Empirical modeling of particle precipitation and the study of effects on the terrestrial thermosphere and ionosphere

In order to study the effects of particles of solar origin on the atmospher ic system, the construction of a particle climatology has been adopted as a n activity of the International Solar Cycle Study, Working Group-1, Panel-2 . The activity is incorporated within the Thermosphere Ionosphere Geospheri c Research (TIGER) program. This climatology is an empirical model of parti cle input providing average spectral characteristics, precipitating particl e fluxes, and ionization rate profiles as functions of latitude, local time , and activity level. It is being built upon a model already being develope d with particle data from the Upper Atmosphere Research Satellite (UARS). I n this paper we describe the development of the UARS particle climatology a nd show how it is being extended to improve spatial and temporal coverage. We discuss the use of the climatology in global circulation and assimilativ e modeling and provide the status of its use such models in Thermosphere-Io nosphere modeling to date, (C) 2000 Elsevier Science Ltd. All rights reserv ed.