Archive

30 June 2007, Volume 19 Issue 2 Previous Issue    Next Issue
---
Contents


For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Contents

Select

SEASONAL VARIATIONS OF SEA ICE COVER IN THE EAST SIBERIAN SEA AND ITS MAIN DRIVING FACTORS 2007, 19 (2):  87-98.  Abstract ( 1518 )   PDF (3875KB) ( 1940 )   Seasonal variation of the sea ice concentration as well as its dynamical and thermodynamical forcing mechanism in the East Siberian Sea are studied in detail using the satellite remote sensing data during 1999—2005 provided by National Snow and Ice Data Center of USA.The analysis for 1999 sea ice condition reveals that the annual variation of sea ice cover can be divided into 5 stages,namely,packed ice,broken belt along the continental slope,western melting,all-sea ice melting and autumn freezing.The annual five stages are distinguishable clearly,although the minimum of the sea ice cover and appearing date are different each year.The freezing period lasted only 1.5 months,whereas the melting process spent about three months.A sea-ice-rupture area happened in May along the continental slope of the East Siberian Sea due to wind field's divergence.However,the wind field went against the sea ice melting and freezing at the rest of 1999.The runoffs,especially from Indigirka River,Kolyma River,Yana River and Lena River,are the key factors for sea ice melting in the East Siberian Sea.The minimum of the sea ice cover appeared in the late September,in which there wasn't sea ice any more along the coast and a large area of open water formed.In the Northern Hemisphere,the solar heating and air temperature rising provided heat energy continuously for the sea ice melting. Related Articles | Metrics

Select

APPLICATION OF ELECTROMAGNETIC-INDUCTION IN THE BALTIC SEA ICE THICKNESS MEASUREMENT 2007, 19 (2):  99-110.  Abstract ( 1864 )   PDF (1492KB) ( 4328 )   Sea ice,as a component of the cryosphere,is very sensitive to the climate change.Study of sea ice physics needs accurate sea ice thickness data.This paper presents an electromagnetic-induction(EM) technique which can be used to measure the sea ice thickness distribution efficiently,and its successful application in Baltic Sea.Based on the electromagnetic field theory and by applying the electrical properties of sea ice and seawater,this technique can detect the distance between the EM instrument and the ice/water interface accurately,so the sea ice thickness can be obtained.Contrastive analysis of the apparent conductivity data obtained by EM and the value of drill-hole at the same position allows a construction of the transformable formula of the apparent conductivity and sea ice thickness,and the verification of the sea ice thickness calculated by this formula indicates that electromagnetic-induction technique is able to measure sea ice thickness with good accuracy.The average relative error between EM measurements and drill holes data was 12%.The statistic of all ice thickness profiles shows the distribution of smooth surface ice in the Bay of Bothnian was 0.4—0.6 m.This result is in consistent with the EM-bird measurement. Related Articles | Metrics

Select

ANALYSES OF SEA FOG AT GREAT WALL STATION,ANTARCTICA 2007, 19 (2):  111-120.  Abstract ( 1981 )   PDF (1456KB) ( 1841 )   The characteristics and the forming mechanics of the sea fog at Great Wall Station is discussed with analyses of the fields of weather elements,the atmospheric stratification and the synoptic situation,statistical analyses of the duration,seasonal and annual variation of the fogs there and case study.It is concluded that most sea fogs there are advection cooling fog,and the basic cause of the fog is the high-frequency northern winds and the great sea surface temperature gradient across the polar front at the Southern Oceans;There are more sea fogs in summer than those in winter with a significant interannual change;the sea fog can occur when the wind speed is between 0 to 17m/s,and the most favorable wind speed is between 3 to 11m/s;the sea fog tends to occur when the air temperature is between-2 to 4℃ and the difference between the air and the sea is 0 to 2℃;there is often a stationary stratification when the sea fog occurs;'High in the east,low in the west' is the main synoptic situation in which the sea fog at Great Wall Station occurs;The duration of the sea fog there depends on how long the high over the Antarctic Peninsula lasts,with an average about ten hours. Related Articles | Metrics

Select

CHARACTERISTICS OF THE MAGNETIC FLUX TRANSFER EVENTS ON APRIL 1 OF 2004 2007, 19 (2):  121-130.  Abstract ( 1180 )   PDF (3296KB) ( 1461 )   Based on the simultaneous FGM observations of 4 Cluster satellites,this paper calculated and analyzed the current density of FTEs occurred between 12:24 and 12:54UT on April 1,2004 by using the Curlometer analyzer.It showed that intense current flows inside the flux tubes with the current density reaching as high as about 10-7A/m2.By Minimum Directional Derivative(or Difference)(MDD) analyzing,it was also found that the FTEs were of the quasi-2D structure,the direction of the current was almost parallel to the plasma flows and the axis of the flux tubes. Related Articles | Metrics

Select

A STUDY ON THE INSECTICIDAL ACTIVITY OF ANTARCTIC EPIPHYTE GLIOCLADIUM CATENULATUM T31 2007, 19 (2):  131-138.  Abstract ( 1287 )   PDF (335KB) ( 1495 )   In this study,the effects of major environmental factors on the growth and insecticidal activity of antarctic fungi Gliocladium catenulatum T31 were investigated.The method of micro-plate was employed.The bioactivity of the strain T31 to Diamondback Moth(Plutella xylostella) was studied with insect mortality as evaluated index.The most insecticidal activity of T31 fermentation broth was 60.42%.After acetic ether extracted T31 fermentation broth repeatedly,dissolved by acetone at the concentration of 0.33mg/mL,the best insecticidal activity of T31 fermentation broth extracts was 82.05% and insecticidal activity of T31 mycelium extracts was 76.92%.The potted experimentation showed that the controlling effect of T31 fermentation broth to Diamondback Moth was 54.2% on the seventh day. Related Articles | Metrics

Select

MINERALOGIC-PETROLOGIC CHARACTERISTICS OF UREILITES AND THEIR HISTORY OF COSMIC-RAY EXPOSURE AGES 2007, 19 (2):  139-150.  Abstract ( 1636 )   PDF (522KB) ( 2187 )   The mineral-petrological characteristics and shocked effects of the monomict and polymict ureilites are studied in this paper.On the basis of Δ17O,δ13C,MgO/(MgO+FeO)mol%,noble gases,abundances and types of pyroxenes in ureilites,we discussed the classification and origin model.Ureilites are ultramafic magmatic rooks and they exhibit some characteristics of both primitive and differentiated achondrites.Ureilites generally originate from a once partially molten,originally chondritic parent body.Most typical ureilites have monomict textures.The Polymict ureilites are a few,their fragmental breccias contain lithic clasts of monomict ureilite material and other materials.The origin model is mainly ultramafic igneous cumulates or partially melted residues. Related Articles | Metrics

Select

IMPLICATIONS FOR ESTIMATING AIR-SEA CO_2 FLUXES IN THE SOUTHERN OCEAN BASED ON SATELLITE DATA AND IN SITU INVESTIGATIONS 2007, 19 (2):  151-157.  Abstract ( 1652 )   PDF (153KB) ( 1991 )   This paper summarizes the importance of air-sea CO2 fluxes assessment in the Southern Ocean for understanding of global carbon cycle and the limitation of in situ measurements in polar regions for such purpose.A method is introduced to calculate air-sea CO2 fluxes in the Southern Ocean using satellite data by referring to the previous achievements on the air-sea CO2 fluxes estimation in the open ocean and taking advantage of the data collected during the past twenty years in Chinese National Antarctic Research Expeditions.Air-sea CO2 flux estimates are based on the empirical relationships derived from sea surface CO2 partial pressure(pCO2) and relative controlling factors.And pCO2 fields are then created by optimum interpolations based on satellite data and compared with in situ investigations. Related Articles | Metrics