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30 March 2005, Volume 17 Issue 1 Previous Issue    Next Issue
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COMMUNITY STRUCTURE AND BIOMASS OF ICE ALGAE AND PHYTOPLANKTON IN THE LAPTEV SEA(ARCTIC) IN SPRING 2005, 17 (1):  1-10.  Abstract ( 1567 )   PDF (919KB) ( 1616 )   Species composition, abundance and biomass of ice algal and underlying phytoplankton communities were investigated in southeastern Laptev Sea in spring 1999. Diatoms were predominant in algal species and pennate diatoms were dominant in diatom species. 12 dominant algal species occurred in ice and underlying water column, which included Fragilariopsis oceanica, F. cylindrus, Nitzschia frigida, N. promare, Achnanthes taeniata, Nitzschia neofrigida, Navicula pelagica, N. vanhoeffenii, N. septentrionalis, Melosira arctica, Clindrotheca closterium and Pyramimonas sp. The algal abundance within bottom 10cm sea ice were between 14.6 and 1562.2 ×10 4 cells·L -1 with an average of 639.0 ×10 4 cells·L -1 , and the algal biomass were between 7.89 and 2093.5 μg C·L -1 with an average of 886.9 μg C·L -1 , which were about one magnitude higher than those of sub-bottom and two magnitude higher than those of underlying surface water. The integrated algal abundance and biomass within bottom 20cm ice column were averagely 7.7 and 12.2 times as those in underlying 20m water column, respectively, suggesting that the ice algae might play an important role in maintaining the coastal marine ecosystem before the melting of sea ice. The influence of ice algae to the phytoplankton community was obvious although the similarities of algal community in ice bottom and water surface were not high in many sites. But the “seeding” of ice algae to phytoplankton was low because the abundance and biomass in water column were much lower than those in bottom ice and no rapid growth occurred within phytoplankton community. Related Articles | Metrics

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DIFFERENCES OF SEA ICE DISTRIBUTION IN CHUKCHI SEA AND THEIR DYNAMIC MECHANISM IN 1999 AND 2003 2005, 17 (1):  11-22.  Abstract ( 1577 )   PDF (2093KB) ( 1611 )   In this paper,the difference of Chukchi Sea ice distribution in 1999 and 2003 is studied by using the satellite remote sensing data form NSIDC.The results showed that the total sea ice in 2003 was obviously lighter than that in 1999.Sea ice cover was decreased in the spring and autumn of 2003. The sea water coming from Bering Sea passed the Bering Strait and entered into the Chukchi Sea half month earlier than that in 1999,which caused the sea ice melt seriously. However, the increase process of sea ice area was slowed down in July and August of 2003, and the ice area was close to that of 1999. In the autumn, the sea ice freezing process was postponed greatly, at least half month. The difference can better explain the heavy ice we met in 1999 expedition and the moderate ice status in 2003 expedition. The most important reason for lighter ice in 2003 is the higher air temperature (SAT).The SAT in 2003 spring and autumn were much higher than that in 1999, and the highest SAT difference record is about 18°C in coastal area of Alaska. The notable warmer weather provides the extra heat to decrease sea ice in 2003.Another factor acting on Chukchi Sea ice is the difference in wind field between the two years.The water flux from Pacific is greatly affected by the local wind field in both Chukchi Sea and Bering Sea.In 1999, the wind went against the entering of Pacific water in spring,whereas wind in 2003 spring is benefit to the entering.The southern wind occurred in both first few days of November 2003,caused the delay in sea ice freezing in autumn.The disagreement of the meteorologic factors in both years could be attributed to the difference in AO index,a larger scale process. AO index is positive in 2003 and negative in 1999, which determined in great extent the different pattern in both years. Related Articles | Metrics

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POLAR IONOSPHERIC ABSORPTIONS DURING SOLAR STORMS AT THE END OF OCTOBER, 2003 2005, 17 (1):  23-32.  Abstract ( 1675 )   PDF (364KB) ( 1985 )   The technique and data analysis of imaging riometer are presented in this paper. Some absorption effects in polar ionosphere were obtained by means of the imaging riometer at Zhongshan station during solar storms at the end of October 2003. The main features were: a sudden cosmic noise absorption (SCNA) with 2.7 dB and a polar cap absorption (PCA) lasting about 4 days with a peak up to 31 dB. Related Articles | Metrics

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SHORT-TERM CLIMATE CHARACTERISTICS AT THE NY-■LESUND OVER THE ARCTIC TUNDRA AREA 2005, 17 (1):  32-44.  Abstract ( 1562 )   PDF (533KB) ( 1764 )   Based on Germany Koldwey Station′s 1994—2003 conventional observation hourly data, this paper conducts a statistical analysis on the short-term climate characteristics for an Arctic tundra region (Ny-lesund island) where our first arctic expedition station (Huanghe Station) was located. Affected by the North Atlantic warming current, this area has a humid temperate climate, and the air temperature at the Ny-lesund raised above 0℃ even during deep winter season during our research period. The wind speed in this area was low and appeared most at southeast direction. We find that the temperature at Ny-lesund raised in the faster speed (0 68℃/10 a) than at the whole Arctic area. Compared with the expedition results obtained at the floating ices in the Arctic, Ny-lesund was warmer and more humid and had lower wind speed. Comparison of the near surface air temperature derived by NCEP/NCAR reanalysis to the conventional measurements conducted at the Koldwey site in Ny-lesund area shows a good agreement with winter season and a significant difference for summer season. Related Articles | Metrics

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MINERALOGIC-PETROLOGIC CHARACTERISTIC OF METEORITES AND THEIR CLASSIFICATION 2005, 17 (1):  45-74.  Abstract ( 1941 )   PDF (1334KB) ( 3029 )   On the basis of minerologic-petrologic characteristics, chemical compositions,oxygen isotopes and textures meteorites are classified into two major categories : chondrites and nonchondritic meteorites.Chondrite can be further divided into carbonaceous chondrite clan (CI,CM,CO,CR,CB,CH,CV and CK chondrites),ordinary chondrite clan(H,L,LL chondrites), enstatite chondrite clan(EH and ELchondrites),R and K chondrite group, and that nonchondritic meteorites are further classified into primitive achondrites and the igneously differentiated meteorites.Primitive achondrites are including Acpulcoites,Lodranites,Winonaites,IAB silicate inclusions and IIICD silicate inclusions. The igneously differentiated meteorites are classified into achondrites (Angrites,Aubrites ,Branchinites,Ureilites,HEDVista meteorites,SNCO martian meteorites and lunar meteorites),stony irons(mesosiderirtes and pallasites) and iron meteorites(IAB,IC,IIAB,IIC,IID,IIE,IIIAB,IIICD,IIIE,IIIF,IVA and IVB iron meteorite groups).Every meteorite clan or meteorite group have similar origins or formation histories that could be derived same asteroidal or planetary parent body,thereby we can establish possible genetic relationships between various meteorire clans or meteorite groups .These different meteorite clans or meteorite groups may provide informations of physical-chemical conditions and their evolution history of early solar nebula. Related Articles | Metrics

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ADVANCE OF RESEARCH FOR SEA-ICE BACTERIA 2005, 17 (1):  75-85.  Abstract ( 1311 )   PDF (228KB) ( 1960 )   Sea ice provides an extensive but transient habitat for the extensive microbial communities, referred to as uhe sea ice microbial community (SIMC). Bacteria represent a major group within these communities, as evidenced by measures of bacterial production and the microbial loop. They play a fundamental role in polar ecosystems. Apart from their ecological importance, the bacterial species found in sea ice have become the focus for novel biotechnology, as well as for the basic research on life forms diversity. This review introduces the subjects of bacterial phylogenetic diversity, ecophysiology, ecology, and adaptation. But some scientific questions remain and more study should been done in the future. Related Articles | Metrics

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THE PROGRESSES IN CRYOSPHERE SCIENCE——INTRODUCTION OF THE 2004 AGU FALL MEETING 2005, 17 (1):  86-91.  Abstract ( 1389 )   PDF (390KB) ( 1471 )   American Geophysical Union (AGU) Fall Meeting took place on December 13—17 of 2004 in San Francisco, California, USA. More than 11500 scientists attended the meeting. The number of abstracts received by the meeting was about 10690. 23 subjects and 889 sessions were arranged in the meeting. The AGU Meeting is open to all AGU members and those who are interested in the Earth and space sciences. This paper introduced the AGU 2004 Fall Meeting. Some progresses are reviewed on Cryosphere Science (ice sheet/glaciers, sea ice and frozen ground) in this meeting. Related Articles | Metrics