title: Interannual variability of average minimum temperatures derived from tree rings in the mid-Qinling Mountains, China, for the past 138 years.
abstract: In this study, spruce tree rings from the southern slope of mid-Qinling Mountains were adopted to investigate the characteristics of average minimum temperatures during the past 138 years. Analysis showed that the interannual variability in radial growth of trees was positively correlated with the interannual variability of average minimum temperatures from previous December to current September (VTMDS) in the study area during 1955-2010 AD. Based on the correlation analysis, the VTMDSwere reconstructed for 1876-2013 AD with an explained variance of 42.5 % for the calibration period. Among the 22 dramatic changing years, extreme changes occurred more times when it was cooling, while the warming was comparatively gentle. Both the 10-year filtering of VTMDSseries and the frequency of occurrences for those dramatic changing years showed a relatively stationary variation after the early 1950s. Over the last five decades, the accumulated VTMDSseries showed an obvious warming trend, and the increase of the minimum temperature had contributed to the regional warming. The comparison of VTMDSand the dryness/wetness indices generally reflected cold-wet and warm-dry climate conditions in the study area. Significant positive correlations between the reconstructed VTMDSand the gridded minimum temperature indicated a regional representative of the temperature reconstruction, and positive correlations between VTMDSand sea surface temperature (SST) of the Indian Ocean and western Pacific regions suggested a possible linkage between the VTMDSvariations and the Asian summer monsoon. Synchronous fluctuations in three tree-ring study series and connections of VTMDSwith Arctic oscillation (AO) and El Niño-Southern Oscillation (ENSO) activities suggested that the minimum temperature variations in the TTH area responded sensitively to large-scale climate fluctuations and were the results of atmosphere-ocean interactions.
authors.affiliation: The State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Lei
authors.affiliation: The State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China. liuyu@loess.llqg.ac.cn.|Department of Environmental Science and Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China. liuyu@loess.llqg.ac.cn.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Resources, Environment, and Urban Sciences, Xianyang Normal University, Xianyang, 712000, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Sun
authors.affiliation: Department of Environmental Science and Technology, School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
authors.forename: Changfeng
authors.initials: C
authors.lastname: Sun
mesh_terms: D002681:China; D065928:Forests; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D028222:Picea / Q000254:growth & development*; D013696:Temperature; D014197:Trees / Q000254:growth & development*
keywords: Average minimum temperatures; Mid-Qinling Mountains; Picea asperata; Reconstruction; TTH