Towards a quantification of vortex impact on the arctic lowermost stratosphere

量化涡旋对北极最低平流层的影响

• 批准号: 522359443
• 负责人: Professor Dr. Peter Hoor
• 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
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/522359443?language=en
• 关键词: Towards; quantification; vortex; impact; arctic

The lowermost stratosphere of the polar regions is charecterized by diabatic downwelling from the vortex, downward transport in mid latitude stratosphere and mixing from low latitudes as part of the lower branch of the Brewer-Dobson circulation. In lower altitude mixing across the extratropical tropopause additionally contributes leading to the formation of the extratropical transition layer (ExTL). In the northern hemisphere a considerable variability due to the intraannual variability of the dynamical conditions leads to a high interannual variability of the arctic LMS composition. In this proposal we want to quantify the contribution of the main reservoirs. We will do this on the basis of fast (1-3Hz) airborne measurements of different tracers. We will use the newly added species ethane (C2H6) as an indicator for aged vortex air. Combined with N2O, CO we set up a budget to infer the relative contributions from the relevant source regions of air to qunatify the impact of vortex air on the lowermost stratosphere. We will further determine the impact of the tropospheric fraction constituting the ExTL and compare the vertical extent of the ExTL for different years (winter 2015/2016) and the southern hemisphere (SOUTHTRAC) to infer information about the variability of the ExTL depths under different dynamical conditions. Finally we will study the interaction of former vortex filaments with the lowermost stratospheric background. We will specifically focus on filaments subject to strong shear or passing regions of gravity wave activity, which both my lead to dynamical instability and turbulence. We will study mixing between these filaments and the surrounding air and infer tracer fluxes for such events.

极区平流层最低层的特征是来自涡旋的非绝热下降流、中纬度平流层的向下输送和作为Brewer-Dobson环流低分支一部分的低纬度混合。在较低的高度，对流层顶外的混合也有助于形成对流层外过渡层（ExTL）。在北方的一个相当大的变化，由于动力条件的年际变化导致北极LMS组成的年际变化。在本提案中，我们希望量化主要水库的贡献。我们将根据不同示踪剂的快速（1- 3 Hz）机载测量结果来进行这项工作。我们将使用新添加的物质乙烷（C2 H6）作为老化涡流空气的指标。结合N_2O、CO建立了一个收支模型，以推求各相关源区的相对贡献，定量化涡旋空气对平流层最低层的影响。我们将进一步确定构成ExTL的对流层部分的影响，并比较不同年份（2015/2016年冬季）和南半球（SOUTHTRAC）ExTL的垂直范围，以推断不同动力条件下ExTL深度变化的信息。最后，我们将研究前涡丝与平流层最低层背景的相互作用。我们将特别关注受到强剪切或通过重力波活动区域的细丝，这两者都可能导致动力学不稳定和湍流。我们将研究这些细丝和周围空气之间的混合，并推断这些事件的示踪剂通量。