Distribution of permafrost in Finland

Abstract

Two main types of permafrost are found in northern Finland. The most widely known occurence is in mires, in peat mounds with permanently frozen cores known as palsas. Some fully new, small occurrences have been found in pounus, small peat humps over large areas in Lapland. The second main type of permafrost occurrence is located above the tree line on barren fell summits there permafrost means continuous temperature below 0°C in the bedrock .Some massive cave ice has been found in Lapland, too. The climatic conditions at permafrost sites are still poorly know because the local topography affects the temperature conditions. Only sporadic recordings are available from the summits of fells and from palsa mires. In general, the mean annual air temperature for permafrost formation should be below -1°C. Snow depth seems to be the most critical factor for permafrost formation in Lapland: thin snow cover promotes frost penetration. Vegetation provides a useful indicator of snow depth and of possible permafrost sites. Some proposals are made for permafrost studies in Lapland.

Keywords

• periglacial features
• permafrost
• palsas
• mires
• bedrock
• climate
• topography
• snow
• soils
• vegetation
• Lapland
• Finland