Modelling the temporal dynamics of subarctic surface temperature inversions from atmospheric reanalysis for producing point-scale multi-decade meteorological time series in mountains

The vertical profile of air temperatures in subarctic regions is difficult to quantify, especially in areas with mountainous terrain subject to strong and lasting inversion events. Relying on observational data is not possible in most places due to sparse weather stations. To address this gap, we use reanalysis data to produce a model of the inversion strength. This model uses a single downscaled atmospheric column from reanalysis data and is calibrated with five weather stations close to Dawson City, Yukon, situated at various elevations. It is shown to perform better than bare reanalysis products and its parameters take into account the observed long-term decrease in frequency, strength, and depth of inversions since 1948, departing from the pattern of elevation-dependent warming found in lower latitude mountain regions. Once calibrated, the model only relies on global reanalysis data and hence can be applied in the vicinity of the calibration site, even where no observational data are available. Producing reliable time series for air temperature in complex terrain where inversions are strong and frequent is essential in modelling permafrost and understanding its future evolution. This model uses ever-improving physically based data, making it future-proof and versatile in its regional applications.