The Spacial Distribution Features Of Chemical Compositions In Surface Snow Along The Traverse Route From Zhongshan Station To Dome A,East

The scientific expedition conducted independently by Chinese National Antarctic Research Expedition(CHINARE) along the traverse route from Zhongshan Station to Dome A, East Antarctica is one of the core expedition routes of the International Trans-Antarctic Scientific Expedition(ITASE). The traverse route from Zhongshan Station to Dome A, along the way through eastern side upstream of Lambert glacier, Gamburtsev subglacial mountains and the Dome A area which are the hot spots of Antarctic researches, has an important meaning of cryospheric and polar processes, ice cores and climate-environment scientific research, with a broad influence both at home and abroad. Chinese have conducted a continuous transect research tasks since2008, and many important and precious samples of surface snow, snow pits and the shallow ice cores were collected, as well as the scientific research data and climate meteorological data obtained along the transect from Zhongshan Station to Dome A, providing the service of data support and scientific basis for the subsequent further research work of deep ice cores.During the inland ice sheet scientific expedition of the CHINARE 31 th, wegot the surface snow samples every 10 km along the traverse route from Zhongshan station to Dome A, and obtained the concentration contents of sea-salt ions(Cl-, Na+, Mg2+), nitrate ions(NO3-) and sulfur compounds(SO42-and MSA) along the transect through the ion chromatography experimental analysis. The ion concentration levels were following the sequence as NO3- >SO42- > Cl- > Na+ > MSA > Mg2+. Significant positive correlation were found among the soluble sea-salt ions(Na+,Mg2+and Cl- with each other),with a correlation coefficient greater than 0.92(p≤0.01, n=116). Strong linear relationship was showed between Na+and Cl-contents and with a linear relation of [Cl-]=2.01 [Na+] + 16.60(R2=0.91, n=116).The three main sea-salt ions from same sources possessed a concurrent spatial variation tendency, and presented a negative correlations and the characteristic of exponential declining trend with increasing distance from the coast or increasing altitude. The NO3-concentrations showed positive correlations with distance from the coast or altitude, but negative correlations with temperature and annual accumulation along the traverse route from Zhongshan Station to Dome A.The nss SO42- contents dominate the major components of SO42- contents and accounting for about 95.0% of which in surface snow on the transect.The nss SO42- and MSA contents along the traverse route from Zhongshan station to Dome A are presented as not obvious decreasing characteristics of the overallspatial variation tendency with increasing distance from the coast, but regional trends are shown respectively. There shows a significant correlation of nss SO42-and MSA in the inland plateau of Dome A area and with a linear relation of[MSA] = 0.1158 × [nss SO42-]- 1.1497(R2=0.75). The MSA/nss SO42- ratios along the traverse route are also calculated, and the range is from 0.04 to 0.47,mean value is 0.14, the ratios of coastal areas is higher than the inland areas, different sources or the wind field streamlines of the transect may be the main reasons of the inconsistent viewpoint of higher MSA/nss SO42-ratios at lower temperature. Through the research of sulfur compounds along the transection in this study, filling the blank in the research of sulfur compounds along the transection, and the scientific research basis of climate environment would be provided by using the further study records of ice core nss SO42- and MSA.The transection from Zhongshan Station to Dome A is known as an ideal study area on water stable isotopic compositions of surface snow. Spatial distributions and impact factors studied about water stable isotope in surface snow along the transect have important significance in discussing the material sources and climatic environment changes of East Antarctic Ice Sheet. Therefore,the spacial distribution relations between δ18O, δD and different environmental factors are synthetically discussed based on linear regression analysis andcorrelation analysis. The results indicate that significant correlations are existed between δ18O and δD and with a linear relation of δD =7.4836 δ18O- 18.547(R2= 0.995,n=116). The δ18O and δD show strong significant negative correlations with distance from the coast, altitude and latitude, and both the two indexes show decreasing tendency with increasing elevation—the most important one of geographical factors. Moreover, there expressed significant linear relationships between δ18O and δD in surface snow and temperature, and the slopes of δ18O-T and δD-T are 0.96‰/℃ and 7.08‰/℃ respectively. Great differences of δ18O-T slopes are shown in different regions along the transect, different moisture sources and isotope fractionation under the conditions of moisture supersaturation in low temperature are the main reasons for causing the great differences, which can also serve as the reasons discuss and analyse for δ-T differences in different regions in Antarctica ice sheet.