Publication details

Last millennium Northern Hemisphere summer temperatures from tree rings: Part II, spatially resolved reconstructions

Authors	ANCHUKAITIS Kevin J. WILSON Rob BRIFFA Keith R. BÜNTGEN Ulf COOK Edward R. D'ARRIGO Rosanne DAVI Nicole ESPER Jan FRANK David GUNNARSON Björn E. HEGERL Gabi HELAMA Samuli KLESSE Stefan KRUSIC Paul J. LINDERHOLM Hans W. MYGLAN Vladimir OSBORN Timothy J. ZHANG Peng RYDVAL Milos SCHNEIDER Lea SCHURER Andrew WILES Greg ZORITA Eduardo
Year of publication	2017
Type	Article in Periodical
Magazine / Source	Quaternary Science Reviews
MU Faculty or unit	Faculty of Science
Citation
Web	https://doi.org/10.1016/j.quascirev.2017.02.020
Doi	http://dx.doi.org/10.1016/j.quascirev.2017.02.020
Keywords	Tree-rings; Northern Hemisphere; Last millennium; Common Era; Summer temperatures; Reconstruction; Spatial
Description	Climate field reconstructions from networks of tree-ring proxy data can be used to characterize regional scale climate changes, reveal spatial anomaly patterns associated with atmospheric circulation changes, radiative forcing, and large-scale modes of ocean-atmosphere variability, and provide spatiotemporal targets for climate model comparison and evaluation. Here we use a multiproxy network of tree-ring chronologies to reconstruct spatially resolved warm season (May August) mean temperatures across the extratropical Northern Hemisphere (40-90 degrees N) using Point-by-Point Regression (PPR). The resulting annual maps of temperature anomalies (750-1988 CE) reveal a consistent imprint of volcanism, with 96% of reconstructed grid points experiencing colder conditions following eruptions. Solar influences are detected at the bicentennial (de Vries) frequency, although at other time scales the influence of insolation variability is weak. Approximately 90% of reconstructed grid points show warmer temperatures during the Medieval Climate Anomaly when compared to the Little Ice Age, although the magnitude varies spatially across the hemisphere. Estimates of field reconstruction skill through time and over space can guide future temporal extension and spatial expansion of the proxy network.