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30 December 2017, Volume 29 Issue 4 Previous Issue    Next Issue

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Measurement of ice-induced local vibration of R/V Xuelong icebreaker during its navigation in ice-covered fields Ji Shunying, Lei Ruibo, Li Chunhua, Cai Ke 2017, 29 (4):  427-435.  DOI: 10.13679/j.jdyj.2017.4.427 Abstract ( 718 )   PDF (3705KB) ( 922 )   During the navigation of a ship in ice covered regions, the ship hull vibrates owing to various external forces. The hull vibration can affect both the safety of the ship structure and the normal work of its crew. Field measurements of ship hull vibration can be used to analyze accurately the basic characteristics of ship vibration and develop a relationship between vibration and external forces. In this study, vibrations of the scientific investigation ship XUE LONGuelong were measured during the 32nd Chinese  scientific investigation in the Antarctic in 2015—2016. The hull vibrations when navigating in open water were compared with those when in an ice-covered stretch. The measured data were used to analyze the influences of ice thickness, ship speed and ice-breaking mode on the ice-induced hull vibrations. The vibration amplitude was found to increase with both ice thickness and ship speed. Vibrations in the lateral direction dominated in the impact ice-breaking mode, whereas vibrations in the vertical direction dominated in the continuous ice-breaking mode. This study can help both with the measurement of ice-induced vibrations of the ship hull, and with the investigation of ice-induced vibrations in ice field. Related Articles | Metrics

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Study on the method of extracting Arctic melt pond and roughness information on sea ice surface based on UAV observation Wang Mingfeng, Su Jie, Li Tao, Wang Xiaoyu, Ji Qing, Cao Yong, Lin Long, Liu Yilin 2017, 29 (4):  436-445.  DOI: 10.13679/j.jdyj.2017.4.436 Abstract ( 780 )   PDF (5942KB) ( 982 )   Arctic melt pond over sea ice surface is of great significance in the study of Arctic sea ice mass balance and heat and salt balances in the ocean mixed layer. In order to obtain accurate melt pond fraction, this paper proposes a method for extracting Arctic melt pond and roughness information from the sea ice surface based on unmanned aerial vehicle (UAV) observations. We made UAV observations over the sea ice surface in the Canada basin during the 7th Chinese National Arctic Research Expedition. Improvment on the dark-channel- prior defogging algorithm based on the special environment of Arctic, a mosaic process ,melt pond discrimination on the mosaic image , and melt pond fraction calculation were done step by step. Meanwhile, we used three-dimentional aerial-image modeling to calculate the sea ice surface relative elevation and sea ice surface roughness. Study on the relationship of melt pond and sea ice surface roughness distribution showed that areas with higher surface roughness generally have more smaller melt ponds, whereas dissolved and larger melt ponds usually occur in areas with lower surface roughness. Related Articles | Metrics

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Monitoring the changes of ice shelf and glaciers around Zhongshan Station using multiple-source remote sensing data Liu Ruixi, Zhou Chunxia, Liang Qi 2017, 29 (4):  446-453.  DOI: 10.13679/j.jdyj.2017.4.446 Abstract ( 818 )   PDF (10850KB) ( 622 )   The changes of ice shelves and glaciers are major processes for dynamic changes in Antarctica. MODIS L1B 250 m resolution data and Landsat 15 m resolution panchromatic data are used to investigate dynamic changes in the Amery Ice Shelf, Polar Times Glacier, Polar Record Glacier and Dalk Glacier from 2000 to 2016. The changes in area and annual rate of change are analyzed. The results show that the Amery Ice Shelf has grown in extent over the past 16 years and that its front has advanced at a steady rate. The Polar Times Glacier and Polar Record Glacier continued to advance during those years, and an iceberg calved from the Polar Times Glacier in 2007. The area of icebergs in front of the Polar Record Glacier has decreased annually since a calving event in 2014. The Dalk Glacier has alternated between advancing and calving. Related Articles | Metrics

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A transverse Mercator chart suitable for polar regions Wang Haibo, Zhang Hanwu, Zhang Pingping, Wang Jun, Hao Yongshuai 2017, 29 (4):  454-460.  DOI: 10.13679/j.jdyj.2017.4.454 Abstract ( 707 )   PDF (3317KB) ( 825 )   Polar regions are located at high latitudes. And tThere may be several choices for chart projection of polar regions, including Mercator projection, polar stereographic projection, gnomonic projection, Lambert conformal projection and transverse Mercator projection. The Mercator projection introduces an increasingly large deformation near the polar regions and deformation of infinity at the poles on the chart. With polar stereographic projection, the rhumb line is not straight on the chart. Gnomonic projection is not conformal projection, therefore, it is very difficult to measure range and bearing directly on the chart. On a Lambert conformal chart, longitude is represented by angle. With the transverse Mercator projection, almost all lines of latitude and longitude are curved. Hence, none of the aforementioned projection is particularly suitable for safe polar navigation and reliable chart work. To solve the above problems, a false graticules is constructed and the problem of transforming between false and true latitude and longitude is solved. A transverse Mercator chart based on this false graticules is drawn using MATLABatlab. The characteristics of this new type of chart are similar to those of a Mercator chart and there is still deformation distortion in the polar region, but lines of false longitude and false latitude are mutually parallel and respectively orthogonal. Overall, this new type of chart would be convenient for doing polar chart work. Related Articles | Metrics

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Preliminary study on the noise model and stability analysis of the Yellow River GPS station Feng Yu, Wang Zemin, An Jiachun, Liu Zhikang 2017, 29 (4):  461-470.  DOI: 10.13679/j.jdyj.2017.4.461 Abstract ( 680 )   PDF (3417KB) ( 673 )   The GPS station of the Arctic Yellow River scientific research station is located in Svalbard, Norway, and plays an important role in the surveying and mapping of the Arctic research of China. Further research is needed on its stability because the station is built on permafrost limited to polar conditions. In this paper, observations from the Arctic Yellow River GPS satellite observation station, combined with observations from surrounding 14 IGS (International GNSS Service) stations for the same time period, were processed using GAMIT/GLOBK high-precision GPS data processing software. The noise level, the parameters of the time series, and its uncertainty were estimated based on different noise models, and the relationship of the movement trend between the Yellow River GPS station and the IGS stations was analyzed. The results show that the Yellow River Station and the surrounding GPS stations’ time series has white noise and a larger magnitude of flicker noise. Some components of certain stations also have random walk noise. Furthermore, the total noise and parameter uncertainty were underestimated when only white noise was considered. The horizontal and vertical motion trends of the the Yellow River GPS station are consistent with the NYAL station. Only the vertical direction has a difference of 2.15 mm·a–1. Related Articles | Metrics

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Preliminary survey for Rb content around Zhongshan Station in the Larsemann Hills of East Antarctica Li Yan, Huang Feixin, Cheng Yang 2017, 29 (4):  471-476.  DOI: 10.13679/j.jdyj.2017.4.006471 Abstract ( 692 )   PDF (4123KB) ( 647 )   NITON XL3t-500S GOLDD was applied to test bedrock samples outcropping near Zhongshan Station in the Larsemann Hills of Antarctica. Preliminary survey results show apparently enriched rubidium(Rb) contents. Among the 17 tested rock samples, 12 contained around 0.04% Rb, and one contained as much as 0.1%. By analyzing the sample features, and considering the geological characteristics of the Larsemann Hills, we conclude that the enrichment of Rb is related strongly to a biotite-pegmatite dyke formed in the Pan-African period. Furthermore, the larger the grains in the sample, the greater the Rb content. By analogical analysis, we speculate that the Larsemann Hills have big Rb potential. Therefore, it is necessary to carry out the corresponding geological investigation to further our understanding of the causes for and rules governing Rb enrichment in the Larsemann Hills. Related Articles | Metrics

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Validation of ageing Electrona carlsbergi in the South Shetland Islands Liu Zijun, Wei Lian, Zhu Guoping, Zhang Haiting 2017, 29 (4):  477-485.  DOI: 10.13679/j.jdyj.2017.4.477 Abstract ( 700 )   PDF (1641KB) ( 635 )   Electrona carlsbergi is a species of pelagic fish that inhabits the Southern Ocean and has important ecological function. However, to date there have been only a few reports regarding the age of such fish. To determine the age of E. carlsbergi and confirm the method of age determination, the diazone numbers obtained under direct light of 73 sagittal otolith samples from 59 fish samples collected from the South Shetland Islands on January, 2010 are used as evidence of age identification. Because of the accessory and false rings of the sagittal plane, a longitudinal section is more suitable than a transverse one for determining the age of E.carlsbergi.Of the fish whose ages are identified, 67.80% are three or four years old. The Total Concordance (TC), Coefficient of Variation (CV) and Average Percentage Error (APE) are calculated to quantify the accuracy of the age determination. The average of each index is 50.23%, 3.67% and 8.60%, respectively. These three indexes are also used to test the accuracy of different age groups. The results show a negative relationship between CV and TC, whereas APE increases firstly and then decreases. The von Bertalanffy growth function for E.carlsbergi is Lt=7.7154(1-e–0.5373(t+2.7807)). Related Articles | Metrics

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Bacterial community composition and diversity in soils of Deception Island, Antarctic Wang Jian, Sun Yunfeng, Li Chenxi, Wu Yue, Li Yanhong, Yang Zhiwei 2017, 29 (4):  486-495.  DOI: 10.13679/j.jdyj.2017.4.486 Abstract ( 771 )   PDF (855KB) ( 851 )   Un-cultivation and cultivation methods based on 16S rDNA gene sequences were applied to determine the bacterial community composition and diversity in soil from Deception Island, Antarctic. The 16S rDNA clone library analysis revealed that the cloned sequences were assigned to 39 operational taxonomic units (OTUs) in three phyla, namely Actinobacteria, Proteobacteria, and Bacteroidetes. The dominant phyla Actinobacteria and Proteobacteria accounted for 65.25% and 28.81% of the total clones, respectively. The dominant genera of Actinobacteria were Sporichthya, Nocardioides, Conexibacter, Gaiella, and Arthrobacter. The dominant genera of Proteobacteria were Sphingomonas, Thiobacillus, Stenotrophomona, and Thermomonas. A total of 57 isolates were obtained and were assigned to 13 OTUs in four phyla, namely Actinobacteria, Proteobacteria, Bacteroidetes, and Firmicutes. The dominant Actinobacteria and Proteobacteria accounted for 57.89% and 31.58% of the isolates, respectively. The dominant genera were Arthrobacter and Leifsonia from Actinobacteria and Pseudomonas from Proteobacteria. This study provides important insights into soil bacterial diversity and beneficial microbial resources from Deception Island, Antarctic. Related Articles | Metrics

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Preliminary Study on Phylogenetic Diversity of Culturable Bacteria and Nitrogen-fixing Bacteria in Svalbard Glaciers of Arctic Liu Jie, Li Shengnan, Guo Yudong, Zhang Dandan, Wang Nengfei 2017, 29 (4):  496-505.  DOI: 10.13679/j.jdyj.2017.4.496 Abstract ( 716 )   PDF (1237KB) ( 700 )   Five different samples of representative soil and meltwater (MT, AT, TN, BT, MS) were collected from the upstream, midstream and downstream of the Arctic Svalbard glaciers. The culturable bacteria and potential nitrogen-fixing bacteria were counted, enriched and isolated by using LB medium and strict nitrogen-free medium at the low temperature, respectively. After colony observation, preliminary 16S rRNA gene sequencing and nifH -PCR, 48 culturable bacterial strains and 31 potential nitrogen-fixing bacterial strains were selected to examine the phylogenetic diversity based on the almost full-length 16S rRNA gene sequences. The purpose was to obtain a preliminary understanding of the diversity and distribution of these bacteria in this special area, and to provide a basis for further research on their ecological functions. The results showed that the populations of the culturable bacteria in the five samples were ordered as BT > TN > AT > MT=MS. The populations of potential nitrogen-fixing bacteria were ordered as BT > AT > MT > TN > MS. Forty-eight culturable bacteria belonged to 4 phyla (Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes), 7 classes and 14 genera, and their degrees of  diversity were ordered as BT(6 classes, 6 genera)> MT(4 classes, 6 genera)> AT=MS(3 classes, 3 genera)> TN(2 classes, 3 genera). Meanwhile, the majority of culturable bacterial isolates were composed of Pseudomonas of γ-proteobacteria (20.8%, isolated from the AT, BT and MS samples) and Janthinobacterium of β-proteobacteria(35.4%, isolated from the MS sample). The experimental results of the potential nitrogen-fixing bacteria showed that the diversity of 31 strains isolated from the five samples was very low. Of the strains, 90.32% belonged mainly to Pseudomonas(γ- proteobacteria), only 3 strains isolated from the MT and MS samples belonged to Rhizobium (α-proteo¬bacteria), Janthinobacterium (β-proteobacteria) and Arthrobacter (Actinobacteria C), respectively. There was high 16S rRNA gene homology among these potential nitrogen-fixing strains and some related standard-type strains isolated from other extreme environment. In addition, eight strains that showed less than 98.6% 16S rRNA gene-sequence similarity with strains of related type may represent potential novel species in this special ecological environment. Related Articles | Metrics

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Characteristics of winter-spring Arctic sea-ice and its relationship with tropical cyclone in the Northwest Pacific   Gao Qingqing, Wu Huiming, Zhu Tianmao,Xu Changsan, Cao Bing 2017, 29 (4):  506-512.  DOI: 10.13679/j.jdyj.2017.4.506 Abstract ( 752 )   PDF (984KB) ( 837 )   The spatial and temporal characteristics of Arctic sea ice are studied using the monthly data for sea-ice concentration from the Hadley Center, NCEP/NCAR reanalysis data and best-track data from the Regional Specialized Meteorological Center (Tokyo) Typhoon Center of the Japan Meteorological Agency from 1977 to 2011. The relationship between the winter-spring sea-ice variation and tropical cyclone in the Northwest Pacific is discussed. It is found that the variation of winter-spring sea ice in the Arctic has obvious decadal changes and oscillated with a period of  3—4 years from 1965 to 2004. There were significant changes in sea ice in the late 1960s and early 1970s. The connection between sea-ice anomalies and tropical cyclone is more marked in September than in other months. There is a positive correlation between winter-spring sea ice and tropical-cyclone strength. There is a strong negative correlation between winter-spring sea ice and the Western Pacific Subtropical High. When there is more (less) winter-spring sea ice than average, the summer 500hPa geopotential height is lower (higher) than usual in eastern North American, Iceland, the North Pacific and medium-low latitudes. A persistent relevance between winter-spring sea ice and the northern-hemisphere atmospheric circulation is recognized in the following typhoon season. Related Articles | Metrics

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Diagnosis and numerical simulation of the near-surface wind fields at Inexpressible Island in the Ross Sea Yu Haipeng, Hu Haibo, Chen Zhikun, Ding Minghu, Song Yi 2017, 29 (4):  513-521.  DOI: 10.13679/j.jdyj.2017.4.513 Abstract ( 800 )   PDF (17783KB) ( 638 )   The meteorological factors at Inexpressible Island in the Ross Sea, which will be the candidate site of Chinese third perennial Antarctic research station, are introduced in this study. The analysis of observations from the automatic weather station indicates that the area is dominated by winds driven by the katabatic wind in excess of 10.8 m·s–1. The main wind direction is W-NW and the maximum wind speed is in excess of 32.5 m·s–1. In 2013, the lowest wind speeds were in January, November and December(the local summer). Further examination using results from the Polar Weather Research and Forecasting(Polar-WRF) Model based on NCEP Climate Forecast System Reanalysis(CFSR) sea-ice data suggests that the physical characteristics of the katabatically driven winds can be reproduced well. The higher the resolution ratio, the better the characteristics of the wind are simulate. The strong katabatic wind at Inexpressible Island results from topographic forcing. The airstream from the Reeves Glacier is its main source. The horizontal distribution of strong winds is about 50 km. A steep hill between the altitude of 1 400 m and 300 m is the key area accelerating the air flow. Therefore, the usefulness of the wind fields of the model results is verified. Related Articles | Metrics

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Arctic cooperation after the Ukraine crisis: Perspective of complex interdependence Deng Beixi, Zou Leilei, Tu Jingfang 2017, 29 (4):  522-530.  DOI: 10.13679/j.jdyj.2017.4.522 Abstract ( 702 )   PDF (498KB) ( 860 )   The continuation of interstate cooperative ties between conflicting parties in a post-crisis era can be explained definitively by the concept of “complex interdependence”. As the Ukraine crisis drags on and accelerates further, cooperation between Russia and Western countries has not ended altogether. In the Arctic at least, cooperation in such functional domains as search and rescue, fishing, and navigation as well as in the Arctic Council is barely or only slightly affected. This portrays interstate cooperation in the Arctic as a dynamic combination of rupture and continuation. The ongoing political dynamics in the Arctic reflect how a pre-existing situation of complex interdependence can prevent the entire breakdown of interstate relations. It can also avert escalation of a crisis through the approaches of a linkage strategy, agenda setting, and international regimes. At the same time, pre-existing complex interdependence can keep open channels of communication between the conflicting parties and further facilitate the process of re-building confidence. Related Articles | Metrics

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Implementation and enforcement of the Antarctic Treaty System Chen Li 2017, 29 (4):  531-544.  DOI: 10.13679/j.jdyj.2017.4.531 Abstract ( 774 )   PDF (629KB) ( 992 )   The Antarctic Treaty System (ATS), with the Antarctic Treaty as its core, has established extensive in-ternational obligations for all Contracting Members, such as Antarctic demilitarization, environment protection, and the preservation of living marine resources. With unceasing development of the ATS, human activities in Antarctica have also undergone tremendous change, from governmental organized scientific expeditions to diverse human activities that include but are not limited to Antarctic tourism, fishing, and the exploration of living resources. The main principles and rules established by the ATS have been implemented and executed mainly through an inspection mechanism at international level and by adopting the necessary laws and measures at national level. However, the legitimacy and effectiveness of the Antarctic regime continue to be plagued by deficiencies of necessary remedies for the inspection mechanism, an enforcement vacuum regarding non-contracting members arising from the dilemma of personal jurisdiction, and the incapability of law enforcement due to the remote geographic location and hostile natural environment and climate. In facing these challenges, the Antarctic regime should react positively and adopt comprehensive measures such as reinforcing law-enforcement cooperation, improving the Antarctic inspection system, and intensifying the polar education of its citizens. Related Articles | Metrics