Simultaneous Multi-scale Data Assimilation of GOES-16 ABI All-Sky Radiances for a Dryline Convection Event

This study investigates the impact of simultaneous Multi-scale Data Assimilation (MDA) of GOES-16 Advanced Baseline Imager (ABI) infrared all-sky radiance on a dryline convection event from 27 May 2019, compared to the Single-scale Data Assimilation (SDA). The convection, which included tornadic supercells and a bowing Mesoscale Convective System (MCS) over the continental United States, was influenced by multiple scales including upper-level jet, short-wave trough, dryline, and storm scale dynamics. The simultaneous MDA of GOES-16 ABI all-sky radiance, in addition to radar reflectivity assimilation, is performed using Scale-Dependent Localization (SDL) and Variable-Dependent Localization (VDL) within the Ensemble Variational DA system. The MDA configuration, including scale separation and covariance localization, is optimized by examining ensemble perturbations across multiple scales. Single observation tests and correlations between brightness temperatures and model state variables indicate that the MDA of all-sky radiance more effectively analyzes both small- and large-scale features compared to the SDA. Cycled DA experiments assimilating all sky radiance and reflectivity demonstrate that the MDA better enhances the upper-level jet and short-wave trough, aligning them more closely with the dryline convection compared to the SDA. These improvements in the MDA analysis lead to better predictions of tornadic supercell tracks and the organization and maintenance of the bowing MCS during the 6-hour forecast period compared to the SDA.