Development of a Vector Spherical Harmonic (VSH) Neutral Thermosphere Model.

摘要

The Air Force has requirements for accurate knowledge and specifications of the state variables of the Earth's thermosphere. Work done under this contract has lead to a new model of global thermospheric density that can be used to specify and forecast neutral densities and winds for a wide range of solar and geomagnetic activity. The model is based on simulations made with the National Center for Atmospheric Research (NCAR) Thermosphere/Ionosphere General Circulation Model (TIGCM) and on empirical data. It is capable of using real-time geophysical indices or data from ground-based and satellite inputs and provides neutral variables at specified locations and times in the altitude range 90-1500 km. This semi-empirical model is based on a new Vector Spherical Harmonic (VSH) analysis technique developed at the University of Michigan that permits the incorporation of the TIGCM outputs and data into the model. The VSH model is being provided for use by the Air Force in an operational setting and will be a more accurate version of existing models of the neutral upper atmosphere.