Amery ice shelf DEM and its marine ice distribution

1 Introduction The Amery Ice Shelf, the largest ice shelf in East Antarctica, has a total surface area of about6.1×104km2. The ice shelf drains the grounded ice fromthe interior of the Lam- bert Glacier drainage basin thatcovers an area of larger than1.3…     

The progress in the study of Arctic pack ice ecology

The sea ice community plays an important role in the Arctic marine ecosystem. Because of the predicted environmental changes in the Arctic environment and specifically related to sea ice, the Arctic pack ice biota has received more attention in recent years using modem ice-breaking research vessels. Studies show that the Arctic pack ice contains a diverse biota and besides ice algae, the bacterial and protozoan biomasses can be high. Surprisingly high primary production values were observed in the pack ice of the central Arctic Ocean. Occasionally biomass maximum were discovered in the interior of the ice floes, a habitat that had been ignored in most Arctic studies. Many scientific questions, which deserve special attention, remained unsolved due to logistic limitations and the sea ice characteristics. Little is know about the pack ice community in the central Arctic Ocean. Almost no data exists from the pack ice zone for the winter season. Concerning the abundance of bacteria and protozoa, more studies are needed to understand the microbial network within the ice and its role in material and energy flows. The response of the sea ice biota to global change will impact the entire Arctic marine ecosystem and a long-term monitoring program is needed. The techniques, that are applied to study the sea ice biota and the sea ice ecology, should be improved.     

Determination of ice thickness, subice topography and ice vol-ume at Glacier No. 1 in Tien Shan, China by ground penetrating radar

We describe a radio-echo sounding (RES) survey for the determination of ice thickness, subglacial topography and ice volume of Glacier No. 1 , in Tien Shan, China, using ground-penetrating radar (GPR). Radar data were collected with 100-MHz antennas that were spaced at 4 m with a step size of 8 m. The images produced from radar survey clearly show the continuity of bedrock echoes and the undulation features of the bedrock surface. Radar results show that the maximum ice thickness of Glacier No. 1 is 133 m, the thickness of the east branch of Glacier No. 1 averages at 58. 77 m while that of the west branch of Glacier No. 1 averages at 44. 84 m. Calculation on ice volume indicates that the ice volume of the east branch of Glacier No. 1 is 51. 87 × 106 m3 and that of the west branch of Glacier No. 1 is 20. 21 × 106 m3. The amplitude of the undulation of the bedrock surface topography revealed by radar profiles is larger than that of the glacier surface topography, indicating that the surface relief does     

Crystals and fabrics analysis of an Arctic thermal growth multi-year ice sample

One of sea ice core samples was taken from Arctic by the First Chinese National Arctic Research Expedition Team in 1999. 20 vertical and 2 horizontal ice sections were cut out of the ice core sample 2.22 m in length, which covered the ice sheet from surface to bottom except losses for during sampling and section cutting. From the observation and analysis of the fabrics and crystals along the depth of the ice core sample, followings were found. Whole ice sheet consists of columnar, refrozen clastic pieces, granular, columnar, refrozen clastic pieces, granular, columnar and refrozen clastic pieces. This indicates that the ice core sample was 3-year old, and the ice sheet surface thawed and the melt water flowed into ice sheet during summer. Hence, the annual energy balance in Arctic can be determined by the ice sheet surface thawing in summer, and bottom growth in winter. The thickness of the ice sheet is kept constantly at a certain position based on the corresponding climate and ocean conditions; A new     

Interaction between sea ice/iceberg and ship structures: A review

For ship structural design and good maneuverability in an ice-covered sea, the local and global load of ice cover on ships should be well understood. This paper reviews the extensive work done on ice loads on ships, including： （a） Ice pressure and local load determination based on field and model tests; （b） Global ice loads on ships from full-scale field observations, model tests and numerical models under different ice conditions （level ice and pack ice） and ship operations （maneuvering and mooring）. Spe- cial attention is paid to the discrete element simulation of global ice loads on ships; and （c） Analytical solutions and numerical models of impact loads of icebergs on ships for polar navigation. Finally, research potential in these areas is discussed.     

Model simulations of the annual cycle of the landfast ice thickness in the East Siberian Sea

The annual cycle of the thickness and temperature of landfast sea ice in the East Siberian Sea has been examined using a one-dimensional thermodynamic model. The model was calibrated for the year Augus...     

Genetic types and characteristics of ground ice in Northeast China

１ＧＥＮＥＴＩＣＴＹＰＥＳＯＦＧＲＯＵＮＤＩＣＥＩＮＣＨＩＮＡＧｒｏｕｎｄｉｃｅｉｓｗｅｌｄｅｖｅｌｏｐｅｄｉｎｔｈｅｖｉｃｉｎｉｔｙｏｆｔｈｅｓｏｕｔｈｅｒｎｐｅｒｍａｆｒｏｓｔｌｉｍｉｔｉｎｔｈｅＥｕｒａｓｉａｎｃｏｎｔｉｎｅｎｔ,ｉｎｔｈｅｎ...     

Isolation of novel psychrophilic bacteria from Arctic sea ice

The phylogenetic diversity of cuhurable psychrophilic bacteria associated with sea ice from the high latitude regions of Canadian Basin and Chukchi Sea, Arctic, was investigated. A total of 34 psychropilic strains were isolated using three methods of （ Ⅰ ） dilution plating （ at 4 ℃ ）, （ Ⅱ ） bath culturing （ at - 1 ℃ ） and dilution plating, and （ Ⅲ） cold shock （ -20 ℃ for 24 h）, bath culturing and dilution plating under aerobic conditions. Sea-ice samples were exposed to -20 ℃ for 24 h that might reduce the number of common microorganisms and encourage outgrowth of psyehrophilic strains. This process might be able to be introduced to isolation psychrophilic bacteria from other environmental samples in future study. 16S rDNA nearly full-length sequence analysis revealed that psychrophilic strains felled in two phylo- genetic divisions, γ-proteobacteria （in the genera ColweUia,Marinobaeter、Shewanella,Glaciecola,Marinomortas and Pseudoalteromortas ） and Cytophaga-Flexibacter-Baeteroides （ Flavobacterlum and Psyehroflexus）. Fifteen of bacterial isolates quite likely represented novel species （16S rDNA sequence similarity below 98% ）. One of strains （BSi20002） from Canadian Basin showed 100% sequence similarity to that of Marinobacter sp. ANT8277 isolated from the Antarctic Weddell sea ice, suggesting bacteria may have a bipolar distribution at the species level.     

Spatial-temporal characters of Antarctic sea ice variation

1　Introduction Nowadaysglobalclimatechangehasbeenanimportantissueintheworld.Antarctic areaisjustthekeyandsensitiveregion,fromwhichscientistsaretryingtheirbesttofind theomenofglobalclimatechange.Andfortherevolvingglobalatmosphere,PolarRegions arecoldsource.TheoceanicandatmosphericconditionofPolarRegionsisimportantto globalatmosphericcirculationandclimatechange.Antarcticareaisoneofthecoldsources ofglobalearth atmospheresystem,whileequatorialareaisitsmainheatsource(seeZhou andLuetal.1996).…     

Analysis of multi-dimensional SAR for determining the thickness of thin sea ice in the Bohai Sea

Flat thin ice (<30 cm thick) is a common ice type in the Bohai Sea, China. Ice thickness detection is important to offshore exploration and marine transport in winter. Synthetic aperture radar (SAR) can be used to acquire sea ice data in all weather conditions, and it is a useful tool for monitoring sea ice conditions. In this paper, we combine a multi-layered sea ice electromagnetic (EM) scattering model with a sea ice thermodynamic model to assess the determination of the thickness of flat thin ice in the Bohai Sea using SAR at different frequencies, polarization, and incidence angles. Our modeling studies suggest that co-polarization backscattering coefficients and the co-polarized ratio can be used to retrieve the thickness of flat thin ice from C- and X-band SAR, while the co-polarized correlation coefficient can be used to retrieve flat thin ice thickness from L-, C-, and X-band SAR. Importantly, small or moderate incidence angles should be chosen to avoid the effect of speckle noise.     

Seasonal change of ice algal and phytoplankton assemblages in the Nella Fjord near Zhongshan Station, East Antarctica

The ice algal and phytoplankton assemblages were studied from Nella Fjord near Zhongshan Station, East Antarctica from April 12 to December 30, 1992. Algal blooms occurred about 3 cm thick on the bottom of sea ice in late April and mid November to early December respectively, and a phytoplankton bloom appeared in the underlying surface water in mid December following the spring ice algal bloom. The biomass in ice bottom was 1 to 3 orders of magnitude higher than that of surface water. Amphiprora kjellmanii, Berkeleya sp., Navicula glaciei, Nitzschia barkelyi, N. cylindrus /N. curta, N. lecointei and Nitzschia sp. were common in the sea ice temporarily or throughout the study period. The biomass in a certain ice segment was decreased gradually and the dominant species were usually succeeded as the season went on. Nitzschia sublineata and Dactyliosolen antarctica were two seasonal dominant species only observed in underlying water column. The assemblages between bottom of ice and underlying surface water were different except when spring ice algae bloomed. The evidence shows that the ice algal blooms occurred mainly by in situ growth of ice algae, and the phytoplankton bloom was mostly caused by the release of ice algae.     

Summer fast ice evolution off Zhongshan Station,Antarctica

Based on the field data acquired in the program of fast ice observation off Zhongshan Station, Prydz Bay, East Antarctica during the austral summer 2005/ 2006, physical properties evolution of fast ice during the ice ablation season is analyzed in detail. Results show that the annual maximum ice thickness in 2005 occurred in later November, and then ice started to reek, and the ablation duration was 62 days; sea water under the ice became warmer synchronously; corresponding to the warming sea ice temperature, a ＂relative cold mid-layer＂ appeared in sea ice; the fast ice marginal line recoiled back to the shore observably, and the recoil distance was 20.9 km from 18 December 2005 through 14 January 2006. In addition, based on the data of sea ice thickness survey along the investigation course of MV Xuelong on December 18 of 2005, the ice thickness distribution paten in the marginal ice zone have been described ： sea ice thickness increased, but the diversity of floe ice thick-ness decreased from open water to fast ice zone distinctly.     

Fabric and crystal characteristics of Bohai and Arctic sea ice

1　ＩｎｔｒｏｄｕｃｔｉｏｎＢｏｈａｉｏｎｅ ｙｅａｒｉｃｅａｎｄＡｎｔａｒｃｔｉｃｏｎｅｈａｖｅｔｈｅｓｉｍｉｌａｒｓｕｒｆａｃｅ ｆｅａｔｕｒｅｓａｎｄｃｏｒｒｅ ｓｐｏｎｄｉｎｇｆａｂｒｉｃａｎｄｃｒｙｓｔａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓ (Ａｌｌｉｓｏｎ 1 997;Ｌｉｅｔａｌ.1 997;Ｑｉｎ 1 991 ) .ＤｕｒｉｎｇｔｈｅＣｈｉｎａＦｉｒｓｔＡｒｃｔｉｃＥｘｐｅｄｉｔｉｏｎ ,ｔｈｅｒｅｓｕｌｔｓｉｎｔｈｅｓｔｕｄｙｏｆｏｎｅ ｙｅａｒｉｃｅｆｒｏｍＢｏｈａｉａｎｄＡｎｔａｒｃｔｉｃｗｅｒｅｕｓｅｄｆｏ…     

Ice concentration assimilation in a regional ice-ocean cou- pled model and its application in sea ice forecasting

A reasonable initial state of ice concentration is essential for accurate short-term forecasts of sea ice using ice-ocean coupled models. In this study, sea ice concentration data are assimilated into an operational ice forecast system based on a com- bined optimal interpolation and nudging scheme. The scheme produces a modeled sea ice concentration at every time step, based on the difference between observational and forecast data and on the ratio of observational error to modeled error. The impact and the effectiveness of data assimilation are investigated. Significant improvements to predictions of sea ice extent were obtained through the assimilation of ice concentration, and minor improvements through the adjustment of the upper ocean properties. The assimilation of ice thickness data did not significantly improve predictions. Forecast experiments show that the forecast accuracy is higher in summer, and that the errors on five-day forecasts occur mainly around the marginal ice zone.     

The role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007

A model study is conducted to examine the role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007. The model generally agrees with the observations in showing considerable seasonal and interannual variability of the Pacific water inflow at Bering Strait in response to changes in atmospheric circulation. During summer 2007 anomalously strong southerly winds over the PaCific sector of the Arctic Ocean strengthen the ocean circulation and bring more Pacific water into the Arctic than the recent （2000-2006） average. The simulated summer （3 months ） 2007 mean Pacific water inflow at Bering Strait is 1.2 Sv, which is the highest in the past three decades of the simulation and is 20% higher than the recent average. Particularly, the Pacific water inflow in September 2007 is about 0.5 Sv or 50% above the 2000-2006 average. The strengthened warm Pacific water inflow carries an additional 1.0 x 1020 Joules of heat into the Arctic, enough to melt an additional 0.5 m of ice over the whole Chukchi Sea. In the model the extra summer oceanic heat brought in by the Pacific water mainly stays in the Chukchi and Beaufort region, contributing to the warming of surface waters in that region. The heat is in constant contact with the ice cover in the region in July through September. Thus the Pacific water plays a role in ice melting in the Chukchi and Beaufort region all summer long in 2007, likely contributing to up to O. 5 m per month additional ice melting in some area of that region.     

Measurements of sea ice thickness and its subice morphology analysis using ice-penetration radar in the Arctic Ocean

1　IntroductionSeaice ,asanimportantcomponentoftheArcticclimatesystem ,hasdrawnsignifi cantscientificinterest.Seaicethicknessanditsmorphologyhavedramaticimpactsono cean atmosphere iceinteractions(Wadhams 1 994;Barryetal.1 993 ;Dickson 1 999;PadhamsandNorman 2 0 0 0 ) ,whichdirectlyaffecttheexchangeprocessandspeedofheatandmassbetweentheoceanandtheatmosphere ,dominatethephysicalmechanicsfea turesofseaice ,andaffecttheseaicemovement&deformationaswellasicefreezing&meltingprocess(Hollandetal.1 99…     

Sea ice thickness and concentration in Arctic obtaining from remote sensing images

1　Introduction TheArcticOceanisoneoftheimportantcoldregionsontheearth,whichcanaffect globalclimateandoceancirculationseriously.Itsinteractionwiththeglobalclimatesystem isrepresentedbyseaice,whichisthemainfeatureonthesurfaceoftheArcticOcean(Aa gaardandCarmack1989).First,seaiceplaysapivotalroleintheheatandmassbalance onthesurfaceoftheArcticOcean.Seaicenotonlyobstructstheheatexchangebetweenat mosphereandocean,butalsoreflectsmostsolarradiationbacktotheatmospherebecause ofitshighalbedo(Gre…     

A coupled multi-category sea ice model and POM for Baffin Bay and the Labrador Sea

An overview of the seasonal variation of sea-ice cover in Baffin Bay and the Labrador Sea is given. A coupled ice-ocean model, CECOM, has been developed to study the seasonal variation and associated ice-ocean processes. The sea-ice component of the model is a multi-category ice model in which mean concentration and thickness are expressed in terms of a thickness distribution function. Ten categories of ice thickness are specified in the model. Sea ice is coupled dynamically and thermodynamically to the Princeton Ocean Model. Selected results from the model including the seasonal variation of sea ice in Baffin Bay, the North Water polynya and ice growth and melt over the Labrador Shelf are presented.     

THE DISCOVERED DEEP BURIED LAKE ICE IN SOURCE REGION OF THE HUANGHE RIVER

The 4.45 m-thick pure ice lens have been discovered firstly at depth from 19.81 -24.26 m in the bore No.6, which locates in north bank of the Ngoring Lake. In source region of the Huanghe (Yellow) River, 14C dating, X -ray diffraction, pollen analysis, micropalaeontology, chemical components, environmental isotope 2H, 3H, 18O and freezing point of the ice and water samples from the bore have been tested and microorganism in the ice have been also appraised with microscope. Combined with the research on geomorphy and Quaternary around the lake, the ice lens are determined as a kind of deep-buried lake ice, formed in 35,030-45,209 yr.B.P., and annual mean air temperature was about -10℃ during that time.