Nonlinear Response of Stratospheric Ozone Column to Chlorine Injections
Nonlinear Response of Stratospheric Ozone Column to Chlorine Injections
复制标题
平流层臭氧柱对氯注入的非线性响应
DOI：
10.1029/jc088ic06p03647
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发表时间：
1983
影响因子：
--
通讯作者：
S. Liu
中科院分区：
文献类型：
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作者：
R. Cicerone;S. Walters;S. Liu
通过一个相当完整和最新的平流层光化学模型，我们发现计算的平流层臭氧层对氯注入的响应是高度非线性的。模型计算假定背景无机(或奇数)氯Clx是由CH3Cl和CCl4引起的。通过改变CCl2F2和CCl3F的输入通量，将额外的CLX添加到平流层。平流层臭氧柱对添加Clx的敏感度ΔO3/ΔClx相对较小，对于Clx≲为3 ppb或ΔClx≲为2 ppb；如果硝酸氯的形成迅速进行，则在有限的Clx范围内，使用Clx可能会略微增加臭氧。这可能会对臭氧总量趋势评估产生重要影响。当CLX增加到3 ppb以上时，平流层臭氧柱随着CLX的增加而迅速减少。这明显偏离了过去几年计算的线性，这在很大程度上是由于目前公认的OH与HNO3、HNO4、HO2和H2O2的反应速度更快。如果由于CCl2F2、CCl3F和CH3CCl3的持续使用，平流层Clx增加到约9 ppb，则计算出平流层臭氧柱损耗为6.7-9.0%。讨论了这些计算中的主要不确定因素，包括硝酸氯的生成速度、其光解产物以及目前CLX的混合比。还给出了由于N2O浓度增加而导致臭氧减少的计算结果。
With a reasonably complete and up-to-date photochemical model of the stratosphere, we find that the calculated stratospheric ozone-column response to chlorine injections is highly nonlinear. The model calculations assume that the background inorganic (or odd) chlorine, ClX, is due to CH3Cl and CCl4. Additional ClX is added to the stratosphere by varying input fluxes of CCl2F2 and CCl3F. The sensitivity, ΔO3/ΔClX, of the stratospheric O3 column to added ClX is relatively small for ClX ≲3 ppb or ΔClX ≲2 ppb; slight ozone increases with ClX are possible over a limited range of ClX if the formation of chlorine nitrate proceeds rapidly. This may have important implications for total ozone-column trend assessment. As ClX increases beyond 3 ppb, the stratospheric O3 column decreases with ClX increasingly rapidly. This marked departure from the linearity calculated in past years is largely due to presently accepted faster rates of reaction of OH with HNO3, HNO4, HO2, and H2O2. If stratospheric ClX increases to about 9 ppb due to continued usage of CCl2F2, CCl3F, and CH3CCl3, the stratospheric O3 column depletion is calculated to be 6.7–9.0%. Principal uncertainties in these calculations, including the rate of formation of chlorine nitrate, the products of its photolysis, and the present day mixing ratio of ClX are discussed. Calculated ozone decreases due to increased N2O concentrations are also presented.