Bromine and Chlorine budget in the Asian Monsoon outflow during PHILEAS

在本提案中，我们申请资金，以参与PHILEAS（探测亚洲夏季风高纬度空气输出）活动，使用GhOST仪器的HALO飞机。GhOST是一种双通道GC和GC/MS系统，为法兰克福大学的HALO操作而开发和构建。PHILEAS活动的中心问题是调查亚洲季风反气旋（AMA）的外流及其对混合到平流层低层的气团的影响。 美因茨大学（Peter Hoor教授）在PHILEAS活动的协调建议中概述了该活动的科学背景和成本。在PHILEAS期间，HALO将在第一阶段从Oberpfaffenhofen调查背景UTLS（对流层上部/平流层下部）和地中海上空季风环流的直接向西向外流。在第二阶段，HALO将以阿拉斯加为基地，探测季风区向东流出的空气。由于罗斯比波活动，阿拉斯加的活动基地很有可能观察到太平洋平流层下部AMA释放的气团。利用HALO上的GhOST仪器进行的测量将提供关于各种示踪剂的信息，这些示踪剂具有不同的寿命和不同的源/汇特性。测量的重点是卤化微量气体，此外SF6作为平均年龄示踪剂。根据设置，GhOST MS通道的重点是氯或溴族。在该提案中，计划进行测量，并将观测结果用于与PHILEAS有关的三个不同的研究问题：（一）AMA中的溴预算是多少，这如何影响平流层下部？(ii)AMA和AMA空气中的氯预算是多少？(iii)是否存在人为污染（例如使用CH 2Cl 2或HCFC-22）或生物质燃烧（CH 3Cl）的影响，例如可能与北方火灾有关。除了这些直接目标外，还计划进一步利用这些数据，通过与由DFG CRC 301（TPChange）内我们小组资助的IAGOS-加勒比测量相结合，研究对流层顶区域卤化碳的全球分布。此外，这些数据将提供给DFG资助的项目QUANTITEE，并在该项目中加以利用，以调查渡越时间分布。

In this proposal we apply for funding to participate in the PHILEAS (Probing High Latitude Export of air from the Asian Summer Monsoon) campaign with the HALO aircraft using the GhOST instrument. GhOST is a two-channel GC and GC/MS system, developed and build for operation on HALO at the University Frankfurt. The central question of the PHILEAS campaign is the investigation of the of the outflow of the Asian Monsoon Anticyclone (AMA) and its influence on the air masses mixed into the lower stratosphere. The scientific background and the costs of the campaign have been outlined in the co-ordination proposal to the PHILEAS campaign by the University Mainz (Prof. Dr. Peter Hoor). During PHILEAS, HALO will investigate the background UTLS (upper troposphere/lower stratosphere) and direct westward outflow from the Monsoon circulation over the Mediterranean in a first phase from Oberpfaffenhofen. In a second phase of the campaign HALO will be based in Alaska to probe eastward outflow of air from the monsoon region. Due to Rossby wave activity, the campaign base in Alaska offers a high probability to observe air masses shed of from the AMA in the lower stratosphere over the Pacific Ocean. The measurements with the GhOST instrument on HALO will provide information on a wide range of tracers, with different lifetimes and different source/sink characteristics. The emphasis of the measurements is on halogenated trace gases and in addition SF6 as mean age tracer. Depending on the set-up, the focus of the GhOST MS channel is either on the chlorine or on the bromine family. Within the proposal it is planned to perform the measurements and to use the observations for three distinct research questions related to PHILEAS: (i) What is the bromine budget in the AMA and how does this influence the lower stratosphere? (ii) What is the chlorine budget in the AMA and in air shed from the AMA? (iii) Is there an influence of anthropogenic pollution (use of e.g. CH2Cl2 or HCFC-22) or of biomass burning (CH3Cl), which could for example be related to boreal fires. In addition to these direct objectives, it is planned to further use the data for studies of global distributions of halocarbons in the tropopause region by combination with IAGOS-CARIBIC measurements funded in our group within the DFG CRC 301 (TPChange). Further, the data will be provided to and exploited in the DFG funded project QUANTITEE to investigate transit time distributions.