A Computational Method for Prediction and Regionalization of Permafrost

The number, a dimensionless ratio defined by manipulation of either freezing and thawing degree-day sums or frost and thaw penetration depths, can be used to define an unambiguous latitudinal zonation of permafrost continuity. The index is computed using several variables influencing the depth of frost and thaw penetration, and can be related mathematically to the existence and continuity of permafrost. Although the frost number is a useful device for portraying the distribution of contemporary permafrost at continental scales, it is not capable of detecting relict permafrost and should not be mapped over small areas unless numerous climate stations are located in the region of interest.