Archive

30 December 2019, Volume 31 Issue 4 Previous Issue    Next Issue

---

For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Select

Variation of Arctic Ocean runoff and its correlation with coastal sea ice Qin Kai, Zhang Yu, Gao Guoping, Chen Changsheng 2019, 31 (4):  371-382.  DOI: 10.13679/j.jdyj.20180055 Abstract ( 912 )   PDF (6603KB) ( 1468 )   Arctic runoff is one of the most important sources of freshwater to the Arctic Ocean and an important factor influencing changes in the Arctic. This study analyzes the relationship between sea ice extent and runoff using the National Snow and Ice Center dataset, the Global River Data Center (GRDC) dataset and the Dai and Trenberth global and river runoff datasets from 1979 to 2010. Based on the locations of Arctic estuaries, the study area is divided into the Chukchi Sea Area, the East-Siberian Sea Area, the Laptev Sea Area and the Kara Sea Area. Choosing six of the 12 largest rivers that flow into the Arctic Ocean based on flow characteristics, a Mann-Kendall trend analysis method was used to detect the variations in characteristics and trends of runoff in different sea areas during different seasons. Results show that the seasonal characteristics of all rivers are clear and consistent. Runoff is concentrated from April to November, and the peak flow around June is much larger than runoff in spring and autumn. The peak flow of the Yenisei and Lena rivers is 3–4 times that of the others. The seasonal variation in runoff is obvious. Under the influence of global warming, runoff exhibits a significant growth trend, and runoff increases most in the spring. Runoff to the East Siberian Sea increases the fastest. The spring runoff of the Chukchi Sea is significantly correlated with the start time of sea-ice melting. For every 5.9 km3·a-1 increase in runoff sea-ice melts one day earlier. In contrast, sea-ice melt in the Eastern Siberian Sea is significantly related to summer runoff (August). For every 30.7 km3·a-1 increase in runoff, sea ice melts one day earlier. The maximum daily runoff in August in the Eastern Siberian Sea is significantly correlated with the ice condition. The maximum daily runoff occurs 8 days before the minimum sea-ice extent. Regardless of other factors, for every 15.7 km3·a-1 increase in the maximum daily runoff, the sea ice anomaly decreases by 1%, indicating that runoff promotes the melting of sea ice during the melting ice period, resulting in a reduction in ice conditions. The increase in autumn runoff in the Eastern Siberian Sea accelerates freezing of sea ice during the late freezing period. References | Related Articles | Metrics

Select

Temporal-spatial variability of Chukchi Sea ice area under the influence of Bering Strait throughflow Deng Yongfei, Gao Guoping, Zhang Yu, Chen Changsheng 2019, 31 (4):  383-392.  DOI: 10.13679/j.jdyj.20180060 Abstract ( 818 )   PDF (3864KB) ( 967 )   This study investigates the temporal and spatial variability of sea ice area in the Chukchi Sea from 1991 to 2015 and the impact of Bering Strait Throughflow (BST) using satellite sea ice concentration data obtained from the National Sea and Ice Data Center (NSIDC). Results show that the sea ice area of the Chukchi Sea has decreased at a rate of 0.7 %·a–1, and that sea ice cover has maintained a low stand since 2002. The heat flux of the BST, together with its circulation pattern in the Chukchi Sea, has an important influence on the temporal and spatial variation of Chukchi sea ice. Sea ice area is strongly correlated with the throughflow’s heat flux (R=–0.86). Both the correlation and variation rate are most significant in summer (May-August), indicating that the increase of heat flux can explain the reduction in sea ice area. The area where the sea ice concentration reduced most significantly on both seasonal and interannual scales is likewise attributable to the circulation of BST in the Chukchi Sea. Sea ice reduction is most significant in May to July above the three main pathways of the BST (Herald Canyon, Central Channel, Barrow Canyon). Supporting this causal mechanism, both the sea ice area and concentration have a lag response relative to the BST heat flux. References | Related Articles | Metrics

Select

Study on geological structural characteristics of the southern Wilkes Basin and its surrounding area based on aeromagnetic data Guo Canwen, Xing Zhe, Ma Yong, Fan Miao, Sun Yi, Zhao Xianren 2019, 31 (4):  393-400.  DOI: 10.13679/j.jdyj.20180067 Abstract ( 677 )   PDF (10098KB) ( 385 )   Wilkes Basin is a large subglacial basin located in the hinterland of the Transantarctic Mountains. Because of its special geographical location, the basin plays an important role in studying the formation of the Trans-Antarctic Mountains and, indeed, the geologic evolution of Antarctica as a whole. However, because of the lack of extensive geological and geophysical investigations, the structural characteristics and origin of the basin are still controversial. Based on aeromagnetic anomaly data of the southern Wilkes Basin and surrounding areas, several main faults in this area are identified using a Euler inversion algorithm. The strikes of these faults are mostly nearly north-south, coincident with the direction of the Mertz Fault, which indicates the possibility of fracture control during the evolution in this region. This study is an important reference for future studies of the Wilkes Basin. References | Related Articles | Metrics

Select

Analysis on the simulated pathway of Pacific Summer Water in the Arctic Ocean Qin Yu, Luo Xiaofan, Dong Chunming, Wang Yali, Nie Hongtao, Wei Hao 2019, 31 (4):  401-412.  DOI: 10.13679/j.jdyj.20180074 Abstract ( 797 )   PDF (8283KB) ( 461 )   Based on hindcast simulation of a fine resolution ocean-sea ice model (NAPA1/12), the seasonal variations of the Pacific Summer Water (PSW) over the northwestern Chukchi shelf, the eastern Chukchi slope and the Canadian Basin are evaluated. The path of PSW in the Arctic Ocean is also analyzed. Results indicate that: 1) Over the northwestern shelf and the eastern slope of the Chukchi Sea, late August temperatures in the upper layer are higher than those at the bottom due to the influence of solar radiation following complete melting of the sea ice. With the reinitiation of freezing in October, a warm water mass is maintained below 20m. This warm water is related to the advection of PSW. Over the northwestern shelf, PSW is mainly derived from the summer Bering Sea Water (sBSW). Over the eastern slope, PSW is composed of the Alaska Coastal Water (ACW) and sBSW, in which ACW plays a dominant role early in the water mass’s development. 2) Barrow Canyon is the main oceanic gateway for PSW into the Arctic Ocean. After exiting Barrow Canyon, PSW first intrudes eastward onto the Beaufort Sea shelf west of 144°W in mid-July. In early August, the majority of PSW is transported westward along the Chukchi Sea slope, thereby entering the Canadian Basin in a clockwise direction. 3) PSW in the Canadian Basin is maintained between the depths of 50 and 100 m. In the western basin, PSW exists year round, while in the eastern basin, PSW exists low temperature. References | Related Articles | Metrics

Select

Analysis of the vertical temperature distribution of shallow snow layers near Taishan Station, East Antarctica Zhang Yuzhong, Tang Xueyuan, Dou Yinke, Guo Jingxue, Zuo Guangyu 2019, 31 (4):  413-420.  DOI: 10.13679/j.jdyj.20180075 Abstract ( 823 )   PDF (1405KB) ( 1188 )   Accurate and reliable measurements of near surface ice temperatures provide important inputs to numerical models that assess the mass and energy balances of polar ice sheets. Based on observation data collected from the 10 m temperature chain at Taishan Station during the 32nd Chinese Antarctic Research Expedition during 2015–2016, the high-resolution vertical profiles of snow temperature at Taishan Station was measured for the first time. The daily, monthly and seasonal characteristics of near-surface snow temperatures are discussed. Results show that the characteristics of heat transfer in the firn. Variations in temperature decrease with depth into the firn, while the phase of temperature variations exhibits gradually increasing lag with depth. The peak and trough of temperature fluctuations are delayed by more than 100 days from the near ground to a depth of 10 m. Additionally, there are notable seasonal distinctions in the vertical firn temperature regime. The temperature distribution profiles in winter and summer or spring and autumn are opposite but not completely symmetrical. The amplitude of near-surface temperature fluctuations in the summer is larger than that in winter, and the amplitude of near-surface temperature fluctuations in autumn is higher than that in spring, which is closely related to the heating effect of shortwave radiation and the phase lag of seasonal temperature fluctuations. References | Related Articles | Metrics

Select

Progress in application of quality management system for the airborne ice-sounding raw data Zhang Wenbo, Lang Shinan, Cui Xiangbin, Zhao Yukai, Bao Zhenshan 2019, 31 (4):  421-430.  DOI: 10.13679/j.jdyj.20180057 Abstract ( 763 )   PDF (3351KB) ( 1100 )   Top-quality research requires accurate raw data. In the context of Antarctic research, the extreme polar environment presents a challenge to accurate data collection and quality assurance. However, the quality of raw data directly affects the subsequent series of important scientific investigations. In this study, we evaluate the application of quality management procedures to data collected by the IceBridge project and Snow Eagle 601, which improve the integrity and security of the raw data by acting to protect the data collection and transport process of airborne ice radar data. Recognizing that effective data quality monitoring must also take into account the nature of the data itself, we additionally recommend simultaneous multi-source data collection to monitor and ensure the quality of the collected data by constructing an all-around supervision of the space-time dimension, so as to effectively guarantee the security of the original data throughout its entire life cycle. References | Related Articles | Metrics

Select

Assessing the accuracy of thin ice thickness retrieval by Arctic ship observations Ma Xueyi, Zhao Xi, Qu Meng, Cheng Zian 2019, 31 (4):  431-440.  DOI: 10.13679/j.jdyj.20180070 Abstract ( 777 )   PDF (1601KB) ( 1365 )   In this study, MODIS SIT products derived from three retrieval models under different snow thickness parameterization schemes and two SMOS (Soil Moisture and Ocean Salinity mission) SIT maps released from the University of Hamburg (SSIT-UH) and the University of Bremen (SSIT-UB) are validated against ship-based SIT observations (SIT-OBS) acquired at 512 sites from October 4th to November 5th in 2015, in Beaufort Sea, Arctic. Results showed that the SIT retrievals derived from Model III with input from ship-based snow data observations offer the best performance with the lowest bias of 0.02 m and root-mean-square error (RMSE) of 0.12 m. Model I with the snow-free retrieval model matched quite well with SIT-OBS (R=0.72), and is more accurate under less snowy weather conditions. Model II takes the empirical snow-ice thickness relationship as snow thickness parameterization, and exhibits overall poor accuracy. Results also illustrate that the SSIT-UB retrievals agree better with the observations than SSIT-UH retrievals. Both of these methods are more accurate than Model III SIT retrievals, with a higher correlation and smaller RMSE. These results indicate that MODIS SIT products are not always ideal as the reference in evaluating other SIT results, and there are still some problems in the current MODIS SIT retrieval models that require further improvement. References | Related Articles | Metrics

Select

Analysis of a podded propulsion system of a polar icebreaker and simulation of its control performance Huang Rong, Li Wenming, Yuan Dongfang 2019, 31 (4):  441-446.  DOI: 10.13679/j.jdyj.20180072 Abstract ( 696 )   PDF (2123KB) ( 1133 )   Podded electric thrusters are widely used in icebreakers and can improve overall ship performance, propulsion efficiency and maneuverability, as well as save cabin space and increase payload. Taking the polar research icebreaker Xuelong 2 as an example, this paper analyses the composition characteristics and advantages of the Azipod® podded propeller produced by ABB Company, and introduces the composition of the podded electric propulsion system. The reliability of speed control based on the podded electric control system of the  Xuelong 2 is verified by simulation experiments on abrupt changes in load. References | Related Articles | Metrics

Select

Economic viability of Asia-Europe container transport through Arctic routes based on Arctic sea ice Luo Qiaoyun, Liu Wei, Shou Jianmin 2019, 31 (4):  447-455.  DOI: 10.13679/j.jdyj.20180069447 Abstract ( 808 )   PDF (641KB) ( 1411 )   This study investigates the viability of Arctic navigation based on sea ice. First, the costs of container transport from Shanghai to Rotterdam through Arctic routes using ice-strengthened ships (Arc4, Arc5, Arc7) are compared with that of the traditional Suez Canal Route. Economic indices are annual cargo volume, unit transportation cost and annual profit. Second, the impact of different starting ports and different carrying capacity on the economy of the Arctic routes is analyzed. Results show that among the three types of ice-strengthened ships, the economy of the Arc5 is the best. By offering a large freight volume, this ship reduces the unit transportation cost and greatly increases the achievable annual profit. In terms of Arc7, although its Arctic navigation time has extended, it is economically unsatisfactory due to high building cost. Results vary greatly between ships. In contrast, the impact of ports origin on shipping economy is less than the grade of ice-strengthening on ships. In the 4000–5000 TEU range, the increased carrying capacity provides little impact on the unit transportation cost, but Arc5 can increase the annual profit by more than 50%. References | Related Articles | Metrics

Select

Analysis of human activities in the Antarctic Peninsula region based on satellite AIS data Liu Aobo, Cheng Xiao 2019, 31 (4):  456-463.  DOI: 10.13679/j.jdyj.20180073 Abstract ( 792 )   PDF (2362KB) ( 882 )   Human activities in the Antarctic include scientific investigation, fishing, tourism and exploration. The increasing intensity of human activity presents a challenge to fragile Antarctic ecosystems and environments. Because ships are the main carriers and vehicles of human activities, the trajectory and intensity of these ships directly reflect the scope and intensity of human activities in the Antarctic. This study uses the ship trajectory data obtained by the AIS satellite from June 2015 to May 2016 to perform a theme analysis based on the human activities in the Antarctic Peninsula region. The study found that there are about 426 vessels active in the Antarctic Peninsula region, the main types of which are freighters, fishing boats, passenger ships and sailboats. The length of the vessels is largely between 50 and 100 meters. Seasonal differences in ship activities are significant. Antarctic tourism and scientific research are concentrated in November–March, while fishing vessels maintain a high level of activity throughout the year. According to the analysis of regional traffic intensity, the most popular tourist attraction in the Antarctic Peninsula area is the Lemaire Channel. The number of trips shows a high degree of consistency with the IAATO tourism statistics, so the ship trajectory data can be used as a supplement to the tourism statistics. The analysis of the scientific research activities shows that seven of the ten scientific research stations with the highest ship traffic intensity in the Antarctic Peninsula belong to South American countries. The country with the highest intensity of ship scientific research activity is Argentina, followed by Chile, while China ranks seventh. References | Related Articles | Metrics

Select

Analysis on development trend and designation process of Antarctic Specially Protected Area Li Yubo, Lu Zhibo, Yang Qingshi 2019, 31 (4):  464-472.  DOI: 10.13679/j.jdyj.20180071 Abstract ( 800 )   PDF (1585KB) ( 1232 )   This study summarizes and analyzes materials and academic literature relevant to the Antarctic Treaty Consultative Meeting. Specifically, this study analyzes three aspects of development trends in the Antarctic Specially Protected Areas. In terms of number, Antarctic Specially Protected Areas can be divided into two echelons based on both historical development and comprehensive strength. In terms of the time of designation, the development of protected areas has experienced peak periods, descent periods and steady periods. In terms of spatial distribution, Antarctic Specially Protected Areas are not spatially representative and are most densely distributed in the Antarctic Peninsula and the Ross Sea. Additionally, this study summarizes and provides updates on the Antarctic Specially Protected Area designation process and makes suggestions with regard to future development of the protected areas, especially with respect to China. References | Related Articles | Metrics

Select

Review of ocean acidification processes and changing trends in the Southern Ocean Chen Kui, Qi Di, Chen Liqi 2019, 31 (4):  473-484.  DOI: 10.13679/j.jdyj.20180077 Abstract ( 846 )   PDF (5340KB) ( 1022 )   Integrated studies over the past 30 years have shown that the carbon absorption capacity of the Southern Ocean has declined significantly since the 1990s. But this weakening trend began to change significantly with an increasing trend after 2002, showing a stronger ability to absorb anthropogenic CO2 in the atmosphere, which will be further enhanced with acidification of the Southern Ocean. Observations show that the decline rate of pH in the Open Southern Ocean of 45°—50°S was 0.0007 per year during 1991–2000, and the Ωarag rose at a rate of 0.015 per year. The decline rate of pH increased to 0.0024 per year during 2001–2011, the Ωarag turned to decline at a rate of 0.017 per year. However, regional differences in ocean acidification among the coastal waters of the Southern Ocean are very large and the interaction of various influencing factors is more complex. For example, the pH and Ωarag in Prydz Bay dropped by approximately 0.11 and 0.30, respectively, from 1994 to 2010. Observations collected in the Weddell Sea from 1973 to 2008 show a decrease in pH on the order of 0.0011 units per year in surface waters associated with a reduction in Ωarag at a rate of 0.002 units per year. Based on the in situ observations and remote sensing inversion parameter methods, important progress has been made in assessing the acidification trend of the Southern Ocean from point-line observations to the overall extent of the sea area. Recently improved model simulation results likewise shown good agreement with the observation results in both magnitude and large-scale spatial patterns. This paper also reviews the acidification trend in the Southern Ocean under different scenarios including RCP 8.5 predicted by the Earth System Model (ESM) and the effects of ocean acidification on the ecosystem of the Southern Ocean. Results show that most of the Southern Ocean will be in an aragonite un-dersaturated state by the end of this century, indicating that the acidification progress of the southern ocean will seriously affect the marine biogeochemical changes and damage the ecosystem of the entire Southern Ocean. Therefore, the study of ocean acidification processes, driving mechanisms and prediction, as well as the evaluation of the ecological effects of this acidification in the Southern Ocean have been seriously placed in front of all mankind. References | Related Articles | Metrics

Select

R/V Xuelong 2 handed over for CHINARE(Chinese National Arctic and Antarctic Research Expedition) He Jianfeng 2019, 31 (4):  485-487.  Abstract ( 574 )   PDF (2489KB) ( 916 )   References | Related Articles | Metrics

Select

Chinese Association of Polar Early Career Scientists: Progress and perspective Ding Minghu 2019, 31 (4):  488-489.  Abstract ( 573 )   PDF (629KB) ( 711 )   References | Related Articles | Metrics

Select

International Symposium on Five Decades of Radioglaciology, International Glaciological Society Tang Xueyuan 2019, 31 (4):  490-492.  Abstract ( 546 )   PDF (222KB) ( 834 )   References | Related Articles | Metrics

Select

The XIII International Symposium on Antarctic Earth Sciences (ISAES 2019, SCAR) Cui Xiangbin 2019, 31 (4):  493-496.  Abstract ( 568 )   PDF (5114KB) ( 849 )   References | Related Articles | Metrics

Select

33rd Forum for Research into Ice Shelf Processes Tang Xueyuan 2019, 31 (4):  497-498.  Abstract ( 538 )   PDF (193KB) ( 575 )   References | Related Articles | Metrics