DReaMIT: A Dynamical Reanalysis Framework for Modelling Surface-Based Temperature Inversions in Cold Environments

Abstract. Surface-based temperature inversions (SBIs) are critical to high-latitude mountain climatology, shaping permafrost stability and near-surface thermal regimes. This study develops and evaluates a new surface-based inversion model, DReaMIT (Dynamical Reanalysis Model for Inversions of Temperature), that extends the framework of (Pozsgay and Gruber, 2025) by spatializing the inversion strength parameter (α) using hypsometric position rather than absolute elevation. The reformulated approach enables a unified calibration across two contrasting Yukon valleys (WS01 and WS02), improving model transferability and reducing site-specific bias. Exponentiation of the elevation variable captures the observed nonlinear decay of lapse rates within SBIs, consistent with in-valley observations where temperature increases of up to 8 °C over 19 m were recorded. Model performance was assessed across the Yukon and Northwest Territories, where it successfully reproduced inversion structure even in areas with weaker or transient SBIs, such as Whitehorse and Haines Junction. Limitations were observed in flat regions with minimal hypsometric relief (e.g., Tulita, Old Crow), highlighting cases where microtopographic indices may better represent cold-air pooling potential. The new hypsometric formulation enhances the physical realism and spatial applicability of SBI modelling, providing an empirically-constrained, transferable tool for predicting near-surface temperature regimes and assessing permafrost sensitivity under northern climate change.