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Using sea ice concentration dataset covering the period of 1968-2002 obtained from the Hadley Center of UK, this paper investigates characters of Antarctic sea ice variations .The finding demonstrates that the change of mean sea-ice extent is almost consistent with that of sea-ice area, so sea-ice extent can be chosen to go on this research. The maximum and the minimum of Antarctic sea ice appear in September and February respectively. The maximum and the maximal variation of sea ice appear in Weddell Sea and Ross Sea, while the minimum and the minimal variation of sea-ice appear in Antarctic Peninsula. In recent 35 years, as a whole, Antarctic sea ice decreased distinctly. Moreover, there are 5 subdivision characteristic regions considering their different variations. Hereinto, the sea-ice extent of Weddell Sea and Ross Sea regions extends and area increases, while the sea-ice extent of the other three regions contracts and area decreases. They are all of obvious 2-4 years and 5-7 years significant oscillation periods. It is of significance for further understanding the sea-ice-air interaction in Antarctica region and discussing the relationship between sea-ice variation and atmospheric circulation.
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A 51.85 m firn core drilled in Princess Elizabeth Land, Antarctica, during the 1996-1997 Chinese First Antarctic Inland Expedition, has been measured for δ18O and major ions. Based on the high quality data of the seasonal variations of major ions, the firn core was dated with errors within ±3 years. The 51.85 m firn core record extends for 251 years (A. D. 1745-1996). The results of the glaciochemistry data of the firn core show that the mean concentrations of Cl-, Na+ and Mg2+ are similar to those reported from other coastal areas in East Antarctica. However, mean concentrations of Ca2+ are much higher than those reported from other regions, this anomaly phenomenon may be related to the strong local terrestrial sources. It is found that the variations of three kinds of sea salt ions (Cl-, Na+ and Mg2+) in the past 150 years show very similarly rising trends, which may be the results the Southern Hemisphere warming in the past century.
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Based on the sea ice digital videos and photos along the investigation route in the Second Chinese National Arctic Research Expedition (CHINARE) during July and September, 2003, collections of sea ice thickness and concentration in the area of latitude range of 74.11°N - 79.56°N and longitude range of 144.17°W - 169.95°W are finished. This paper discusses the methods of obtaining ice/snow thicknesses from ship-side videos and ice concentrations from aerial photos, and illustrates the measures should be taken in analysis and in-situ investigation processes to improve the reliability of the parameters. The methods in this paper are somewhat universal and can be used in the research of Bohai Sea and Polar Regions sea ice.
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Abstract: A study has been done on the comparison of nesting and feeding behavior, population variances as well as breeding success between two populations of south polar skua (Catharacta maccormicki) from near Great Wall station on Fildes Peninsula and near Zhongshan station in Eastern Larsemann Hills, Antarctica. There are evident differences in their population ecology. The foraging habit is much related to regional ecosystem and food resources near their territorial area. Dependence on human food waste influences skua's diet, which considerably affects their behavior even population variation in both areas. The skuas in Zhongshan Station, could shorten and/or regulate the timing for their egg laying and hatching, and take precedence of one chick brooding, for keeping their breeding success, and subsequent species continuation.
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This paper briefly reviews the cause of the striping and then develops a taped (Chebw in & K aiser) window finite in pulse response (FIR) filter and a constrained least squuares FIR filter by reason of the striping of A STER satellite data . Both filtersm in m ize the stripes in the visible data and simultaneously m in m ize any distortion in the filtered data Fina11y, the results obtained by using these new filtering methods are quantitalively compared with those produced by other destriping methods
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The potential of 324 bacteria isolated from different habitats in polar oceans to produce a variety of extracellular enzymatic activities at low temperature was investigated. By plate assay, lipase, protease, amylase, gelatinase, agarase, chitinase or cellulase were detected. Lipases were generally present by bacteria living in polar oceans. Protease-producing bacteria held the second highest proportion in culturable isolates. Strains producing amylase kept a relative stable proportion of around 30% in different polar marine habitats. All 50 Arctic sea-ice bacteria producing proteases were cold-adapted strains, however, only 20% were psychrophilic. 98% of them could grow at 3% NaCl, and 56% could grow without NaCl. On the other hand, 98% of these sea-ice bacteria produced extracellular proteases with optimum temperature at or higher than 35℃, well above the upper temperature limit of cell growth. Extracellular enzymes including amylase, agarase, cellulase and lipase released by bacteria from seawater or sediment in polar oceans, most expressed maximum activities between 25 and 35℃. Among extracellular enzymes released by bacterial strain BSw20308, protease expressed maximum activity at 40℃, higher than 35℃ of polysaccharide hydrolases and 25℃ of lipase.
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Combined with the current status of Antarctic data management and the characteristics of polar science data resulted from Chinese Antarctic and Arctic Research Expeditions, the Chinese Polar Science Database System (CPSDS) has been designed and established in 2002. The infrastructure, technical standard, mechanism of sharing data of this system are reviewed in this article. Meanwhile, the development of Chinese polar data management is summarized. As the metadata is the powerful and useful tool for managing and disseminating scientific data, the metadata is also used as "search engine" of CPSDS. Besides, the trend of data management and sharing is also discussed.
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It is well known that varying of the sea ice not only in the Antarctic but also in the Arctic has an active influence on the globe atmosphere and ocean. In order to understand the sea ice variation in detail, for the first time, an objective index of the Arctic and Antarctic sea ice variation is defined by projecting the monthly sea ice concentration anomalies poleward of 20°N or 20°S onto the EOF (empirical orthogonal function)-1 spatial pattern. Comparing with some work in former studies of polar sea ice, the index has the potential for clarifying the variability of sea ice in northern and southern high latitudes.
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Climate anomalies in the southern high latitude associated with the Subtropical Dipole Mode (SDM) are investigated using a 23-year database consisting of SLP (sea level pressure), surface air temperature (SAT) and sea surface temperature (SST). The analysis depicts, for the first time, the spatial variability in the relationship of the above variables with the Subtropical Dipole Mode Index (SDI). It suggests that the SDM signal exists in the southern high latitudes and the correlation fields exhibit a wavenumber-3 pattern around the circumpolar Southern Ocean. Lead-lag correlation analysis used to the SLP, SAT, and SST anomalies with the SDI time series at the positive and negative correlation extremes shows that the southern-high-latitude climate responses to SDM almost instantaneously proposing the connection is by atmospheric and not by oceanic propagation.
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