Occurrence of Unfrozen Ground in Finland

• Main Author: Reijo Solantie
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Key words; Soil frost; Fennoscandian
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.516.5128; http://www.geophysica.fi/pdf/geophysica_1998_34_3_141_solantie.pdf

In the area of the Fennoscandian inland climate, which is rather mild and rainy, the soil occasionally remains unfrozen under a deep snow cover. The frequency of such conditions varies strongly between regions. Sites providing soil temperature and soil frost observations are too few for a reliable regional analysis. Annual grid point charts of snow depth on March 15th for open fields and forests are, however, available; their analysis gives charts with a high spatial resolution corresponding to various percentage points in the temporal distribution of snow depths. Regression equations were derived, giving the frequency of unfrozen ground as a function of P0.33/D6 where P denotes the average frost sum, the exponent is empirical and D6 is the snow depth on March 15th exceeded in 6 out of 100 winters, which is of the same order as the frequency of winters with unfrozen ground. Applying the resulting regression equations, charts with a high spatial resolution could be made for the frequency of unfrozen soil for open fields and forests. Good agreement was found with the distributions of several ecological and agricultural phenomena related to the occurrence of unfrozen ground.