Whole Atmospheric Global Balanced Wind and Thermodynamic States from the Ground to the Lower Thermosphere

Abstract

Korea Polar Research Institute has been operating instruments to observe and estimate atmospheric state variables in the mesosphere and thermosphere in the polar regions (Kim et al. 2012). It is also found that those observations can give insights on gravity wave activities in the upper atmosphere (Lee et al. 2013). To understand more precisely how the observed upper atmospheric phenomena are generated or propagated from the other regions, numerical modeling and its comparison with observations are necessary. Comparison between model results and observations for specific events requires numerical model to start from a time prior to specific observation date and time. For this, a proper initialization of model is essential. Without appropriate initialization, spurious initial high-frequency noises due to unbalanced atmospheric states contaminate model results even at a later time (Daley 1991). Purpose of the present research is to generate balanced atmospheric state variables from the ground to the lower thermosphere at specific date and time. Since our major interest is in simulating already observed phenomena rather than in forecasting, the state variables are obtained using pre-existing analysis data for the troposphere and stratosphere. Above the stratopause, empirical horizontal wind and temperature models are used. The separate data sets and empirical model results are combined using data-fusion method. Finally, a balanced atmosphere state is derived from the combined data at a specific date and time using a global primitive equation dynamical model. Using global model is preferred to regional model since upper atmospheric phenomena such as gravity waves observed at a certain location can be generated in the other regions far from the observation site (Liu et al. 2014).