The non–storm time corrugated upper thermosphere: What is beyond MSIS?

Abstract

Abstract Observations in the recent decade have revealed many thermospheric density corrugations/perturbations under nonstorm conditions ( K p < 2). They are generally not captured by empirical models like Mass Spectrometer Incoherent Scatter (MSIS) but are operationally important for long‐term orbital evolution of Low Earth Orbiting satellites and theoretically for coupling processes in the atmosphere‐ionosphere system. We review these density corrugations by classifying them into three types which are driven respectively by the lower atmosphere, ionosphere, and solar wind/magnetosphere. Model capabilities in capturing these features are discussed. A summary table of these corrugations is included to provide a quick guide on their magnitudes, occurring latitude, local time, and season.