1991 Volume 43 Issue Supplement2 Pages 611-620
Some of the processes which affect the coupling of atmospheric gravity wave energy and momentum through the middle atmosphere are discussed. Changes in gravity-wave generation, propagation, and saturation can all cause variations in wave activity. Amongst the effects considered here are wave saturation, and interactions with the background wind, which act to directionaly filter and to Doppler shift wave energy. It is shown, with reference to observations, that care is required to ensure that propagation and saturation effects do not obscure the identification of wave sources, which must be one of the key goals of STEP.