Abstract
During the past decade, with few new space opportunities, many studies of the thermosphere and ionosphere have utilised data obtained from networks of ground-based instruments, interpreted with the aid of advanced theoretical and numerical models. These current methods have limitations. The thermosphere and ionosphere respond to inputs of varying spatial and temporal scales. There are global-scale energy inputs from solar UV and EUV radiation. Energy and momentum inputs from the magnetosphere are related to the mapping of the auroral ovals onto the thermosphere and ionosphere. The inputs to the thermosphere and ionosphere from the lower atmosphere have components of all scales, from the global distribution of propagating tides and planetary waves, to gravity waves which are generally thought to have intense and generally localised origins. The capabilities of some potential new techniques will also be surveyed in this review. Within the next decade, it will be possible to obtain time-sequences of large-scale images of the most important parameters and velocity flows of the thermosphere and ionosphere from space-borne instruments. Data from these new space-borne instruments will be combined with that from conventional space-borne instruments, from upgraded networks of groundbased radar and optical instruments, and from space-borne and ground-based monitors of solar and magnetospheric energy and momentum inputs. Greatly improved numerical modelling tools will also become available to aid evaluation and interpretation of these new observational data, including improved techniques for the assimilation of fragmentary observations. Recent achievements will be reviewed, and the scientific requirements for addressing the outstanding scientific problems concerning coupling between the magnetosphere, thermosphere and ionosphere and the lower and middle atmosphere.
