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    30 June 2003, Volume 15 Issue 2 Previous Issue    Next Issue

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    SHORT-TERM FLUX AND COMPOSITION OF PARTICULATE ORGANIC MATTER IN PACK ICE OF CHUKCHI SEA IN SUMMER
    2003, 15 (2):  83-90. 
    Abstract ( 1600 )   PDF (311KB) ( 1588 )  

    During the Chinese First Arctic Research Expedition (July September, 1999), short term particulate organic matter flux was studied in the pack ice zone in Chukchi Sea from August 20 to 23. Results of analyzing trap samples show that POC flux was 1.582mg C m -2 day -1 at euphotic layer and 1.339mg C m -2 day -1 at 220m; while mass flux was 8.788mg C m -2 day -1 at euphotic layer and 10.303mg C m -2 day -1 at 220m. It indicates that POC flux level was very low during late summer ice melting season in the pack ice zone in Chukchi Sea, so were biogenic silicon and particulate phosphate flux in that area. Diatom cells were common components in the trap samples, but diatom flux was quite low. A marked feature of the sinking diatom component was that there existed large differences between the dominant species composition at the euphotic layer and that at the deep layer of 220m. Among the sinking diatom cells, Nitzschia cf. seriata, Navicula glacialis and Melosira sp. dominated at euphotic layer, but Leptocylindrus sp. predominated at 220m. In both layers these dominant diatoms accounted for over 70% in the total diatom abundance quantitatively. But the absolute diatom carbon fluxes were only 0.107 and 0.113mg C m -2 day -1 respectively at above two layers. In contrast, the estimated carbon flux of large copepods (>330μm) was high to 108.67mg C m -2 day -1 , making up 95.3% of the total macro zooplankton carbon flux. The fact that apparent carbon flux of macro zooplankton was 2 3 orders magnitude higher than phytoplankton carbon flux, displays an obvious feature of high zooplankton carbon and low phytoplankton carbon in the water column in the ice melting duration in Chukchi Sea. Obviously, the high apparent zooplankton carbon flux was directly relative to the day night vertical movement of zooplankton, not to the actual carbon amount delivered into deep ocean.

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    DYNAMIC ANALYSIS OF CURRENT OVER THE CONTINENTAL SLOPE OF THE EAST BERING SEA IN SUMMER, 1999
    2003, 15 (2):  91-101. 
    Abstract ( 1567 )   PDF (298KB) ( 1570 )  

    Based on CTD data observed in Bering Sea by the Chinese First Arctic Research Expedition from July to September 1999,we analyze the width, speed and flux of current from 58°N to 60°N over the continental slope of the east Bering Sea and draw conclusions as following: (1) In summer,1999, the Bering Slope Current(BSC) enhances west northward, the maximum speed is about 10cm/s near 58°N and up to 30cm/s near 60°N;the width is about 100km near 58°N and increases to about 210km near 60°N; the flux is about 5.3Sv near 58°N and increases to 10.2Sv near 60°N; (2) The inverse flow is east southward between BSC and continent, the width of upper layer is about 70km, speed is about 5cm/s and it extends to the bottom near 58°N, speed decreases and width increases to about 110km near 59°N, this flow is not observed near 60°N; (3)Bering Sea continental break font strengthens the Bering Slope Current.

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    A REVIEW OF THE ICE ALGAL ASSEMBLAGES AND THEIR LIVE HISTORY IN THE ANTARCTIC SEA-ICE ZONE
    2003, 15 (2):  102-114. 
    Abstract ( 1673 )   PDF (436KB) ( 1576 )  

    Combining with the research results obtained from the Great Wall and Zhongshan Stations of China, the thesis reviews the different ice algal assemblages occurring in the Antarctic sea ice and their formation, survival, growth and disappearance, compares the difference between the pack and fast sea ice zones and brings forward some scientific questions which are needed for further research. There are surface, interior, bottom and sub ice assemblages within ice, and each composes of some types. Because of their different physical characteristics, the surface and interior assemblages are important in the pack ice whereas the bottom and sub ice assemblages are more important in the fast ice. There are typical fast ice algal assemblages in the fast ice zone near Zhongshan Station, but with its relatively lower latitude and more favorable environment, the fast ice near the Great Wall Station has some characteristics similar with those of pack ice. There are several mechanisms of phytoplankton incorporated into new ice, including the active movement of some algal species like pennate diatoms. Frazil ice can collect phytoplankton in the upper water column and cause high biomass within new ice in the pack ice zone, but the autumn ice algal bloom in the bottom of the fast ice occurs through the short period growth. The activities are lower during the winter. In spring the ice algae may act as "seeds" in the ice edge depending on the ice algal community structure, environmental factors and grazing pressure within the upper water column. But in the fast ice zone, ice algae trend to sink quickly to the sea floor. Many studies have been done about the ice algal assemblages, but the studies on the ice algal assemblages in winter pack ice are still few. Furthermore, the influence of global change on ice algal assemblages should be paid much attention to in the further.

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    THE BIOGEOCHEMISTRY OF CARBON CYCLE IN SUMMER OF THE PRYDZ BAY, ANTARCTIC Ⅳ:VERTICAL TRANSPORT AND TRANSFORM PROCESS OF ORGANIC CARBON
    2003, 15 (2):  115-120. 
    Abstract ( 1307 )   PDF (115KB) ( 1595 )  

    Vertical transport and transform process of organic carbon in Prydz Bay and its adjacent sea were investigated during CHINARE 15. The results show that the oxygen utilization in upper water for degrading of DOC and POC account for 6.0% and 6.2% of SOU, respectively. Although the degrading of DOC and POC under 100m is stronger than that in upper water, it is not in large scale. This proves that the content of refractory DOC is higher in Prydz Bay. The positive correlation between POC and DOC in the water within 25m shows that part of POC produced in upper water transforms to DOC quickly, and this transformation cannot be ignored.

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    THE RELATIONSHIP BETWEEN AIR TEMPERATURE OF ANTARCTIC PENINSULAR, ANTARCTIC SEA ICE OSCILLATION AND ENSO
    2003, 15 (2):  121-128. 
    Abstract ( 1560 )   PDF (352KB) ( 1736 )  

    The Relationship between air temperature at Antarctic Peninsular, Antarctic sea ice oscillation and ENSO is analysed by using the 6 weather stations observation data on Antarctic Peninsular. The result shows that air temperature variation at the peninsular can be a good reflection of the Antarctic sea ice oscillations, which means a negative correlation between air temperature and sea ice anomaly near Antarctic Peninsular; a positive correlation between air temperature of Antarctic Peninsular and the sea ice anomaly at Ross Sea. When air temperature at peninsular is in its lower (higher) stage, the sea ice near peninsular is normally more heavy (less), air temperature in middle and East Pacific sea surface temperature(SST) is higher(lower), which is connected with ElNino (LaNina). In addition, the air temperature in October has an important reference for predict SST at Nino3 region in next January.

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    IMPACT OF THE ENSO EPISODES ON THE VARIABILITY OF THE ANTARCTIC SEA ICE EXTENT
    2003, 15 (2):  129-137. 
    Abstract ( 1647 )   PDF (421KB) ( 1636 )  

    In this paper, the spreading way in the southern hemisphere that anomalous warm water piled in tropical eastern Pacific is analysed and then impact of ENSO episodes on the variability of the Antarctic sea ice extent is investigated by using a dataset from 1970 to 2002. The analysis results show that in ENSO period the anomalous warm water piled in tropical eastern Pacific is poleward propagation and westward propagation along southern equator current hasn't been discovered . The time of the anomalous warm water poleward propagation is about 1 year or so. ENSO episodes has a close relationship with the sea ice extent in the Amundsen Sea, Bellingshausen Sea and Antarctic Peninsula. Two years after El Nino appears, the sea ice in the Amundsen Sea, Bellingshausen Sea, especially in the Antarctic Peninsula decreases obviously. The process that El Nino influences Antarctic sea ice extent is that the warm water piled in tropical eastern Pacific is propagated poleward along the coast of southern America and causes the anomalous temperature raise near the pole and then lead to the decrease of the sea ice in Amundsen Sea, Bellingshausen Sea and Antarctic Peninsula. The sea ice has decreased obviously since 1980s, which has relevance to the frequent appearance of El Nino.

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    THE SIGNIFICANCES OF THE CENOZOIC SEDIMENTARY ROCKS FOUND IN THE GROVE MOUNTAINS, EAST ANTARCTICA
    2003, 15 (2):  138-148. 
    Abstract ( 1454 )   PDF (454KB) ( 1761 )  

    Antarctic Ice Sheet has been one of the most important components of the global environmental regime ever since its formation in the Antarctic continent from the early Cenozoic. Its dynamic evolution not only controls all the geological processes including weathering, transportation, and sedimentation happened in Antarctic region, but also reflects and partly controls the global change. Therefore, it is of great significance to study its evolutionary history. So far, a lot of efforts have been made in the studying on the reconstruction of Antarctic Ice Sheet evolutionary history. In this paper, the authors reviewed the former research works in different regions over Antarctic continent and its surrounding sub Antarctic off shore continental shelf, slope and rise, and some deep sea basins. By summarizing the achievements so far have been made in the studies upon the Cenozoic sedimentary strata both in the Antarctic continents and the surrounding oceans, we can conclude that a combination of circum-Antarctic, pan Antarctic and basin specific zonations will be necessary to date and correlate sediments and events within and between polar basins and to assess the impact of Anatrctic Cenozoic climate fluctuations on the geological records at hemispheric and global scales in the future. Special significance of the Cenozoic sediments and sedimentary rocks recently found in Grove Mountains of east Antarctica by Chinese Antarctic Exploration Team has been discussed briefly in the end of this paper.

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    MICROWAVE SCATTEROMETER TECHNOLOGY AND APPLICATION IN POLAR REGIONS
    2003, 15 (2):  151-159. 
    Abstract ( 1610 )   PDF (189KB) ( 2275 )  

    As a new technology, microwave scatterometer has been applied in many fields. This paper briefly represents its principle and development of satellite scatterometers, also a algorithm called SIRF(Scatterometer Image Reconstruction with Filter) used to improve the resolution of scatterometer image. Several types of microwave scatterometer are introduced. On the basis of it, the application in the ice sheet and sea ice of polar regions, e.g. sea ice extent mapping, sea ice motion monitoring, sea ice classification and ice sheet onset thaw is described briefly.

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