DORIS Observations from LEO for 3D Space Weather

Study of the upper and lower atmosphere has advanced to the point where a compelling need has emerged for global real-time specification of the most important observations as inputs to climate and other high-resolution assimilative models. For the ionosphere, plasmasphere and magnetosphere this is the local free electron density (ED); for the troposphere it is the local water vapor content (WVC). Currently, available data describes only the synoptic (few to tens of degrees) ionospheric features, but future needs require mesoscale (tens to hundreds of km) description. We describe a system concept for a DORIS receiver to be flown on a future constellation of weather satellites that would provide precise real-time global specifications of ionosphere 3D electron density profile (EDP) and troposphere WVC, as well as ionospheric scintillation maps at two length scales. We emphasize the ionospheric feature sizes that could be resolved - 100 km scale or less horizontally - and how the data sets obtained could help illuminate the transition from persistent to turbulent structures. We show how the DORIS frequency lever arm is superior to that of GPS for probing the ionosphere, and how DORIS data is currently being used to generate WVC data sets of comparable precision to GPS and VLBI data.