Alpine permafrost temperature zonality, northern trans‐Baikal region, U.S.S.R.

Abstract Changes of mean annual ground temperature at the depth of zero annual amplitude ( t an ) with elevation is well known for regions of high latitude and alpine permafrost. However, this phenomenon is not sufficiently studied in the intracontinental regions of Siberia. The authors analyse the altitudinal zonality of mean annual ground temperatures ( t an ) in the Udokan Ridge, Northern Trans‐Baikal. Measurements were obtained from 321 boreholes situated on different relief elements with altitudes ranging from 830 m a.s.l. to 2170 m a.s.l. A mean integral temperature ( t * an ), as well as the range of t an variations, was determined for every 200 m altitudinal interval. The results of large‐scale geocryological mapping were used to determine t * an , which allowed one to consider the spatial distribution of landscape types characteristic of certain t an values. It is established that with increasing altitude, t * an values uniformly decrease with a gradient of ‐0.3 °C/100 m. The difference in t an between ‘cold’ and ‘warm’ landscapes changes from 2°C to 5°C for the altitudinal intervals.