Retrieving a common accumulation record from Greenland ice cores for the past 1800 years

• Main Authors: K. K. Andersen, P. D. Ditlevsen, S. O. Rasmussen, H. B. Clausen, B. M. Vinther, S. J. Johnsen
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2006
• Subjects: Greenland; Greenland ice cores; Ice Sheet
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.524.7801; http://www.gfy.ku.dk/~pditlev/papers/GreenlandAccumulation.pdf

Abstract. In the accumulation zone of the Greenland ice sheet the annual accumulation rate may be determined through identification of the annual cy-cle in the isotopic climate signal and other parameters that exhibit seasonal vari-ations. On an annual basis the accumulation rate in different Greenland ice cores is highly variable, and the degree of correlation between accumulation series from different ice cores is low. However, when using multi year averages of the dif-ferent accumulation records the correlation increases significantly. A statistical model has been developed to estimate the common climate signal in the differ-ent accumulation records through optimization of the ratio between the variance of the common signal and of the residual. Using this model a common Green-land accumulation record with five years resolution for the past 1800 years has been extracted. The record establishes a climatic record which implies that very dry conditions during the 13th century together with dry and cold spells dur-ing the 14th century may have put extra strain on the Norse population in Green-land and have contributed to their extinction.