Influence of internal gravity waves on the thermosphere above the turbopause

垂直传播的重力内波(GW)在中间层和低热层(MLT)中的作用是众所周知的。然而，尽管越来越多的观测证据表明高热大气中的GWS活动，但对热层和电离层(TI)中的GW效应的理论研究还很缺乏。这项拟议研究的主要目的是调查起源于大气层较低的中、小型全球涛动的影响，以及它们在涡顶上方的环流中所起的作用。为此，我们新开发的系统地考虑热层破裂和耗散的GW参数化将与一个从低层大气延伸到高层热层的综合大气环流模式(GCM)相耦合。在一系列的模拟中，我们将研究GWS在所有季节、太阳和地磁活动中的动力、热和成分输送和混合效应。文中还将探讨对流层经验广谱以及对流和气象源对GWS指数的影响。这项研究的主要问题是热层在多大程度上受对流层的控制，以及是否(以及何时)存在从TI到MLT的GW中介反馈。

The role of vertically propagating internal gravity waves (GWs) in the mesosphere and lower thermosphere (MLT) is well understood. However, the theoretical research of GW effects in the thermosphere and ionosphere (TI) is lacking despite the growing number of observational evidences of GWs activity in the upper thermosphere. The main objective of the proposed study is to investigate the effects of small- and medium scale GWs of lower atmospheric origin in the TI, and the role they play in the circulation above the turbopause. For that, our newly developed GW parameterization systematically accounting for breaking and dissipation in the thermosphere will be coupled to a comprehensive general circulation model (GCM) extending from the lower atmosphere into the upper thermosphere. In a series of simulations, we shall examine the dynamical, thermal, and constituent transport and mixing effects of GWs at all seasons, solar and geomagnetic activities. The influence on the TI of GWs from empirical broad spectra in the troposphere as well as from convective and meteorological sources will be explored. The major questions of this study are how much the thermosphere is controlled by the troposphere, and if (and when) there is a GW-mediated feedback from the TI to the MLT.