Investigation of nonmigrating thermospheric tidal waves in density and wind as observed by CHAMP

热层的状态及其温度分布受多种因素的影响。主要的过程是由太阳加热驱动的大气潮汐。这些潮汐波每天都在全球传播。在潮汐与局部过程的干扰下，产生二次波。次级波的特殊类型是非迁移潮汐。这个项目的重点是研究热层密度和风中的非迁移特征。非迁移波的强迫可以来自下面或通过热层内部的相互作用。有迹象表明，低层大气中的过程，如潜热的释放，可以调节潮汐波。它的目的是找出，与热层的耦合有多有效。局部的热层气流也可以被离子阻力所改变。通过这个过程，地磁场获得了对热层的控制。CHAMP卫星提供了自2000年中期发射以来的空气密度和风的测量数据。根据这组数据，我们计划识别这些潮汐特征，并将它们与底部热层的大气特征联系起来，正如大气模型所预测的那样。与离子阻力有关的特征将与电离层密度、电流系统和电场的特征相关联。

The state of the thermosphere and its temperature distribution are influenced by many factors. Dominant processes are atmospheric tides driven by solar heating. These tidal waves travel around the globe every day. In case of interference of the tides with local processes secondary waves are generated. Particular types of secondary waves are nonmigrating tides. This project is focussing on the investigation of nonmigrating signatures in the thermospheric density and winds. The forcing of nonmigrating waves can come from below or through interactions within the thermosphere itself. There is indication that processes in the lower atmosphere, such as the release of latent heat, can modulate the tidal wave. It is intended to find out, how efficient the coupling into the thermosphere is. Locally, the thermospheric air flow can also be modified by ion drag. Through this process the geomagnetic field gains control on the thermosphere. The CHAMP satellite provides measurements of the air density and winds since its launch, middle of 2000. Based on this data set we plan to identify these tidal signatures and correlate them with atmospheric features at the bottom side thermosphere, as predicted by an atmospheric model. The signatures related to ion drag will be correlated with features in ionospheric density, current systems and electric fields.