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    30 March 2004, Volume 16 Issue 1 Previous Issue    Next Issue

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    ENHANCED DESTRIPING OF SATELLITE DATA OF ICE SURFACE IN ANTARCTICA
    2004, 16 (1):  1-10. 
    Abstract ( 1191 )   PDF (440KB) ( 1856 )  

    This paper briefly reviews the cause of the striping and then develops a tapered (Chebwin & Kaiser) window finite impulse response (FIR) filter and a constrained least squares FIR filter by reason of the striping of ASTER satellite data. Both filters minimize the stripes in the visible data and simultaneously minimize any distortion in the filtered data. Finally, the results obtained by using these new filtering methods are quantitatively compared with those produced by other destriping methods.

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    DISTRIBUTION OF URANIUM-SERIES ISOTOPES IN THE PRYDZ BAY, ANTARCTICA
    2004, 16 (1):  11-21. 
    Abstract ( 1643 )   PDF (180KB) ( 1628 )  

    The distributions of 234U, 238U, 226Ra, 210Pb and 210Po in the Prydz Bay, Antarctic, 234U/ 238U and 210Po/ 210Pb activity ratios are reported. The results show that the concentration of uranium in surface water is varies from 13.28-14.20 μmol·m -3, with an average of (13.82±0.29) μmol·m -3. The mean values of ( 234U/ 238U) A.R. is 1.14±0.03. Uranium concentration-salinity relation is, U=0.443S-0.988 (r=0.895). The dissolved 226Ra varied from 1.37 to 1.78 Bq·m -3 with an average of 1.55 Bq·m -3. Particulate 226Ra in 5 surface water samples of studied areas range from 0.006-0.035 Bq·m -3 with an average of 0.015 Bq·m -3. The concentration ranges are 0.80-1.52 Bq·m -3 with an average of 1.14 Bq·m -3 for dissolved 210Po, and 1.34-2.15 Bq·m -3 with an average of 1.66 Bq·m -3 for dissolved 210Pb. The 210Po/ 210Pb activity ratios are 0.55-0.84 with a mean ratio of 0.69. The extent of 210Po/ 210Pb disequilibria is discussed. The vertical distributions of dissolved and particulate 210Pb, 226Ra in six layers from upper 200 m depths of ST station and Portioning between dissolved and particulate phases are presented.

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    BEDROCK EXPOSURE AGES IN THE GROVE MOUNTAINS, INTERIOR EAST ANTARCTICA
    2004, 16 (1):  22-28. 
    Abstract ( 1707 )   PDF (281KB) ( 1592 )  

    Exposure ages of bedrock samples taken from two nunataks in the Grove Mountains (GMs), interior East Antarctica, are studied by dating in situ produced cosmogenic 10Be and 26Al. The results indicate that the minimum exposure time of the five samples are all about 2Ma, much older than that of Last Glacial Maximum. This as well as the field observations indicates that the thickness of the interior East Antarctic Ice Sheet (EAIS) had reduced more than 200m since early to middle Pliocene. From then on, even in the period of the Last Glacial Maximum (LGM), the elevation of the interior EAIS is never higher than that of early to middle Pliocene

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    SPATIO-TEMPORAL CHARACTER OF ANTARCTIC SEA ICE VARIATION
    2004, 16 (1):  29-37. 
    Abstract ( 1682 )   PDF (390KB) ( 2565 )  

    Using sea ice concentration dataset covering the period 1968-2002 obtained from the Hadley Center of UK, this paper investigated characters of Antarctic sea ice variations. The finding demonstrated that the change of sea-ice extent is almost consistent with that of sea-ice area in every longitude, so we last choose sea-ice extent 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 inAntarctic Peninsula. In recent 35 years, as a whole, the sea ice in Antarctica decrease distinctly. There are 5 subdivision regions in total considering their different variation. Thereinto, 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 shrinks and area decreases. They are all of obvious 2-3 years and 5-7 years significant oscillation periods. It is of significance for further understanding the sea-ice-air interaction in Antarctic region and discussing the relationship between sea-ice variation and atmospheric circulation.

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    STATISTIC AND SYNOPTIC ANALYSIS ON BLOWING SNOW AND SNOWSTORM IN ZHONGSHAN STATION, ANTARCTICA
    2004, 16 (1):  39-45. 
    Abstract ( 1441 )   PDF (320KB) ( 1624 )  

    Based on data from Chinese Antarctic Zhongshan Station in 2003, local blowing snow and snowstorms were studied by means of synoptic and statistic. The result showed the Characteristics of the wind, temperature and humidity fields, and the related synoptic situations. The method of weather forecasting is also given.

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    COSMIC-RAY EXPOSURE AGES OF THE DIFFERENT METEORITE TYPES AND THEIR COSMOCHEMICAL SIGNIFICANCE
    2004, 16 (1):  46-64. 
    Abstract ( 1424 )   PDF (662KB) ( 1852 )  

    In this review on the bases of knowing data we summarized the classification of meteorite groups, cosmic-ray ages of the different meteorite types from asteroid belt,Moon and Mars. At present there are thirteen well-established chondrites,seven different parent bodies that experienced high temperatures and pervasive melting,and twelve main iron meteorite groups.These meteorite groups were derived from separate parent bodies. In addition to the established groups,there are about ten unique chondrites or chondrite grouplets, and also numerous ungrouped irons and iron grouplets.Up to date, based on cosmic-ray produced nuclides cosmic-ray exposure ages of more than 1600 meteorites have been determined. From the distribution of cosmic-ray exposure ages for many meteorite groups we recognize clusters that can be interpreted as the result of collisions on a parent body releasing large numbers of fragments. The isotopic abundances of rare gases and cosmic-ray exposure ages of asteroid meteorites, planetary meteorites and the Apollo lunar samples applied to clue up and understanding cosmic-ray exposure history of parent bodies of different meteorite types, collision events, the relationship between cosmic-ray exposure ages and heliocentric distance of the parent bodies, irradiation history of precompaction exposure of chondrules, pairing meteorites for the Antarctic meteorites and desert meteorites, the ejection history of planetary meteorites(martian and lunar meteorites), and relative ages of lunar craters and so on.

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    PROGRESS IN THE STUDIES OF SO_4~(2-) CONCENTRATIONS RECORDED IN ANTARCTIC ICE SHEETS
    2004, 16 (1):  65-74. 
    Abstract ( 1268 )   PDF (378KB) ( 1394 )  

    In this paper, the latest progress of the resources, the time and spatial changes of concentrations of SO 2- 4 in the firn and ice of Antarctic ice sheet have been reviewed. The review of SO 2- 4 resources shows that SO 2- 4 is mainly marine and biogenic as well as large volcanic eruptions in origin in Antarctica. The progress in the studies of volcanic eruptions recorded in the Antarctic ice cores has been given special attention. The summarizing of the studies indicates that the deposition differences for any eruption are expected to be high, but in order to obtain a better comparison among different events in a single core or among different cores, a relative deposition may be calculated for the Tambora eruption. Studies show that the volcanic nssSO 2- 4 flux ratio with respect to the Tambora eruption for different Antarctic ice cores can be comparable, which makes it possible to calculate the scale of past volcanic events using the fluxes of nssSO 2- 4 recorded in the ice cores of Antarctica.

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    WATER DEPTH AND TOPOGRAPHY FEATURES OF THE SEA AREA NEARBY ANTARCTIC ZHONGSHAN STATION
    2004, 16 (1):  75-80. 
    Abstract ( 1482 )   PDF (258KB) ( 1885 )  

    The Prydz Bay in the Antarctic,the important supporting sea area when China built Zhongshan Station, is the only way that research ship passes in and out Zhongshan Station. In this paper, according to the sketch of the depth of the water in the Prydz Bay alongshore,we research and analyse the general situation of the topography. The underwater topography in the Prydz Bay is rugged and rough. By the SN direction from the top of the bay,it formed a sea-floor canyon,about 800m depth,which is continuous to the bottom of the ice sheet. The topography of the both sides of the canyon is complicate,and the underwater hills are jagged. In finally,with the suitable depth of water,ice berg which breaks apart from the canyon bypasses the obstacle of the topography,goes away with the wind and ocean current to the west by the canyon.There are few advantageous topography for research ships dropping anchor at the other sea area in the gulf,except the place named Zhongshan Anchorage where ships may drop anchor which is the shallow water of flat ground.

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