A kinetic chemistry tagging technique and its application to modelling the stable isotopic composition of atmospheric trace gases
A kinetic chemistry tagging technique and its application to modelling the stable isotopic composition of atmospheric trace gases
复制标题
动力学化学标记技术及其在大气痕量气体稳定同位素组成建模中的应用
DOI：
10.5194/gmd-3-337-2010
复制
发表时间：
2010
影响因子：
5.1
通讯作者：
C. Brenninkmeijer
中科院分区：
文献类型：
--
作者：
S. Gromov;P. Jöckel;R. Sander;C. Brenninkmeijer
抽象的。在许多情况下，同位素组成具有关于大气痕量气体的来源、化学变化和汇的独特信息。对越来越多的同位素分析的解释和使用至关重要的是适当的建模。然而，同位素信息在化学气候模型中的准确实施是一个挑战，并且经常使用简化的研究限制了其适用性。在这里，我们实现了一个彻底的同位素扩展MECCA，一个全面的动力学化学子模型。为此，我们设计了一个通用的标记技术的动力学化学机制实现的子子模型MECCA-TAG。该技术是诊断和数值效率，并支持动力学化学方案的各个方面的调查。我们专注于稳定同位素组成的建模应用。MECCA-TAG的结果与参考子子模型MECCA-DBL进行了比较，该模型隐含了完整的细节，但计算量很大，因此在实际应用中是次优的。此外，我们通过模拟CO和其他痕量气体的多同位素组成的CAABA/MECCA盒模型中的精细的碳和氧同位素机制进行评估。该机制逼真地模拟了关键物种的氧同位素组成，以及碳同位素特征转移。该模型充分再现了CO的同位素化学特征，同时考虑到建模域的限制。特别是，质量独立分馏（MIF）CO组合物由于臭氧与不饱和烃（源效应）的反应与其固有的MIF富集诱导的去除反应通过OH氧化进行评估。在Δ 17 O（CO）中，模拟的臭氧源效应可达+1‰。我们采用的多功能建模框架（模块化地球子模型系统，MESSy）开辟了在三维大气化学环流模型EMAC中实施新的详细同位素化学处理的途径。因此，我们还提出了估计的计算增益所获得的发达国家的优化。
Abstract. Isotope composition, in many cases, holds unique information on the sources, chemical modification and sinks of atmospheric trace gases. Vital to the interpretation and use of an increasing number of isotope analyses is appropriate modelling. However, the exact implementation of isotopic information in chemistry-climate models is a challenge, and often studies use simplifications which limit their applicability. Here we implement a thorough isotopic extension in MECCA, a comprehensive kinetic chemistry sub-model. To this end, we devise a generic tagging technique for the kinetic chemistry mechanisms implemented as the sub-submodel MECCA-TAG. The technique is diagnostic and numerically efficient and supports the investigation of various aspects of kinetic chemistry schemes. We focus specifically on the application to the modelling of stable isotopic composition. The results of MECCA-TAG are evaluated against the reference sub-submodel MECCA-DBL, which is implicitly full-detailed, but computationally expensive and thus sub-optimal in practical applications. Furthermore, we evaluate the elaborate carbon and oxygen isotopic mechanism by simulating the multi-isotope composition of CO and other trace gases in the CAABA/MECCA box-model. The mechanism realistically simulates the oxygen isotope composition of key species, as well as the carbon isotope signature transfer. The model adequately reproduces the isotope chemistry features for CO, taking into account the limits of the modelling domain. In particular, the mass-independently fractionated (MIF) composition of CO due to reactions of ozone with unsaturated hydrocarbons (a source effect) versus its intrinsic MIF enrichment induced in the removal reaction via oxidation by OH is assessed. The simulated ozone source effect was up to +1‰ in Δ17O(CO). The versatile modelling framework we employ (the Modular Earth Submodel System, MESSy) opens the way for implementation of the novel detailed isotopic chemistry treatment in the three-dimensional atmospheric-chemistry general circulation model EMAC. We therefore also present estimates of the computational gain obtained by the developed optimisations.