Metrics

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INFLUENCE OF CLIMATE CHANGE ON THE DISTRIBUTION AND TRANSPORTATION OF PERSISTENT ORGANIC POLLUTANTS IN MARINE AND TERRESTRIAL ECOSYSTEMS IN POLAR REGIONS Wu Xiaoguo, Xie Zhouqing 2014, 26 (4):  433-440.  DOI: 10.13679/j.jdyj.2014.4.433 Abstract ( 1839 )   PDF (1025KB) ( 1257 )   Global climate change has had profound impacts on the environment of the polar regions, and on the distribution and transport of persistent organic pollutants (POPs) in marine and terrestrial ecosystems. In marine ecosystems, the loss of sea ice and increasing areas of open water have lead to the re-emission of POPs trapped in the ice sheet and the ocean. Furthermore, the decrease in primary productivity caused by climate change, and the impact of this decrease on the performance of the biological pump, have reduced the deposition of POPs in the deep ocean, increasing the biological exposure to these substances. In terrestrial ecosystems, the remobilization of POPs has been driven by changes in temperature and soil organic matter. Related Articles | Metrics

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THE POPULATION DISTRIBUTION, STRUCTURE, AND GROWING CONDITIONS OF ANTARCTIC KRILL (EUPHAUSIA SUPERBA DANA) DURING THE AUSTRAL SUMMER IN THE SOUTHERN OCEAN Shi Yongqiang, Sun Song, Li Chaolun, Tao Zhencheng 2014, 26 (4):  441-450.  DOI: 10.13679/j.jdyj.2014.4.441 Abstract ( 1794 )   PDF (3470KB) ( 1074 )   Antarctic krill (Euphausia superba Dana) were collected in the circumpolar region and in the Prydz Bay region of the Southern Ocean during the austral summer of 2007/2008 and 2008/2009, respectively, using a High Speed Collector and an IKMT net. The spatial distribution, population structure, and growing conditions of E. superba were studied with simultaneously measured environmental parameters. The abundance of E. superba was higher in the Weddell Sea than in Prydz Bay. The abundance of E. superba in both the Weddell Sea and Prydz Bay was lower than the abundance recorded in earlier surveys conducted during the same season (austral summer). Over the study area as a whole, E. superba showed normal growth during the two summer expeditions. However, at some stations, the growth of E. superba was limited, possibly as a result of delayed sea ice retreat or lower chlorophyll a concentrations. Analysis of the population structure of E. superba showed that juvenile krill accounted for a large proportion of the population at stations located near the edge of the sea ice, while adult krill predominated in stations in ice-free areas. This phenomenon reflects the different features of distribution between juvenile and adult krill. The population structure of E. superba varied among study areas, which may have affected the population recruitment. Related Articles | Metrics

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REMOVE OF ECHO INTEGRATION NOISE AND ESTIMATE OF THE ABUNDANCE OF ANTARCTIC KRILL 2014, 26 (4):  451-459.  DOI: 10.13679/j.jdyj.2014.4.451 Abstract ( 1658 )   PDF (10911KB) ( 786 )   The abundance of krill on the continental shelf and slope north of the Antarctic Peninsula was measured during the 28th Chinese Antarctic Research Expedition in the summer of 2011–2012. Acoustic data for the estimation of krill abundance were collected using an EK500 scientific echo sounder installed on the R/V Xuelong, using a 38 kHz operating frequency. However, the data were affected by significant electrical noise that had to be removed before integrating the mean volume backscattering strength (Sv). Noise correction and signal-to-noise-based thresholds were used for post-processing removal of noise from the acoustic data. Cell-size parameters of one ping and 70 samples were used to average the power data, a quantity equivalent to the Sv with no time varied gain applied. The signal-to-noise ratio (SNR) was defined as the original Sv minus the estimated maximal Svnoise, such that 0 dB could be set as the minimum desired SNR. The results showed that the noise power averaged over all transects was −146.47 dB re 1W and the average noise-removal percentage reached 88.3%. The mean biomass and numerical density in the survey area were 27.30 g·m−2 and 2.95 ind·m−2,respectively. This study demonstrates that the R/V Xuelong is a useful platform to study the biomass and distribution of krill using acoustic methods. Related Articles | Metrics

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PROGRESS OF RESEARCH ON BIPOLAR-ICE-CORE-BASED VOLCANIC FORCING INDEX RECONSTRUCTIONS Gao Chaochao 2014, 26 (4):  460-468.  DOI: 10.13679/j.jdyj.2014.4.460 Abstract ( 1634 )   PDF (2655KB) ( 1269 )   Sulfate aerosols from large explosive volcanic eruptions cool the Earth' surface by reflecting and scattering incoming solar radiation. Understanding the climatic impact of past volcanism is vital to evaluate human impacts on climate through greenhouse emissions and land surface modification. Accurate assessment of such contributions depends on the use of robust forcing indices. This paper provides a brief overview of the climatic impacts of volcanic eruptions, and reviews the progress over the past three decades on polar ice-core volcanic records and on volcanic forcing index reconstruction suing these ice cores. This is followed by an in-depth review of the advantages, as well as the limitations and challenges, of using multiple ice cores from polar regions for reconstructing the volcanic history of the late Holocene. Advances in analytical tools and the methodology of volcanic signal extraction, as well as the volcanic forcing index based on multiple bipolar ice cores are further discussed. Finally, perspectives are offered on how future polar ice-core research could improve the development of a volcanic index suitable for state-of-the-art climate models. Related Articles | Metrics

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A SURFACE CLIMATOLOGICAL VALIDATION OF ECMWF ERA-INTERIM REANALYSIS AND NCEP FNL ANALYSIS OVER EAST ANTARCTICA Ma Yongfeng, Bian Lingen 2014, 26 (4):  469-480.  DOI: 10.13679/j.jdyj.2014.4.469 Abstract ( 2253 )   PDF (5065KB) ( 1750 )   The reliability of the European Centre for Medium-range Weather Forecasts (ECMWF) ERA-Interim reanalysis and the National Centers for Environmental Prediction (NCEP) FNL analysis in East Antarctica were investigated by comparing observations of surface pressure, temperature, specific humidity, and winds collected in 2008 along the transverse route from Zhongshan Station to Dome A. Results showed that the surface temperatures of the ERA-Interim reanalysis were closer to observational data than those of the FNL analysis, with a monthly mean absolute deviation <1 °C in Antarctic coastal areas and <2 °C in interior regions. The temperatures of the FNL analysis were significantly warmer than observations on the interior plateau, especially in winter the positive biases can up to 8–10 °C. Therefore, the FNL analysis can not be directly used to study surface temperature change on the Antarctic Plateau. The surface pressures of the FNL analysis were much closer to observations than those of the ERA-Interim reanalysis, with monthly mean biases of ~1 hPa, while the ERA-Interim reanalysis showed a significant systemic low in coastal regions. The annual/seasonal averaged absolute biases of near surface wind speed between the ERA-Interim reanalysis, the FNL analysis, and observations were less than 1 m·s-1 over coastal and katabatic regions, and about 2–4 m·s-1 over the interior plateau, with absolute wind direction biases of <10°. In addition, the ERA-Interim reanalysis described katabatic winds more accurately than the FNL analysis. Related Articles | Metrics

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SEA SURFACE WIND FIELD ANALYSIS IN THE SOUTHERN OCEAN IN 2012 USING ASCAT WIND FIELD DATA ZHANG Ting, ZHANG Jie, YANG Jungang 2014, 26 (4):  481-486.  DOI: 10.13679/j.jdyj.2014.4.481 Abstract ( 1709 )   PDF (4814KB) ( 1131 )   We performed statistical analysis of spatial and temporal distribution characteristics of the sea surface wind field in the Southern Ocean between 55°S and 90°S, using ASCAT scatterometer wind field data for 1 January 2012 to 31 December 2012. The maximum monthly mean wind speed of 12 m·s−1 occurred in July. The minimum monthly mean wind speed of 8 m·s−1 occurred in December. The monthly mean wind speed was higher in winter than in summer. The regional average wind speed was between 9 and 12 m·s−1, and occurred on more than 280 days in 2012. The number of days with wind speed >10 m·s−1 was higher in winter than in summer. During 2012, the wind speed in winter (April to June) and spring (July to September) was higher than in summer (October to December) and autumn (January to March). The wind speed in the area between 0°W and 60°W was lower than in other parts of the Southern Ocean. Related Articles | Metrics

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ANALYSIS OF OCEANNIC AND METEOROLOGICAL ELEMENTS WHEN R/V XUELONG IN THE ANTARCTIC PACK ICE ZONE IN EARLY JANUARY 2014 Zhang Lin, Li Chunhua, Cai Xianming, Wei Lixin, Li Ming, Sun Qizhen, Li Zhiqiang, Zhao Jiechen, Zhao Biao, Liu Fubin, Tian Zhongxiang, Meng Shang, Sun Hulin, Ma Jin, Su Bo, Yu Haipeng, Liu Yang 2014, 26 (4):  487-495.  DOI: 10.13679/j.jdyj.2014.4.487 Abstract ( 1576 )   PDF (10037KB) ( 801 )   The R/V Xue Long icebreaker was trapped in Commonwealth Bay, Antarctica, after taking part in the rescue of passengers from the Russian vessel Akademik Shokalskiy in January 2014. Monitoring of sea ice information and accurate weather forecasting were key to the successful breakout of the vessel. We conducted a comprehensive analysis of the sea ice, meteorological, and oceanographic conditions to determine the reasons for the vessel becoming trapped. First, sea ice conditions were complex in the area, where first-year ice was mixed with multi-year ice. The area was closed to the continental shelf and was surrounded by large icebergs. Second, continuous strong easterly winds associated with a number of cyclones caused the sea ice to move westward and to accumulate in the area. Related Articles | Metrics

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DIETARY SURVEYS OF THE 22ND AND 24TH CHINESE WINTER-OVER EXPEDITIONERS AT ZHONGSHAN STATION RESIDENCE Chen Nan, Jin Wei,Tang Depei, Zhang Liwei, Xu Chengli 2014, 26 (4):  496-501.  DOI: 10.13679/j.jdyj.2014.4.496 Abstract ( 2023 )   PDF (598KB) ( 1197 )   Aim: For expeditioners in the extreme environment of Antarctica, diet and nutrition are particularly important. Through investigation of the diet of Chinese winter-over expeditioners at Zhongshan station, we can provide advice and guidance to improve dietary quality and to promote health. Methods: The 3- to 4-day food intake of 22nd (2006) and 24th (2008) Chinese winter-over expeditioners was investigated using weighing methods. The average daily intake of food and nutrients was calculated. Dietary status was evaluated according toChinese Dietary Reference Intakes. Results: The average energy intake was in the range for people engaged in moderate or heavy physical labor (2700–3200 kcal). Among the 17 nutrients tested, the intakes of calcium, vitamin A, vitamin C, and selenium were below the recommended daily intake, while the intake of sodium exceeded the recommended daily intake. The intake of oil and salt was excessive. The energy supplied by fat and protein exceeded the recommended 20–30% and 12–14% of total daily kilocalories, respectively, while the ratio supplied by carbohydrates was less than recommended. Conclusions: The diet of winter-over expeditioners was high in fat, high in protein, and low in carbohydrates. There was an excessive intake of oil and dietary sodium, and an insufficient intake of calcium, vitamin A, vitamin C, and selenium. The diet should be adjusted by balancing the proportions of the three major nutrients, reducing the intake of oil and dietary sodium, and supplementing of vitamins, calcium, and selenium. Related Articles | Metrics

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POLAR GAS HYDRATE EXPLORATION AND DEVELOPMENT Wang Pingkang, Zhu Youhai, Zhao Yue, Liu Jianmin, Zhang Xuhui 2014, 26 (4):  502-514.  DOI: 10.13679/j.jdyj.2014.4.502 Abstract ( 2153 )   PDF (4877KB) ( 2008 )   Gas hydrates in the polar regions exist in sediments or sedimentary rocks on the continents and in adjacent offshore areas. The distribution of gas hydrates is closely related to the permafrost area. The potential of the gas hydrate resource in the polar regions is very large. Gas hydrate occurs mainly in sand-rich reservoirs, which provide the high permeability required for a mass accumulation of gas hydrates. With global warming, accelerated melting of sea ice and opening of waterways in the Arctic Ocean will facilitate the exploration and exploitation of the rich resources in these areas. However, there is the potential for dispute among countries wishing to exploit this resource. This paper reviewed the status of polar gas hydrate exploration and the development of relevant national policies. Based on the current status of gas hydrate exploration and development in China, we present ideas and suggest ways of participating in polar gas hydrate research and development to provide a reference for China’s polar resource development and utilization strategy. Related Articles | Metrics

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A COMPARATIVE STUDY OF THE ADMINSTRATION FOR THE NORTHWEST PASSAGE AND NORTHERN SEA ROUTE Zou Leilei, Huang Shuolin, Fu Yu 2014, 26 (4):  515-521.  DOI: 10.13679/j.jdyj.2014.4.515 Abstract ( 1785 )   PDF (629KB) ( 4402 )   Canada and Russia act as the de facto executive body for the Northeast Passage and Northern Sea Route, respectively. A comparative study will be conducted to explore similarities and differences in the administration for Arctic waterways by the two countries. The comparative study will provide insight into similarities and differences in sovereignty claims for Arctic waterways, priority for sovereignty claims or profit claims, and attitudes towards the prospects of commercial shipping in the Arctic waterways. Furthermore, the comparative study will identify differences in attitudes towards the importance of the Arctic waterways to national security, as well as different attitudes towards the environmental protection of Arctic waters. A good understanding of the administration for Arctic waterways will facilitate the understanding of current and future policies for Arctic passages of both countries. As a result, the international community will be well informed and well prepared for the future commercial shipping in the Northwest Passage and the Northern Sea Route. Related Articles | Metrics

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ANALYSIS ON THE PROBLEMS WITH THE “GENERAL FRAMEWORK FOR THE ESTABLISHMENT OF CCAMLR MARINE PROTECTED AREAS” Yang Lei,Han Zixuan, Chen Danhong, Long Wei, Fang Lijun, Li Chunlei 2014, 26 (4):  522-534.  DOI: 10.13679/j.jdyj.2014.4.522 Abstract ( 2027 )   PDF (676KB) ( 2173 )   After years of preparation, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) adopted a General Framework for the Establishment of CCAMLR Marine Protected Areas (MPAs) with the aim to provide a legal framework for the deliberation by members on the establishment of MPAs in the Convention Area in the absence of identification of conservation needs and systematic argumentation from the aspect of science, leaving behind the ambiguity with and even disputes over many critical scientific and legal issues. Due to the limited time for consideration and the intervention of political elements, such a General Framework was adopted with problems in its legal structure, scientific basis and management, monitoring, review process and many other aspects, which lead to a series of divergent ideas and views in the discussions over the specific proposals on the establishment of MPAs. Therefore, the urgent priority for CCAMLR should be creating a fair and transparent condition and atmosphere to facilitate the optimization of the regime on the establishment of MPAs from legal, science and technical respect, with due respect to the Convention for the Conservation of Antarctic Marine Living Resources (the Convention) and the current legal regime and practice, and on the basis of scientific consensus, thus to provide members with a viable foundation for the MPAs deliberations. Related Articles | Metrics