This release corresponds to the version of the code used for the submission of: Moshtaghian et al. (2026), "Frequency-domain Airborne Electromagnetic Imaging of Permafrost Reveals Heterogeneity and Drivers of Permafrost Change in the Discontinuous Permafrost Zone of Northwestern Canada", submitted to AGU Advances. This version is archived to ensure full computational reproducibility of all figures and results presented in the manuscript. Core components included: 1D frequency-domain AEM inversion using SimPEG Depth of Investigation (Oldenburg & Li, 1999; Christiansen & Auken, 2012) Center-based gradient permafrost base detection Permafrost Base Transition Zone (PBTZ) estimation Reproducible plotting and RMS misfit diagnostics This release is intended as the frozen submission version. Subsequent minor updates (e.g., citation formatting after publication) will not alter this archived snapshot.