caa a22 4500 605471274 CHVBK 20210128100332.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s00382-014-2328-9 doi (NATIONALLICENCE)springer-10.1007/s00382-014-2328-9 Fennoscandia revisited: a spatially improved tree-ring reconstruction of summer temperatures for the last 900years [Elektronische Daten] [Hans Linderholm, Jesper Björklund, Kristina Seftigen, Björn Gunnarson, Mauricio Fuentes] Despite the spatially homogenous summer temperature pattern in Fennoscandia, there are large spreads among the many existing reconstructions, resulting in an uncertainty in the timing and amplitude of past changes. Also, there has been a general bias towards northernmost Fennoscandia. In an attempt to provide a more spatially coherent view of summer (June-August, JJA) temperature variability within the last millennium, we utilized seven density and three blue intensity Scots pine (Pinus sylvestris L.) chronologies collected from the altitudinal (Scandinavian Mountains) and latitudinal (northernmost part) treeline. To attain a JJA temperature signal as strong as possible, as well as preserving multicentury-scale variability, we used a new tree-ring parameter, where the earlywood information is removed from the maximum density and blue intensity, and a modified signal-free standardization method. Two skilful reconstructions for the period 1100-2006 CE were made, one regional reconstruction based on an average of the chronologies, and one field (gridded) reconstruction. The new reconstructions were shown to have much improved spatial representations compared to those based on data from only northern sites, thus making it more valid for the whole region. An examination of some of the forcings of JJA mean temperatures in the region shows an association with sea-surface temperature over the eastern North Atlantic, but also the subpolar and subtropical gyres. Moreover, using Superposed Epoch Analysis, a significant cooling in the year following a volcanic eruption was noted, and for the largest explosive eruptions, the effect could remain for up to 4years. This new improved reconstruction provides a mean to reinforce our understanding of forcings on summer temperatures in the North European sector. The Author(s), 2014 Climate change nationallicence Tree rings nationallicence Density nationallicence Blue intensity nationallicence Forcings nationallicence Linderholm Hans Gothenburg University Laboratory for Dendrochronology, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden aut Björklund Jesper Gothenburg University Laboratory for Dendrochronology, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden aut Seftigen Kristina Gothenburg University Laboratory for Dendrochronology, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden aut Gunnarson Björn Department of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, Sweden aut Fuentes Mauricio Gothenburg University Laboratory for Dendrochronology, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden aut Climate Dynamics Springer Berlin Heidelberg 45/3-4(2015-08-01), 933-947 0930-7575 45:3-4<933 2015 45 382 https://doi.org/10.1007/s00382-014-2328-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-014-2328-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Linderholm Hans Gothenburg University Laboratory for Dendrochronology, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden aut NATIONALLICENCE 700 1- Björklund Jesper Gothenburg University Laboratory for Dendrochronology, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden aut NATIONALLICENCE 700 1- Seftigen Kristina Gothenburg University Laboratory for Dendrochronology, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden aut NATIONALLICENCE 700 1- Gunnarson Björn Department of Physical Geography and Quaternary Geology, Stockholm University, Stockholm, Sweden aut NATIONALLICENCE 700 1- Fuentes Mauricio Gothenburg University Laboratory for Dendrochronology, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 45/3-4(2015-08-01), 933-947 0930-7575 45:3-4<933 2015 45 382