Characterizing soil water content variability across spatial scales from optimized high-resolution distributed temperature sensing technique

•A new method to calibrate DTS soil moisture (θ) field installations was tested.•The new calibration method resulted in a mean soil moisture RMSE of 0.03 m3m−3.•The spatial variability of θ across scales was characterized.•Number of samples needed to capture the θ variability across scales was estimated.