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In order to understand the sea ice types and its region of origin frozen in Weddell Sea, 27 ice cores were taken from Weddell Sea, Antarctica during September and October, 2006.Their crystals were analyzed, and their ice forming processes were evaluated based on the crystals.Photos of the thin sections from two whole ice cores, and from polygonal granular superimposed ice were taken as well as corresponding stratigraphy descriptions.Vertical profiles of salinity, density and grain size were also obtained.Based on ice core structural texture, the findings include that: 1) although large and smooth ice floes were selected as the investigation sites, the ice sheet at the sampling position may be formed by rafted ice, consolidated ice ridges and second-year ice which were affected by dynamic and thermodynamic processes together subsequently.Ice formed in pure thermal growth comprises minority.The polygonal granular superimposed ice from refrozen wetted dense snow is one type of the ice in Antarctica.2) Of the all 27 ice cores, the granular, mixed granular-columnar and columnar crystals in sea ice occupy 28.7%, 14.4% and 55.2%, respectively.3) The pure thermal growth ice is predominant in marginal sea ice zone; the rafted ice and consolidated ice ridges, even second-year ice and polygonal granular superimposed ice from dynamic and thermal effects were found in front of Larsen A Ice Shelf; the thermal growth ice froze in the polynyas of Larsen A, and was transferred outwards.
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Antarctic sea-ice oscillation index with a seesaw pattern is defined using NCEP/NCAR reanalysis girds data of monthly Antarctica sea-ice concentration from 1979 to 2002.The relationships between the index of winter and the summer precipitations in China as well as the onset date of the summer East Asia monsoon are presented.The study result shows that the grids of correlation coefficients passed 5% confidence level between Antarctic sea-ice oscillation index and Antarctic sea-ice concentration are more than 1/3 of all grids of Antarctica sea-ice, that means the index can represent 1/3 sea-ice area.The winter index has a significant correlation with abnormal summer(June-August) precipitation in China.The area of positive correlation lies in the Yangtze River basin and its south, and that of negative correlation lies mainly in the north of Yangtze River basin.While the winter index is positive(negative), the onset date of South China Sea monsoon is earlier(later), with a probability of 79%(80%).Consequently, a conceptual model is given in term of discussing the possible process between the winter Antarctic sea ice and the monsoon precipitation in China.
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Penguin and skua in the maritime Antarctic have high salt loadings in the body due to almost exclusive diet consumption of marine invertebrates. How-ever, the storage and turn over of sodium and potassium in these animals are poorly investigated. Here we determined the concentration and microscopic distribution of the two elements in the bones of penguinandskua.The average concentrations of sodium and potassium in penguin bone were comparable with that inskua bone (0.18% and 0.82% for penguin bone; 0.19% and 0.76% for skua bone in dry weight). The ratios of sodium to calciumand potassium to calcium (0.0330 and 0.0075 for penguin, 0.0335 and 0.0082 for skuain average by weight) were some what higher than the reported ratiosforter restrial animals, indicating the semarine animals-bone enrichment of salt. The ratios of sodium to potassiumin average by weight were 6.75 and 4.65 for penguin and skua, respectively. This value is much lower compared with the bulk sea water ratio of about 27.0, implying that potassiumis favorable to residein the bone rather than sodium. Both sodium and potassium were found to significant correlation with the content of organic materials in bone based up on the intensity of native signal determined by electron paramagnetic resonance (EPR). It was estimated that almost all of potassiumis kept with in the organic phases, while about 30% of sodium sstoredin organic phases and the other 70% within mineral phase. Them icroscopic distributions of potassium in the cross-section and/or surface were revealed by synchrotron radiation X-ray fluore scence (SR-XRF) technique. The ratio of potassium to calcium based upon the SR-XRF intensity counter varied considerably from the surface to the interior, and on the surface the highest concentration of potassium was observed in the middle section with decreasing amounts toward the edge. This indirectly documented that exchange of potassium between fluid and bone organic phase may be occur.
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Compared with traditional chemical analysis methods, reflectance spectroscopy has the advantages of speed, minimal or no sample preparation, non-destruction, and low cost.The present study explored the application of the reflectance spectroscopy within near ultraviolet-visible-near infrared region to predict bio-element compositions in the ornithogenic sediments from the maritime Antarctic.A total of 106 samples were taken from four ornithogenic sediment cores on the Ardley Island of Antarctica, 68 samples were used for building calibration equation, and 38 for prediction of nine bio-elements including P, Ca, Cu, Zn, Se, Sr, Ba, F and S.Three multivariate statistical analysis techniques, including stepwise multiple linear regression(Stepwise-MLR), principal component regression(PCR) and partial least squares regression(PLS) were used to develop mathematical relationships between the spectral data and the chemical reference data.The results showed that the regression models constructed by PCR and PLS models have no significant differences, and obviously supervisor to Stepwise-MLR.The correlations between spectra-predicted and chemically analyzed concentrations of nine bio-elements are statistically significant, and the concentration-versusdepth profiles predicted from reflectance spectra using PLS calibration model are consistent with those from actual chemical analysis.These results demonstrated the feasibility of using reflectance spectroscopy to infer bio-element concentrations in the ornithogenic sediments, and thus it is suggested that the reflectance spectroscopy could provide a rapid and valuable technique to indirectly identify whether the sediments were influenced by penguin droppings in the Antarctic region.
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Instrumental neutron activation analysis(INAA) was applied to analyze the bulk, high-volume aerosol samples, collected at Zhongshan Station in the Eastern Antarctica, during 1998-2001, to study the chemical species..A graphical technique was applied to the INAA data.Results showed that Na, Cl, Mg, Ca, Sr, Br, I, Sr and Rb were marine elements while Al, Sc, Fe and Mn were crustal elements.Compared to marine and crustal elements, five elements(Se、Co、Sb、Zn、Cr) were highly abundant in the aerosols collected at Zhongshan station, which indicated that they might come from the petroleum burning, heating and equipment operation.The presence of pollutant elements suggested that human activities have affected the local environments in Antarctica.
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According to palaeoclimatic and modern instrumental data, numerous studies have indicated that the Arctic climate has undergone a significant warming during the past 100 years, and this may lead to significant impact on the fragile lake ecosystem. In this study, we collected a lake sediment core from the Ny-Ålesund of Svalbard and determined the concentrations of four pigments including chlorophyll derivatives, total carotenoids, oscillaxanthin and myxoxanthophyll in the sediments. Combined with other physical and chemical proxies such as calcium carbonate, total organic carbon, biogenic silicon etc., we have reconstructed the historical changes of lacustrine primary productivity in Ny-Ålesund, especially for the past 100 years. The results showed that during the period of Little Ice Age (LIA), the climate was unfavorable for the growth of the lake algae, and thus the lacustrine productivity declined. This result was supported by the relatively low contents of pigment and biogenic silica in the sediments. Incontrast, the contents of total organic carbon (TOC) and sediment pigments increased significantly in the upper 5cm (~1890AD), reflecting the rapid growth of the lake algae, thus the great increase of lacustrine primary productivity, corresponding to the warming climate after LIA. However, the biogenic silica in the upper sediments still had a relatively low level, and this might be related to the growth competition with other algae species. Over the past 100 years, the ratio of Osc/Myxinthe sediments decreased continuously, indicative of durative in crease of myxoxanthophyll in blue-green algal pigments, and this might imply that the human activity had enhanced the nutrition level of the lake in the Arctic region.
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In the past 30 years, alarge-scale change occurred in the Arctic climatic system, which had never been observed before 1980s. At the same time, the Arctic sea ice experienced a special evolution with more and more rapidly dramatic declining. In this circumstance, the Arctic sea ice became a new focus of the Arctic research. The recent advancements about abrupt change of the Arctic sea ice are reviewed in this paper. The previous analyses have demonstrated the accelerated declining trend of Arctic sea ice extent in the past 30 years, based on in-situ and satellite-based observations of atmosphere, as well as the results of global and regional climate simulations. Especially in summer, the rate of decrease for the ice extents was above 10% per decade. In present paper, the evolution characteristics of the arctic sea ice and its possible cause are discussed in three aspects, i. e. the sea ice physical properties, the interaction process of sea ice, ocean and atmosphere and its response and feed back mechanism to global and arctic climate system.
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Antarctic ice microalgae
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Intelligent robot technology has great potential for application in polar scientific expedition. During the 24th Chinese Antarctic Expedition in the summer of 2007/08, our ice-snow surface mobile and low-flying robots were success fully employed for the first time in the Antarctic. This paper firstly gives a brief introduction to the intelligent robot technology developed a broad and used in the Antarctic, then focuses on the ice-snow surface mobile and low-flying robots developed by China as well as their field trials in the Antarctic. Moreover, the authors have considered the potential demand for the intelligent robot technology in China's Antarctic scientific expedition, in the hope of providing some reference for the future development of robot technologies.
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The remote sensing technique is widely used in Polar Regions, and Moderate Resolution Imaging Spectroradiomete (MODIS) is one of the most important satellite sensors in the domain of remote sensing. In this article, MODIS sensor, including the information of its satellites, its system constitutes, its hardware characteristic, its large spectra and usual applications are briefly introduced first. Then, there is a particular introduction of MODIS's use in Polar Regions, which refers to the polar physiognomy, polar atmosphere and polar ocean, with citing many examples. Atlast, views about the development of MODIS and its series sensors in the future, including the improved applications in Polar Regions are given.
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