Towards whole-atmosphere modeling: A coupled model of Integrated Dynamics through Earth's Atmosphere (IDEA)

The upper atmosphere and ionosphere exhibit variability on global scales with periods from several hours to several days, characteristic of lower-atmospheric planetary waves and tides. To study the origin, vertical propagation, and possible effects of these planetary-scale perturbations on the coupled thermosphere-ionosphere-electrodynamics system, a new model of Integrated Dynamics through Earth Atmosphere (IDEA) is being developed under a NASA sponsored collaborative project between the University of Colorado and National Weather Service's (NWS) Environmental Modeling and Space Environment Centers. IDEA interactively couples a Whole Atmosphere Model (WAM) with Global Ionosphere-Plasmasphere (GIP) and electrodynamics models. WAM is a 150-layer general circulation model (GCM) based on NWS's operational weather prediction Global Forecast System (GFS), extended from its nominal top altitude of about 60 km to over 600 km. It incorporates relevant physical processes in the extended domain, ranging from the hydrological cycle, cloud physics, and atmosphere-surface exchanges in the troposphere, to solar and Joule heating and mutual diffusion of major species in the thermosphere. The model extension into a domain of highly variable composition and very low density requires certain generalization of the standard GCM framework, which may be of interest for middle and even lower atmosphere modeling and will be briefly discussed. Preliminary simulations, revealing highly variable dynamics in the middle and upper atmosphere, will also be presented.