东南极冰盖中山站-Dome A断面表层雪中SO_4^(2–)和MSA的空间分布特征

SPATIAL DISTRIBUTION CHARACTERISTICS OF SO_4^(2-) AND MSA IN SURFACE SNOW ALONG THE TRAVERSE ROUTE FROM ZHONGSHAN STATION TO DOME A, EAST ANTARCTICA

中山站-Dome A断面考察是国际横穿南极科学考察计划(ITASE)的核心考察路线之一,具有重要的科学意义,在国内外产生了广泛影响。中国第31次南极科学考察内陆冰盖考察期间,采集了中山站-Dome A断面上约10 km间隔的表层雪样品,通过离子色谱实验分析,得出了断面上含硫化合物(SO_4^(2-)与MSA)的含量。在整个断面上,nssSO_4^(2-)和MSA含量表现出微弱的递减变化趋势,呈现出区域性变化趋势。在内陆高原区域(Dome A区域),nssSO_4^(2-)与MSA存在较好的线性关系([MSA]=0.1158×[nssSO_4^(2-)]–1.1497,r^2=0.75)。MSA/nssSO_4^(2-)比值在断面上的变化范围为0.04—0.47,均值为0.14,比值表现为沿海区域高于内陆区域,与低温条件下MSA/nssSO_4^(2-)比值大相矛盾,原因是由于源区的不同或风场而造成的。通过对断面上含硫化合物的研究,为进一步利用冰芯SO_4^(2-)与MSA记录研究过去气候环境提供了科学依据。

The traverse route from Zhongshan Station to Dome A in East Antarctica is one of the main expedition routes of the International Trans-Antarctic Scientific Expedition （ITASE）, which has considerable global scientific significance. Following the inland ice sheet scientific expedition of the 31st CHINARE, surface snow samples collected at 10-km intervals along this route were analyzed using ion chromatography and content concentrations of sulfur compounds （SO4^2- and MSA） were obtained. The nssSO4^2- and MSA contents along the traverse route presented no obvious overall trend of decrease in spatial variation with increasing distance from the coast, but regional trends were detected. Significant correlation was found between nssSO4^2- and MSA in the inland plateau area of Dome A, with a linear relation of [MSA] = 0.115 8 × [nssSO4^2-] - 1.149 7 （r^2= 0.75）. The MSA/nssSO4^2- ratio along the traverse route was also calculated （range： 0.04-0.47; mean： 0.14）, which revealed that the ratio in coastal areas was higher than inland areas. Different sources or the wind field streamlines of the transect might be the main reasons for the finding of inconsistently higher MSA/nssSO4^2- ratios at lower temperatures. Further research on the sulfur compounds along the transect in this study would be enhanced by consideration of the climatic environment based on ice core records of nssSO4^2- and MSA.