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30 December 2006, Volume 18 Issue 4 Previous Issue    Next Issue
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VARIATIONS OF WIND AND THEIR RELATIONS WITH FRONTS IN THE SECTION BETWEEN TASMANIA ISLAND AND ANTARCTICA 2006, 18 (4):  235-244.  Abstract ( 1271 )   PDF (1044KB) ( 1857 )   The WOCE consecutive six-year temperature data in the upper layer of a section between Tasmania Island and Antarctica in the austral summers obtained by the French supply/research vessel "l'Astrolabeare" were used to determine the locations of fronts and to analyze their relation to the local variations of wind stress and wind stress curl derived from the ERS-1/2 satellite wind field data.The result shows that the zonal and meridional wind stress of this section has a seasonal cycle with a period of six months and the phase of zonal wind stress lags behind that of meridional wind stress for one month.Wind stress curl has a periodic variation of two months.The magnitude of seasonally meridional migration in the location of the primary Polar Front(PF1) is much less than that of the climatic monthly mean zero wind stress curl,but is near the mean position of zero wind stress curl.In the north of PF1 the Antarctic Surface Water(AASW) subducts as it continuously moves northward,and encounters the Subantarctic Mode Water(SAMW).The obvious difference in the characteristics of AASW and SAMW may result in the formation of the Subantarctic Front(SAF).Convergence is stronger than divergence in the Polar Front Zone(PFZ),indicating that a part of the converging water must come from the cold water transporting northward from south of PFZ and contribute to the formation and maintenance of the lateral temperature gradient of SAF.The negative maximum of the wind stress curl may determine the intensity of the Southern Antarctic Circumpolar Current Front(SACCF):The stronger the Ekman Pumping caused by the negative maximum of the wind stress curl is,the more intense the SACCF is. Related Articles | Metrics

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ORGANIC GEOCHEMISTRY OF PENGUIN ORNITHOGENIC SEDIMENT FROM ARDLEY ISLAND,WEST ANTARCTICA 2006, 18 (4):  245-253.  Abstract ( 1606 )   PDF (736KB) ( 1710 )   We study molecular geochemical compositions of penguin ornithogenic sediment Y2-1 from Ardley Island,West Antarctica.The results showed that nC_(23) was the main n-alkane,which might derive from tundra mosses.The high concentrations of alkenes in sediments suggested slow diagenesis and good preservation of organic matter in the studied area.At the same time,the concentrations of cholestanol and phytol were high.The concentration profiles of cholestanol and cholesterol were similar to those of the bioelements and could be applied as organic proxies for historic penguin populations.C_(18) alkanoic acid was the main acid in the sediments and the concentrations of unsaturated fatty acids were low and C_(18∶2) acid was trace amount in most samples.This might be explained by that the main organic matter source of the sediment was penguin guano and not vegetation.Bile acid exhibited high concentration in the sediments.However,there were only one C_(27) sterene,C_(27) sterol and one C_(27) bile acid in the sediments,which showed that the input of the steroids was simple.High concentrations of the fecal sterol and bile acid and low concentration of sterene showed good preservation of the sterols and bile acids.In summary,the molecular geochemical compositions of the sediments indicated that the sources of the organic matter were relatively simple,and the organic matter was well preserved there. Related Articles | Metrics

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SURFACE RADIATION CHARACTERISTICS AT NY-LESUND OVER THE ARCTIC TUNDRA AREA 2006, 18 (4):  254-264.  Abstract ( 1378 )   PDF (804KB) ( 1821 )   Based on Koldewey Station′s 1993—2003 hourly observational data,this paper conducts a statistical analysis on the radiation characteristics for an arctic tundra region(Ny-lesund island) where our first arctic expedition station(Huanghe Station) is located.Affected by cloudy sky,Ny-lesund′s sunshine percent was only 32.2% even during deep summer.As a result of ice and snow′s melting effect during warm season,surface reflecting ratio was quickly decreasing and surface absorbing radiation and effective radiation were rapidly increasing.The total net radiation was positive during the whole year.Surface absorbing radiation mainly focused in warm season and was absent during cold season.Radiation factors didn′t show clear changing trends though temperature was clear uptrend at Ny-lesund.NCEP/NCAR reanalysis data of the grid closest to Ny-lesund aren′t accurate in keeping consistent changes with the data obtained at Ny-lesund about surface radiation factors. Related Articles | Metrics

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SOURCE AND DISTRIBUTION OF BIOGENIC MATTER IN SEDIMENTS AT STATION OF CHUKCHI SEA AREA 2006, 18 (4):  265-272.  Abstract ( 1534 )   PDF (341KB) ( 1749 )   ediment samples collected at Chukchi Sea and nearby area during CHINARE were analyzed and discussed to search the spatio-temporal and vertical rule of TC、TOC、TP and TN.Contents of TC in sediments range from 0.89% to 2.17%,contents of TN range from(0.24 mg/g) to 1.66mg/g and contents of TP range from 0.15 mg/g to 0.96mg/g.Total carbon of Station C2-1、S11 and M07 is mainly composed of organic carbon,and this result confirms the conclusion that Chukchi Sea area is an efficient carbon accumulation area.The organic carbon of four stations mainly comes from the ocean.There is an obvious positive correlation between TOC and TN at Station P24 and M07,which could indicate the consanguineous relationshi between nitrogen and organic carbon and the existent form of nitrogen is organic nitrogen at Station P24 and M07. Related Articles | Metrics

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STUDY ON THE WEB-ACCESSIBLE CHINESE ANTARCTIC ENVIRONMENT EVALUATION SYSTEM 2006, 18 (4):  273-281.  Abstract ( 1280 )   PDF (166KB) ( 1414 )   This paper focuses on discussing how to define a series of criteria and descriptive template for each Antarctic environmental indicator incorporated into a web-accessible database system called CAEES(Chinese Antarctic Environment Evaluation System),and to automate the real-time CAER(Chinese Antarctic Environmental Report).This system is based on the regular input of evaluation of indicator status by expertise.The system also captures indicator data either dynamically from sensors or by indicator custodians via Internet.Undoubtedly,the CAER is the requirements for Antarctic environment management,monitoring and evaluation stated in the "Madrid Protocol" and other related recommendations. Related Articles | Metrics

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A REVIEW ON THE ORGANIC MATTER IN POLAR SEA ICE 2006, 18 (4):  282-289.  Abstract ( 1645 )   PDF (327KB) ( 2571 )   ea ice is a unique habitat for organisms in polar seas.The composition,distribution and abundance of organisms in sea ice vary on temporal and spatial scales and are controlled by physico-chemical and biological factors in the surrounding environment.This thesis presents an introduction of the significant study on dissolved organic matter(DOM) pools and particle organic matter(POM) in seaice systems.This thesis concludes the study on the main biological assemblages and their roles in sea ice,the mechanism of DOM and POM in the process of origin,transport and translation.The biochemical composition in the organic matter of sea ice(carbohydrate,lipids,EPS) is also discussed.It as well puts forward some scientific questions which are needed for further research. Related Articles | Metrics

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PROGRESS AND PROSPECT IN NUMERICAL MODELLING OF THE ANTARCTIC ICE-SHEET 2006, 18 (4):  290-300.  Abstract ( 1625 )   PDF (488KB) ( 2541 )   The numerical modelling of the Antarctic ice sheet is an important way to improve our understanding of the behavior of the ice sheet.By this way,we can find out some physical mechanism implied in the data of the observations,and extrapolate the ice-sheet evolution of some areas where no observations are available.In this paper,we review the history of the numerical ice-sheet model in Antarctica,and discuss the models used to research the Antarctic ice sheet,especially the 3-D models of the whole Antarctic ice-sheet.In detail,some results of the numerical simulation about Antarctic ice sheet are given.The potential thermomechanical source of instability and the handicaps in model studies are identified and discussed.In conclusion,there is much room for improvement of numerical models of the Antarctic ice sheet. Related Articles | Metrics

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PROGRESS ON THE ANTARCTIC DIGITAL ELEVATION MODEL 2006, 18 (4):  301-309.  Abstract ( 1371 )   PDF (1330KB) ( 2865 )   Firstly,this paper retrospects the history of the research on Antarctic Digital Elevation Model(DEM) with the development of Satellite Altimetry,such as Seasat,Geosat,ERS-1/2 etc.The development of RAMP(Radarsat Antarctic Mapping Project)/DEM is introduced in detail which includes the data compilation and selection,analysis of the resultant DEM.Secondly,Chinese research on Antarctic DEM based on remote sensing data and survey data is introduced.Finally,the prospect of Antarctic DEM is presented with the development of Ice Cloud and Land Elevation Satellite(ICESat) and Cryosat.Although ESA's ice mission Cryosat was lost due to an anomaly in the launch sequence on October 8 of 2005,it is believed that another new Cryosat will be designed in the near future,which will make great contributions to the research on Antarctic DEM. Related Articles | Metrics