2024 Workshop: ITM climate and trends
Wenbin Wang
Liying Qian
Joseph McInerney
Shunrong Zhang
Dong Lin
Susan M Nossal
This session invites both observational and modeling studies of climate and trends (longer than a solar cycle) of the ionosphere-thermosphere-mesosphere (ITM) in different timescales. The ITM system is strongly coupled with the geospace environment above it and the lower atmosphere below it. The complex external coupling processes and the internal physical and chemical processes lead to significant global variations in different time scales, including those from seasonal to decades. However, the discontinuous observation in the long term makes it challenging to investigate the long-term changes in the ITM system and the causes of it. In recent years, the advantage of numerical simulations and the increasing number of observations have helped improve our understanding of the variation of the ITM system on these time scales. In this workshop, we will discuss the variations of the ITM system on climate and trends time scales and the mechanisms behind them.
The ITM system shows significant global variation in different time scales, including seasonal variation, solar-cycle variation, and decades-long trend. The coupling between internal processes and external forcings from above and below leads to these complex variations in the ITM system. The variation and the long-term trend of the ITM system cause the change of neutral density in the upper atmosphere and further show a strong impact on the satellite drag and orbit determination. Therefore, understanding the contribution of different internal processes and external forcings to the variation and long-term trend of the ITM climate is critical due to the blooming development of space technology that we increasingly rely on.