Using the recent compilation of the isotopic composition data of surface snow of Antarctic ice sheet, we proposed an improved interpolation method of δD, which utilizes geographical factors (i.e., latitude and altitude) as the primary predictors and incorporates inverse distance weighting (IDW) technique. The method was applied to a high-resolution digital elevation model (DEM) to produce a grid map of multi-year mean δD values with 1km spatial resolution for Antarctica. The mean absolute deviation between observed and estimated data in the map is about 5.4‰, and the standard deviation is 9‰. The resulting δD pattern resembles well known characteristics such as the depletion of the heavy isotopes with increasing latitude and distance from coast line, but also reveals the complex topographic effects.
This study investigates the regional distribution of marine aerosol originated species(Na+, Cl-, nss-SO42- and MSA) in the snow pits(or firn cores) collected along a transect between Zhongshan Station and the Grove Mountain area(450 km inland) on the eastern side of the Lambert Glacier Basin. Concentrations of Na+ and Cl- decrease exponentially with distance from the coast to 100 km inland(i.e., 1500 m a.s.l.). Statistical results demonstrate that distance from the coast inland and elevation affect the concentration of sea-salt originated ions in inland areas significantly. Increase of Cl-/Na+ ratio and higher variability in its standard deviation suggest that there are other sources of ions in addition to sea-salt in inland areas of the Antarctic continent. The concentrations of Na+ and Cl- from nine sampling sites in the Grove Mountain area are relatively higher than those from sites along CHINARE transect, although all sites are at similar distance inland. This phenomenon indicates that the barrier effect of the mountain may be the most important factor influencing ion deposition. In addition, nss-SO42- and MSA vary differently, with nss-SO42- decreasing with distance more significantly. This implies that sources and transporting pathways influence the deposition of the two sulfur compounds considerably, being supported by the spatial pattern of correlation coefficients between the nss-SO42- and MSA.
A database of Antarctic 10m firn temperature was constructed using available borehole temperature measurements with data quality control to extend knowledge of Antarctic climate.Slopes from a high-resolution digital elevation model and the main ice divide were used to delineate main drainage sectors across Antarctica.In each drainage sector,a quantitative relationship between temperature and latitude,longitude and altitude was established using available firn temperature data.Quantitative relationships incorporating other factors affecting Antarctic air temperature such as atmospheric circulation and small-scale topography were used to derive a 10-km resolution grid map of surface temperature.The resulting temperature patterns presented a reasonable depiction of both large and small-scale variations in Antarctic 10m firn temperature.This map is useful for many spatial variation studies,Antarctic ice sheet models,and comparison with satellite-derived temperature data and outputs of atmospheric general circulation models.
WANG YeTang1,3 & HOU ShuGui2,3 1 Shandong Marine Fisheries Research Institute,Yantai 264006,China
The topographic maps of 1:50,000 scales,aerial photographs taken in 1966,one Landsat image taken in 1999,and SRTM data from 2000 were used to quantify the losses in area and volume of the glaciers on the Su-lo Mountain,in the northeastern Tibetan Plateau,China in the past 30 years.The total glacier area decreased from 492.9km2 in 1966 to 458.2km2 in 1999.The volume loss of the studied glaciers reached 1.4 km3 from 1966 to 2000.This agrees with documented changes in other mountain glaciers of the whole Tibetan Plateau.
WANG YetangHOU ShuguiHONG SungminHUR Soon DoLIU Yaping
Stable isotopic composition in Antarctic snow and ice is commonly regarded as one of invaluable palaeoclimate proxies and plays a critically important role in reconstructing past climate change.In this paper we summarized the spatial distribution and the controlling factors of δD,δ18O,d-excess and 17O-excess in Antarctic snow and ice,and discussed their reliability and applicability as palaeoclimate proxies.Recent progress in the stable isotopic records from Antarctic deep ice cores was reviewed,and perspectives on bridging the current understanding gaps were suggested.
Bacterial abundance and diversity in snow of East Rongbuk, Laohugou and Halluogou glaciers on the Tibetan Plateau were investigated through epifluorescence microscope and denaturing gradient gel electrophoresis. Cell abundance ranged from 4.0 × 10^3 to 290.2 × 10^3 cells/mL. The phylogenetic trees placed the 16S rRNA sequences in four major groups： Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. Brevundimonas, Flavobacterium, Hymenobacter, Bacillus, Polaromonas, Rhodoferax and Streptomyces were widely distributed bacteria in glaciers from different cold regions. The remaining five genera of Hylemonella, Delftia, Zoogloea, Blastococcus and Rhodococcus were endemism, only recovered from our investigated glaciers. It is proposed that the three glaciers on the Tibetan Plateau provide a specific ecological niche for prolonging survival of diverse microbial lineages.
