A Bayesian Reconstruction of Holocene Temperature Variation in Northern Fennoscandia

• Activity Number: 307
• Type: Topic Contributed
• Date/Time: Tuesday, August 5, 2008 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics and the Environment
• Author(s): Lasse Holmström*+ and Panu Erasto and Jan Weckstrom and Marjut Nyman and Atte Korhola
• Companies: University of Oulu and National Public Health Institute and University of Helsinki and University of Helsinki and University of Helsinki
• Keywords: Multiproxy reconstruction ; Bayesian analysis ; scale space ; SiZer ; BSiZer ; chironomids

Abstract

The arctic lakes of Northern Fennoscandia are excellent natural laboratories for the study of climatic changes. Variation in the external conditions are continuously recorded in the lake sediments for example in the form of fossils of aquatic organisms. However, different proxies, such as pollen, diatoms or chironomids have yielded different temperature reconstructions even from the same sediment record. It is therefore difficult to make any generalizations on the basis of a reconstruction made from a single record. We describe our first attempt at multi-proxy reconstruction based on two chironomid fossil records that aims to combine the signals in the records into a single "consensus" reconstruction. The reconstruction uses Bayesian modeling and the salient, time scale dependent features in the reconstruction are assessed using BSiZer scale space analysis.