Solar activity and dynamics of the mesosphere and lower thermosphere

太阳活动和中间层和低层热层的动力学

• 批准号: 528774615
• 负责人: Dr. Markus Kunze
• 金额: --
• 依托单位: Institut für Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/528774615?language=en
• 关键词: Solar; activity; dynamics; mesosphere; lower

The mesosphere and lower thermosphere (MLT) region extends from 50 to 150 km in the atmosphere. It is affected from above by solar UV/EUV irradiances and precipitating energetic particles, as well as by atmospheric waves from below. So, the MLT region is an interface to couple solar energy into the atmosphere and the energy transported by atmospheric waves and tides into the thermosphere/ionosphere. Upward propagating gravity waves eventually break and dissipate there. In this way, their momentum flux divergence in the MLT drives the mean meridional circulation but also impacts the thermal structure. In turn, this dynamical feedback affects the zonal wind structure of the MLT and influences the filtering conditions for upward propagating waves generated in the lower part of the atmosphere. The energy budget of the MLT region is complex, being comprised of solar radiative heating by N2, O2, O, and O3 in the UV/EUV spectral range and IR radiative cooling by CO2 and NO, chemical heating by exothermic chemical reactions, and Joule heating of the ionospheric currents, as well as dynamical drivers. Most of these terms are affected by short-term solar variability, either directly or through chemical-dynamical feedbacks. In the proposed project, we will analyze the influence of short-term solar variability – solar EUV flares, geomagnetic storms and solar proton events – on the composition, energy budget, gravity wave propagation and dissipation, temperature, and circulation of the MLT region based on dedicated model experiments with the high-resolution high-top chemistry-climate model UA-ICON-MECCA. With this detailed analysis, we will help fill in a missing piece in understanding the energy budget of the transition region between our atmosphere and space.

中间层和低热层区域在大气层中延伸50至150公里。它受到来自上方的太阳紫外线/极紫外线辐照度和高能粒子沉淀以及来自下方的大气波的影响。因此，MLT区域是将太阳能耦合到大气中以及通过大气波和潮汐传输到热层/电离层中的能量的界面。向上传播的重力波最终会在那里破碎并消散。这样，它们在MLT中的动量通量散度驱动了平均纬向环流，但也影响了热力结构。反过来，这种动力反馈影响纬向风结构的MLT和影响的过滤条件向上传播的波在大气的下部产生的。MLT区域的能量收支是复杂的，包括在UV/EUV光谱范围内由N2、O2、O和O3引起的太阳辐射加热和由CO2和NO引起的红外辐射冷却，由放热化学反应引起的化学加热，电离层电流的焦耳加热，以及动力学驱动因素。大多数这些条款的短期太阳变率的影响，直接或通过化学动力学反馈。在拟议的项目中，我们将分析短期太阳变率-太阳EUV耀斑，磁暴和太阳质子事件-对MLT区域的组成，能量收支，重力波传播和耗散，温度和环流的影响，基于高分辨率高层化学气候模型UA-ICON-MECCA的专用模型实验。通过这种详细的分析，我们将有助于填补理解大气层和太空之间过渡区域的能量预算的缺失部分。