Southern Hemispheric halogen budgets, mean age distributions, age spectra and interhemispheric difference using GhOST-MS observations during SOUTHTRAC

本提案的主要目的是在SOUTHTRAC运动期间进行卤化烃和SF6的观测。SF6是一种示踪剂，可用于推导平均穿越时间（平均年龄）。测量将使用HALO上的原位气相色谱仪GHOST-MS进行，该色谱仪已在之前的HALO任务中成功部署。测量结果将用于研究以下两个工作包，这两个工作包都将由博士生解决：主要问题：WP1：南半球的平均年龄和年龄谱？SH UTLS的平均年龄分布如何？它与北半球的分布是否不同？由此可以得出关于平流层-对流层交换的哪些结论？由对短寿命物质的观察得出的穿越时间分布是什么样的？这些年龄谱与模拟年龄谱相比如何？大脑半球之间是否存在差异？WP2：南半球氯和溴的收支两半球间短寿命物质的分布有何不同？这些分布与使用不同排放情景的模式计算的吻合程度如何？南半球UTLS对氯和溴的卤素预算是多少？它与北半球相比如何？这对臭氧消耗有什么影响？

TThe main purpose of this proposal is to perform observations of halogenated hydrocarbons and SF6 during the SOUTHTRAC campaign. SF6 is a tracer which can be used to derive mean transit times (mean age). The measurements will be performed with the in-situ gas chromatograph GHOST-MS on board HALO, which has been successfully deployed during previous HALO missions. The measurements will be used to investigate the following two work packages, which will both be addressed by a PhD student: main questions: WP1: mean age and age spectra of the Southern Hemisphere? What is the distribution of mean age in the SH UTLS? Is it different from the Northern Hemisphere distribution and which conclusions on stratosphere-troposphere-exchange can be drawn from this?What do transit time distributions derived from the observation of short-lived substances look like? How do these age spectra compare to modelled age spectra? Is there an interhemispheric difference?WP2: chlorine and bromine budget of the Southern HemisphereHow does the distribution of short lived substances differ between the two hemispheres? How well do the distributions agree with model calculations using different emission scenarios? What is the halogen budget of the Southern Hemisphere UTLS for both chlorine and bromine? How does it compare to the Northern Hemisphere? Which implications can this have for ozone depletion?