中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
羰基硫及其前体物在大气和自然水体中的分布

文献类型:学位论文

作者徐竹
学位类别博士
答辩日期2010
授予单位中国科学院研究生院
授予地点北京
导师牟玉静 ; 张晓山
关键词羰基硫 前体物 自然水体 大气 冰芯
中文摘要
      大气中羰基硫(COS)对太阳辐射平衡和全球气候变化具有重要的间接影响,其源和汇的认识成为当今环境科学的热点研究领域之一。然而,目前对于其源和汇的认识还存在很大的不确定性,特别是近年来发现植被吸收大气COS强度为过去估算值的五倍以上,造成大气中COS源和汇收支的极大不平衡,即大气中COS存在人们尚未认知的重要来源或有些来源被大大低估。为此,本文研究了降水、自然水体、大气及冰芯中的COS及其前体物的浓度分布。 水样品中COS前体物采用紫外光照-吹扫捕集-GC-FPD测定。大气中COS前体物的采样和分析方法为:蒸馏水富集-紫外光照-吹扫捕集-GC-FPD测定。 测定了北京市全年降水中的COS初始溶解浓度和COS前体物浓度,发现降水中都存在着COS过饱和现象,COS前体物浓度大约是COS初始溶解浓度的3倍。COS初始溶解浓度与COS前体物浓度存在显著正相关,表明降水中过饱和的COS来自于COS前体物。降水中COS的前体物浓度随着降水的持续而逐渐下降,并且降水中COS的前体物浓度与降水量存在显著负相关,推测降水中的COS前体物来自于降水对大气中COS前体物的洗脱。 研究了全国部分地区自然水体中COS的初始溶解浓度和COS前体物浓度分布。同样发现自然水体中都存在着COS过饱和现象及高浓度的COS前体物。并且通过比较降水和自然水体中COS初始溶解浓度和COS前体物的浓度,发现降水是各自然水体中COS及其前体物的重要源。根据海水中COS的初始溶解浓度及其前体物的浓度与太阳辐射关系,认识到海水中COS主要来源于其前体物的光化学反应。 测定了北京市全年大气中COS前体物的浓度,发现其浓度存在显著的日变化和季节变化。降雨过程中COS 前体物浓度显著降低很好验证了降水中COS 前体物主要来自对大气中COS 前体物洗脱的推测。 研究了纳木那尼冰芯和达索普冰芯中COS的初始溶解浓度。率先测定了纳木那尼冰芯冰芯中COS前体物的浓度。发现冰芯中COS及其前体物的浓度随着样品深度的增加而降低,说明人类活动对于降水中COS及其前体物有着重要的影响。
英文摘要      Carbonyl sulfide (COS) in the atmosphere plays an important role on the earth’s radiation budget as well as the global climate change. Understanding of COS sources and sinks strengths become one of hot research fields of Environmental Science. Now, the estimation of the sources and sinks contains considerable uncertainties. Recent investigations revealed that COS uptake by terrestrial vegetation has been underestimated for 5 times, leading to a great imbalance between sources and sinks of COS in budgets. There are important unknown sources or some sources to be greatly underestimated. So, in this dissertation, the concentrations of the initial dissolved COS and COS precursor(s) from precipitations, natural waters, atmospheres and ice cores were investigated. The sampling method of distilled water was used as the collection of COS precursor(s) in atmosphere. The concentration of COS precursor(s) in water sample and in air sample was firstly radiated by UV, and then measured by flush-trapping technique, finally analyzed by GC-FPD. The initial dissolved COS and COS precursor(s) in precipitations from Beijing during the whole year were investigated. All investigated precipitation samples were found to be supersaturated with COS. And the concentration of COS precursor(s) in precipitation was about 2 times higher than the initial COS. The significant positive correlation between the concentration of the initial COS and COS precursor(s) indicated that the supersaturated COS could be produced from COS precursor(s) in precipitations. The decrease in the concentration of COS precursor(s) during a sequential rain event, and the high negative correlation between rainfall intensity and the concentration of COS precursor(s), also revealed that precipitation might scavenge COS precursor(s) in the atmosphere. The initial dissolved COS and COS precursor(s) in natural waters from partly provinces of China were investigated in winter and in summer. All investigated natural waters samples were also found to be supersaturated with COS, and contained high amount of COS precursor(s). Comparison the concentration of the initial COS and COS precursor(s) in precipitations and in natural waters, this phenomenon suggested that precipitation could be considered as the source of COS and COS precursor(s) in natural waters. Significant amount of COS precursor(s) in the atmosphere from Beijing during the whole year was first observed. There were exited the obvious diurnal and seasonal variations of COS precursor(s). The reduction of COS precursor(s) concentrations during the raining day proved that COS precursor(s) in precipitation stemmed from atmosphere. The concentrations of initial dissolved COS in Namunani ice core and Dasuopu ice core were determined. And it is firstly researched the COS precursor(s) concentrations in Namunani ice core. The concentrations of initial COS and COS precursor(s) decreased with the depth of ice cores, indicating that human activity made significant effect on COS and COS precursor(s).
源URL[http://ir.rcees.ac.cn/handle/311016/35070]  
专题生态环境研究中心_大气环境科学实验室
推荐引用方式
GB/T 7714
徐竹. 羰基硫及其前体物在大气和自然水体中的分布[D]. 北京. 中国科学院研究生院. 2010.

入库方式: OAI收割

来源:生态环境研究中心

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