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Subject: 地理学::自然地理学
Title: 喜马拉雅山中段达索普冰芯记录与现代气候环境变化研究
Author: 王朋岭
Issued Date: 2007-12-28
Supervisor: 姚檀栋
Major: 自然地理学
Degree Grantor: 中国科学院研究生院
Place of Degree Grantor: 北京
Degree Level: 博士
Call Number: B000003
Department: 图书馆
Abstract: 本文选择喜马拉雅山中段希夏邦马峰达索普高海拔冰川区作为研究区域,以高分辨率的雪坑和冰芯记录为研究对象,结合气象观测资料和NCAR/NCEP再分析资料,在前人研究成果的基础上,在不同时间尺度下研究该气候变化敏感地区的现代气候环境变化及其可能机制,主要得出如下结论:(1)在季节时间尺度下,达索普雪坑剖面氧同位素比值和化学记录的季节变化及夏季风季节不同层位间的变化,是局地气象条件和大尺度大气环流形式综合作用的产物;达索普雪坑所记录的夏季风季节不同层位间氧同位素比值和离子负荷的差异,是降水气团源地和南亚季风活动季内振荡的反映。(2)达索普16m粒雪芯记录研究表明,20世纪90年代以来,达索普高海拔地区雪冰化学组成主要受陆源组分和人类污染源组分的影响,而海盐组分贡献率相对较小;离子年沉积通量与粒雪芯年积累量的线性回归分析,揭示不同离子物质在沉降模式上存在的差异;区域现代环境事件(1999-2001中亚、西南亚持续干旱)在达索普粒雪芯记录中得到明显的反映;陆源Ca2+年沉积通量与区域降水率的相关场研究表明达索普粒雪芯记录中陆源组分的可能远距离物质源区主要为中亚及西南亚干旱区、印度西北部的塔尔沙漠,或更遥远的北非撒哈拉沙漠,同时局地裸露基岩及冰川末端的冰碛区同样可能是陆源组分的重要物源。(3)在百年时间尺度下,更新和延续达索普地区原有的冰芯记录,建立1900年以来达索普冰芯δ18O记录的时间序列。冰芯δ18O记录与邻近气象台站温度变化的一致性,说明在年代际时间尺度上冰芯δ18O记录可以反映区域70年代以来的气候变暖趋势。1900年以来,达索普冰芯δ18O记录与全球气温变化表现出显著的相关性,δ18O记录与全球SST的空间相关分析表明,位于青藏高原南部的达索普冰芯δ18O记录在几十年或更长时间尺度上反映其水汽源区即赤道印度洋面的温度变化,并对其可能的机制给出解释。
English Abstract: In this paper, the author chose the Dasuopu glacier region in the north slope of Xixiabangma Peak, middle Himalayas, as the research area, take the high-resolution snowpit and ice core record as the study object, integrating the observation data from meteorological station and NCAR/NCEP reanalysis data, under the foundation of previous studies, research the modern climate and environment changes, possible mechanism, in this sensitive area, from different time-scales. And the following conclusions can be achieved: (1) On the seasonal scale, the difference in stable oxygen isotopic ratio and chemical constitutes recoded by high-resolution snowpit samples between seasonal layers and intraseasonal layers, are the synthetical results from the local meteorological conditions and large-scale atmospheric circulation situations. The difference in the stable oxygen ratio and ionic burdens between different summer monsoon layers in Dasuopu snowpit, are the reflection of different vapour sources and intraseasonal oscillation of the South Asian Monsoon. (2) Studies on the 16m Dasuopu firn core record, indicate that the glaciochemical constitutes are mainly originated from the crustal and anthropogenic sources, while the sea-salt contribution was minor, in high-elevation Dasuopu Glacier area, since the 1990s. Linear regression analysis indicated that most of the variance in annual ionic fluxes can be explained by a linear dependence on snow accumulation rate, furthermore, the anthropogenic airborne aerosols mostly in accumulation mode, which were preserved in snow on the glacier surface mainly by wet deposition, while the crustal source species predominantly existed in coarse mineral dust particles, with dry deposition as major deposition process. The present regional environment event (1999-2001 Central and Southwest Asia Extreme Drought) was recorded in Dasuopu Glacier. Correlation coefficient fields relating annual ionic flux of terrestrial source Ca2+ and regional precipitation rate (Nov-Apr) from 1991 to 2005, make sure that the potential distant source area of the terrestrial constitutes in Dasuopu firn core, mainly distribute in the Central and Southwest arid area, the Thar Desert in northwest India, or even remote the Sahara Desert in North Africa; meanwhile, the local exposed rock of the glacier basin as well as moraine deposits in the downstream of glacier, could be an important contributing factor for the terrestrial constitutes. (3) On the century time-scale, updating the previous Dasuopu ice core record, establish the stable oxygen isotope record time series since the year of 1900. Confirming previous studies, the Dasuopu stable oxygen isotope record show great accordancy with the air temperature record from the neighbouring meteorological station, prove that the stable oxygen isotope record may reflect the regional warming trend since the 1970s. While the Dasuopu stable oxygen isotope ratio record show high correlation with the global temperature anomalies since 1900, and correlation coefficient field relating Dasuopu stable oxygen isotope ratio record and global sea surface temperature (Jun-Sep) time series, indicate that the significant positive correlation area locate in the tropical Indian Ocean area, the central area of Somali low-troposphere jet. These validate that the Dasuopu stable oxygen isotope ratio record could reflect the temperature change of its vapor source, namely the equatorial Indian Ocean area, and the author offer the potential explained mechanism.
Language: 中文
Content Type: 学位论文
Appears in Collections:图书馆_学位论文

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