A Lichenometrical Study of Snow Patch Variation in the Frederikshåb District, South-West Greenland, and its Implications for Studies of Climatic and Glacial Fluctuations.

Resumé

This report describes firstly the methods used to determine local growth rates of the species Rhizocarpon geographicum and the confidence that can be put in such estimates of substrate age based on lichen diameters. Secondly, mean Rhizocarpon geographicum diameters in former snow patch zones were sampled and non-random patterns of colonization were observed. Two models were constructed to explain these colonization patterns in terms of the change of the perennial snowline with height against time. Hence mean annual temperatures back to 1680 were predicted from the models for Frederikshab. Lastly a correlation is shown between local mean annual temperature changes in the historical period, glacial fluctuations, and estimates of temperature obtained from the lichen colonization models.