A STUDY OF THE JOULE AND LORENTZ INPUTS IN THE PRODUCTION OF ATMOSPHERIC GRAVITY-WAVES IN THE UPPER THERMOSPHERE

First results of a modelling study of atmospheric gravity waves (AGWs) are presented. A fully-coupled global thermosphere-ionosphere-plasmas phere model is used to examine the relative importance of Lorentz forc ing and Joule heating in the generation of AGWs. It is found that Joul e heating is the dominant component above 110 km. The effects of the d irection of the Lorentz forcing component on the subsequent propagatio n of the AGW are also addressed. It is found that enhancement of zonal E x B forcing results in AGWs at F-region altitudes of similar magnit udes travelling from the region of forcing in both poleward and equato rward directions, whilst enhancement of equatorward meridional E x B f orcing results in AGWs travelling both poleward and equatorward, but w ith the magnitude of the poleward wave severely attenuated compared wi th the equatorward wave.