南极洲Nelson冰帽排钻冰芯内的火山灰与冰川物质平衡

对采自南极洲南设得兰群岛Nelson冰帽一条断面上三支排钻冰芯内火山灰碎屑物成分进行了研究。根据1967—1970年期间欺骗岛(Deception Island)火山喷发物主要成分资料分析,认为这三层火山灰应属1970年欺骗岛火山喷发后的沉积物。据此可知,过去20年中,Nelson冰帽顶部GW处近年来的平均积累速率为1200g·cm~(-2)·a(-1)。冰帽中部N30处的平均净积累量为700g·cm~(-2)·a(-1),边缘N50处则仅为6g·cm(-2)·a~(-1)。以此次火山灰为标记推知,Nelson冰帽东部的年净积累量高于北部。     

THE HISTORICAL CLIMATIC RECORDS IN ICE CORES FROM THE SURFACE LAYER OF WILKES LAND, ANTARCTICA

The information preserved in the surface layer of the Antarctic ice sheet is so abundant and detailed that in the areas with a high accumulation rate the annual climatic changes in the past can be distinguished. After conducting an investigation into the stratigraphical features of ice cores from two typical shallow boreholes in the Wilkes Land, one inland and another near the margin, analyzing δ(~18)O and the gross β radioactivity in the cores, as well as anslyzing the power spectra of δ~(18)O, the authors present some important assessments on the climatic information in the past several decades therein such as the annual mean temperature and precipitation, and suggest that there is a period of 11 years with which the climate changes cyclically in East Antactica. Such a studying method will be of value in both theory and practice to the inland Antarctica, where direct meteorological observation is deficient.     

东南极洲Wilkes Land地区冰盖浅表层内的历史气候记录

本文通过对东南极洲Wilkes Land内陆和边缘两支有代表性浅岩芯的雪层剖面特征研究、δ~(18)O和β活化度总量分析以及功率谱分析,发掘出浅岩芯内提供的本地逐年平均气温、逐年降水量和东南极洲存在一个11a的气候冷暖变化周期等主要气候信息。