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平流层微量气体变化趋势及其化学过程的研究
Study on the Trends and Chemical Process of Trace Gases in Stratosphere
【作者】 施春华;
【导师】 陈月娟;
【作者基本信息】 中国科学技术大学 , 空间物理, 2006, 博士
【摘要】 平流层微量成分对地球生态环境和气候系统影响巨大,所以包括臭氧、NOx、HCl、H2O和CH4等在内的平流层微量气体的变化一直广受关注。本论文首先通过对HALOE、SAGE ⅡI和ECMWF/ERA-40资料的分析,研究了平流层微量气体的变化特征,分析了臭氧变化和其它微量成分的关系,以及臭氧变化和温度变化的关系。然后使用NCAR的包含化学、辐射、动力相互作用的两维模式(SOCRATTES)研究了平流层微量气体变化中动力输送和光化作用的相对重要性,以及地表人为排放有机氯在1990年的基础上增加30%后,对平流层臭氧和其它微量成分的影响。得到的主要结论如下: 第一,通过对HALOE资料的分析,给出了臭氧、NO、NO2、HCl、HF、H2O和CH4从1992年到2005年底的变化趋势,多数微量气体在1997年和1998年前后出现了不连续的变化,这与保护臭氧层的蒙特利尔协议的生效有关。臭氧在1998年以前缓慢减少,但趋势显著,1998年以后基本稳定并有所恢复。HCl和HF在1998年以前增加,1998年以后开始减少。NOx在1998年以前稍有增加,1998年以后基本稳定。水汽在1992年到1995年有增加的趋势,1996年到2000年基本稳定在较高的浓度,2000年以后水汽有逐步减小的趋势。甲烷的变化不是很显著,在平流层中上层1998年以前稍有减少的趋势,1998年以后略有增加或基本稳定,平流层下层正好相反。这些微量成分的周期特征,在低纬平流层,上层半年周期信号较强,中层准两年周期显著,下层季节变化加强。中高纬平流层以季节变化为主。 第二,本文通过对光化理论和HALOE、SAGE Ⅱ及ECMWF/ERA-40资料的分析,表明臭氧和温度变化在平流层上层存在反相关关系。而在平流层中层,臭氧和温度正相关。光化理论显示,理想光化平衡条件下,臭氧与ClOx,NOx和HOx反相关。 第三,模拟研究表明,平流层NOx、ClOx和HOx对臭氧的破坏作用都是重要的,相对来讲NOx起重要作用的高度在平流层中下层,ClOx和HOx起重要作用的高度在平流层中上层,但南极臭氧洞例外。7月,北半球高纬60°到极区的平流层中下层是臭氧的主要光化损耗区,这主要是该区域的NOx增加后光化
【Abstract】 Since the stratospheric trace gases play an important role in the ecological environment and climate system on the earth, more attentions are paid on the trends of stratospheric trace gases including ozone, nitrogen oxide, nitrogen dioxide, chlorine hydride, water vapor, and methane etc. Firstly, this study investigates the trends of stratospheric trace gases, the correlation between ozone and ozone-relevant trace gases, and the correlation between ozone and temperature by analyzing the data from HALOE, SAGE II and ECMWF/ERA-40. And then the simulations were carried out by using the NCAR interactive chemical, dynamical and radioactive two-dimensional (SOCRATES) model to investigate the contribution of dynamical transport and photochemical processes to the budgets of ozone and the other trace gases. Another simulation has been done to investigate the effects of the increase of Chloro-Fluoro-Carbon release on the stratospheric trace gases. The obtained results are below:Firstly, by analyzing the HALOE data, the trends of O3, NO, NO2, HCl, HF, H2O and CH4 since 1992 are obtained, most of the tracer evolutions are discontinuous between 1997 and 1998 due to the Montreal Protocol. Ozone mixing ratio decreased slightly in stratosphere before 1998, after 1998 ozone mixing ratio was relatively stable and began to increase. NOx, HF and HCl mixing ratio increased year by year before 1998, respectively. After 1998, NOx, HF and HCl mixing ratio was relatively stable and began to decrease. Water vapor increased from 1992 to 1995, kept high value from 1996 to 2000, and decreased since 2000. The variation of Methane is not significant. In the middle and upper stratosphere, methane decreased slightly before 1998, while after 1998 methane kept the value or increased a little. The changes of Methane in the lower stratosphere opposed to that in the upper stratosphere. The tracers in HALOE data reveals dominant modes of variability consisting of annual, semiannual, and quasi-biennial oscillations (QBO). At low latitude zone, the semiannual variations occur most in the upper stratosphere, the QBO variations occur most in the middle stratosphere and the annual variations occur most in the lower
【Key words】 stratosphere; trace gases; ozone; nitrogen oxide; nitrogen dioxide; chlorine hydride; water vapor; methane; temperature; dynamical transport; photochemical process; ozone hole; SOCRATES two-dimensional model;