Prakash Poudel, Xian Lu
Abstract We investigate Ionosphere‐Thermosphere (IT) responses to the March 2023 geomagnetic storm using GOLD and PFISR observations, along with TIEGCM simulations driven by data‐assimilated aurora and electric fields. A Lattice Kriging approach is implemented to assimilate auroral electron flux and characteristic energy from ground‐based (THEMIS/ASIs) and satellite (DMSP/SSUSIs) measurements, and the empirical model (Zhang & Paxton, 2008, https://doi.org/10.1016/j.jastp.2008.03.008 ). Electric field assimilation uses SuperDARN ion drifts, PFISR, and the SuperDARN SHF potential model. Compared to the default run, the assimilated simulation better captures GOLD observations, including an O/N 2 depletion by ∼0.5, and a neutral temperature enhancement of ∼170 K relative to a quiet day. These changes are primarily driven by enhanced Joule heating from assimilated aurora and electric fields, and the resultant upwelling. Results from different model runs implies that aurora modestly increases temperature, while electric fields further enhance it and modulate its spatial structure. The assimilated run also captures the local PFISR observations, including (a) F‐region elevated ion and electron temperatures (∼4000 K); (b) a negative ionospheric storm phase with ∼60% F‐region electron density reduction; and (c) E‐region electron density enhancements by 50%, relative to a quiet day. Electric fields more strongly elevate ion temperature and reduce F‐ region electron density, whereas aurora drives E‐region electron density enhancements. The combined effect of both drivers produces the largest height‐integrated Joule heating at the Poker Flat, reaching ∼120 mW/m 2 . Overall, we demonstrate that assimilating high‐latitude drivers into TIEGCM significantly improves its capability to simulate storm‐time IT dynamics with richer spatial structures and increased variability.