title: Sensitivity of proxies on non-linear interactions in the climate system.
abstract: Recent climate change is affecting the earth system to an unprecedented extent and intensity and has the potential to cause severe ecological and socioeconomic consequences. To understand natural and anthropogenic induced processes, feedbacks, trends, and dynamics in the climate system, it is also essential to consider longer timescales. In this context, annually resolved tree-ring data are often used to reconstruct past temperature or precipitation variability as well as atmospheric or oceanic indices such as the North Atlantic Oscillation (NAO) or the Atlantic Multidecadal Oscillation (AMO). The aim of this study is to assess weather-type sensitivity across the Northern Atlantic region based on two tree-ring width networks. Our results indicate that nonstationarities in superordinate space and time scales of the climate system (here synoptic- to global scale, NAO, AMO) can affect the climate sensitivity of tree-rings in subordinate levels of the system (here meso- to synoptic scale, weather-types). This scale bias effect has the capability to impact even large multiproxy networks and the ability of these networks to provide information about past climate conditions. To avoid scale biases in climate reconstructions, interdependencies between the different scales in the climate system must be considered, especially internal ocean/atmosphere dynamics.
authors.affiliation: Department of Geography, University of Bonn, 53115 Bonn, Germany.
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Schultz
authors.affiliation: Institute of Geography, University of Augsburg, 86159 Augsburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Beck
authors.affiliation: Department of Geography, University of Bonn, 53115 Bonn, Germany.
authors.forename: Gunter
authors.initials: G
authors.lastname: Menz
authors.affiliation: DeLaWi Dendro Lab Windeck, 51570 Windeck, Germany.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Neuwirth
authors.affiliation: Hans-Ertel-Centre for Weather Research, Meteorological Institute, University of Bonn, 53121 Bonn, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Ohlwein
authors.affiliation: Institute of Geography, University of Augsburg, 86159 Augsburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Philipp