THE EFFECT OF FREEZEBACK TIME ON THE MEAN ANNUAL GROUND TEMPERATURE IN CENTRAL YAKUTIA
Varlamov Stepan Prokopievich (1)
(1) Melnikov Permafrost Institute, Siberian Branch, Russian Academy of Sciences
The paper discusses variations in the dates of complete freezing of the seasonally thawed layer and their effect on the mean annual ground temperature.
Field investigations in Central Yakutia indicate that the depth of seasonal thawing varies over a wide range of 0.5 to 4.3 m, depending on mechanical composition, vegetation, surface cover, and ground moisture content.
In 1982-1998, the dynamics of seasonal thawing/freezing in various landscapes was studied in the Yakutsk area, covering almost the entire range of the seasonal thaw depth variations for Central Yakutia. During these years the length of a thawing period ranged from 141 to 156 days, averaging 150 days. The dates when the freezing boundary reaches the permafrost table vary greatly (from mid-October through late-April) depending on terrain conditions. In some years a residual thaw layer may form. Freezeback time within the same terrain unit also varies greatly from year to year, depending on the weather conditions in winter and the characteristics of the seasonally thawed layer. The variation is up to 80-90 days.
Based on the field data, regional empirical relationships have been established among the mean annual ground temperature at the base of the seasonally thawed layer, the length of a freezeback period, and the air freezing index after freezeback.
Submittal Information
Name :
Date :
Varlamov Stepan Prokopievich
21-May-01-15:38:06
Organization :
Theme :
Melnikov Permafrost Institute, Siberian Branch, Russian Academy of Sciences
