Retrospective and Operational Data Analysis in the Whole Atmosphere Models: Challenges and Perspectives

The paper will discuss the current status, challenges and perspectives for the operational and retrospective data analysis of the lower and upper atmosphere observations in the whole atmosphere models that provide space weather predictions in the coupled atmosphere-ionosphere system. We will overview the recent progress in constraining the neutral dynamics and transport of the Ionosphere-Thermosphere-Mesosphere (ITM) region by assimilating observations made by the NASA satellite missions. The role of Observing System Simulation Experiments (OSSEs) will be emphasized to constrain the strong diurnal variations of ITM by the vertical profile data and to properly analyze the deep layer averaged information from nadir-viewing instruments. The absence of the near-real-time (NRT) observations for operational data assimilation in the upper stratosphere and ITM represents the current challenge to constrain the neutral dynamics and composition in the upper layers of the Whole Atmosphere Model (WAM). The retrospective data analysis of the multi-year wind, temperature and constituents made by TIMED, EOS Aura, GOLD and ICON instruments, however, will be a potential pathway to verify and improve predictions in the upper atmosphere, including forecasts performed by operational space weather model, WAM-IPE. The data-driven identification of systematic model errors and revision of model formulations can be envisioned along with data-driven bias correction schemes to enhance space weather forecasts of neutral dynamics and transport in the ITM with the rapid operational data analysis of observations below the stratopause.