IDA4D: Ionospheric Data Assimilation for the ICON Mission
G. S. Bust, T. J. Immel
Abstract
Abstract The Ionospheric Connection Explorer (ICON) mission makes measurements in near-Earth space that provide knowledge of the state of the ionosphere. From the vantage of 575 km altitude in a circular, 27° inclination orbit, it retrieves altitude profiles of the ionospheric density peak in both day and night, characterizing the abundance of oxygen ions in the main ionospheric F-layer. Further, it continuously measures plasma densities and velocities in the immediate vicinity of the observatory. These measurements provide key knowledge required for ICON’s investigations and will be regularly provided data products. They also represent an enhancement to a larger set of ionospheric measurements that are regularly obtained by extant networks. The benefit of this enhancement is realized by ingestion of ICON’s observations into assimilative models developed to provide a realistic state of the ionospheric plasma density as informed by disparate observations. ICON uses the Ionospheric Data Assimilation Four-Dimensional (IDA4D) model for this task and this report demonstrates the assimilation of simulated ICON ionospheric products into this model. The model captures observations in a 3-dimensional tomographic grid, with a temporal component that maintains “memory” of the observations in particular locales between updates, provided by ICON or other sources. The model therefore provides a unifying framework for viewing ICON measurements as part of an integrated whole-ionospheric assimilation.