1844 AD以来珠穆朗玛峰地区大气环境变化高分辨率冰芯记录

A High-Resolution Ice Core Record from Mount Qomolangma since 1844 AD

根据珠穆朗玛峰东侧东绒布冰川海拔6450 m处长度为80.36 m的冰芯1886个样品的δ18O与主要离子浓度资料,研究了1844 AD以来珠穆朗玛峰地区大气环境在季节及年际尺度上的变化特征.结果表明:δ18O与Na+、K+和Cl-相关不明显,与Ca2+、Mg2+、SO42-、NO3-和NH4+具有较强的相关性.据相关分析及因子分析的结果,可以把8种主要离子分成5组来研究,它们主要表现为:海盐离子Na+可反映印度夏季风强弱变化;K+和Cl-在一定程度上可以反映印度等南亚地区生物质燃烧量的变化;陆源Ca2+和Mg2+离子表现为春季的峰值和夏季的低值,冬春季高浓度的Ca2+和Mg2+可能主要来自南亚的塔尔沙漠,以及西亚的干燥少雨的高原地区,或更遥远的北非撒哈拉沙漠,同时,青藏高原本身也可能是一个重要的沙尘源区;NO3-和SO42-离子浓度表现出高频的季节变化特征,存在春季的峰值和夏季的低值,20世纪70年代初期至90年代初期,NO3-和SO42-离子浓度一直维持在较高的水平;NH4+浓度在20世纪40年代以来的大幅度上升可能是世界大战后,社会趋于稳定,南亚地区农业迅速发展而大量使用化学肥料的结果.

The seasonal and annual variations of δ^18O values and concentrations of major ions （Ca^2＋, Mg^2＋, Na^＋, K^＋, NH4^＋ SO4^2-, NO3^- and Cl^-） of an 80.36 m ice core recovered from the East Rongbuk Glacier are studied in order to understand the characteristics of atmospheric environment in the Mount Qomolangma region. Resuits of the correlation analyses and factor analysis show that the δ^18O values are positively correlated with Ca^2＋, Mg^2＋, NH4^＋, SO4^2- and NO3^- concentrations, but are not relevant to Na^＋ , K^＋ and Cl^- concentrations. The variation tendencies of Ca^2＋ and Mg^2＋ concentration, of which the main source is dust in the atmosphere, are represented by Factor 1. High concentrations of dust species are mainly due to the import of spring dust storms from Thar Desert in Southwest Asia. The variation tendencies of sea salt ion concentrations are in- dicated by Factor 2. The concentrations of the sea salt ions are correlated with the Indian summer monsoon rainfall. Thus it is possible to recover the history of the Indian summer monsoon by using sea salt ions. The high concentrations of SO4^2-, NO3^- from the 1970s to the 1990s were caused by the development of agriculture and industry of Indian. It is believed that the unique sharp increase of ammonium concentrations during the second half of the 20th century was due to the change in the regional agriculture activities.