Erosion of Permafrost Coasts

Introduction

In the lowlands of the Laptev Sea changes in permafrost thickness and distribution are closely related to natural global climate cycles. The region is mainly controlled by variations in continentality and glacio-eustatic sea level changes because it has never been glaciated. During glacials, which are characterised by an increase in continentality and a marine regression, permafrost is formed on the dry shelves. On the other hand, during interglacials, the decrease in continentality and the marine transgression results in degradation of permafrost. In the coastal zone these changes are mainly related to the influence of saline sea water.

The objectives of this project are

• to reconstruct the spatial and temporal variability of permafrost in the Laptev Sea region and

• to identify and understand the processes that control this variability.

The Laptev Sea coastline currently undergoing erosion represents a natural laboratory to study these processes.

The work programme covers

• the quantification of coastal retreat rates as a function of both coastal characteristics (morphology, composition, ice content etc.) and environmental forcing (water temperatures, wave activity, storminess etc.),

• the investigation of interactions between permafrost and sea water as documented in shallow drill sites,

• the mathematical modelling of the permafrost distribution taking into account the factual data obtained during field work.