Transport and composition of the southern hemisphere UTLS (SOUTHTRAC)

南半球 UTLS (SOUTHTRAC) 的运输和组成

• 批准号: 423219384
• 负责人: Professor Dr. Andreas Engel
• 金额: --
• 依托单位: Institut für Physik der Atmosphäre
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/423219384?language=en
• 关键词: Transport; composition; southern; hemisphere; UTLS

Changes in the distribution of trace gases, like water vapor and ozone in the upper troposphere and lower stratosphere (UTLS) strongly impact radiative forcing and the Earth's climate and surface temperatures, and are of key importance for understanding climate change. Due to the high sensitivity of atmospheric radiative forcing to changes in greenhouse gases in the cold tropopause region even small variations e. g. in water vapour in the lower stratosphere are an important source of the decadal variability of the surface temperature. There is also large uncertainty in future changes of ozone and water vapour in the UTLS, limiting the ability to predict the radiative forcing due to stratospheric ozone recovery and related processes during the 21st century: Several studies  have shown that different chemistry climate models do not even agree on the sign of radiative forcing due to ozone recovery because of large uncertainties in modelled composition particularly ozone and water vapour changes in the vicinity of the tropopause. Due to different wave focing and strong differences in the polar vortices of both hemispheres, significant differences between transport and composition of the UTLS between the Southern and Northern Hemisphere are expected. Despite the importance of the global UTLS dedicated field deployments studying transport processes and structure of the southern UTLS have not yet been performed. Previous field campaigns focused on Antarctic ozone depletion and vortex processes or the tropics or tropospheric composition. In addition, the winter southern hemisphere affects the global stratospheric circulation since the Andes constitute a global hot spot for gravity wave activity. The propagation of these waves and their impact are not yet fully understood. Therefore, we propose a HALO campaign, which addresses the following open key aspects regarding the processes affecting the composition of the southern UTLS region: (1) Exchange processes at the southern hemisphere tropopause (2) Gravity waves in the southern hemisphere (3) Influence of biomass burning on the southern hemisphere UTLS (4) Impact of the Antarctic vortex on the UTLS

对流层上部和平流层下部（UTLS）中的水蒸气和臭氧等痕量气体分布的变化强烈影响辐射强迫以及地球的气候和地表温度，对于理解气候变化至关重要。由于对流层顶冷区大气辐射强迫对温室气体变化的敏感性很高，即使是很小的变化，G.平流层低层水汽中的大气环流是地面温度年代际变率的一个重要来源。UTLS中臭氧和水蒸气的未来变化也存在很大的不确定性，这限制了预测世纪平流层臭氧恢复和相关过程造成的辐射强迫的能力：几项研究表明，由于模拟的成分特别是臭氧和水的成分存在很大的不确定性，不同的化学气候模式甚至在臭氧恢复引起的辐射强迫的迹象上都不一致对流层顶附近的水汽变化。由于南北半球的波聚焦和极涡的强烈差异，预计南半球和北方半球之间UTLS的输送和组成之间存在显着差异。尽管全球UTLS的重要性，研究南部UTLS的运输过程和结构的专门领域的部署尚未执行。以往的实地活动侧重于南极臭氧消耗和涡旋过程或热带或对流层的构成。此外，由于安第斯山脉构成全球重力波活动的热点，冬季南半球影响全球平流层环流。这些波的传播及其影响尚未完全了解。因此，我们提出了一个HALO活动，它解决了以下关于影响南UTLS区域组成的过程的开放关键方面：（1）南半球对流层顶的交换过程（2）南半球的重力波（3）生物质燃烧对南半球UTLS的影响（4）南极涡旋对UTLS的影响