351-year tree ring reconstruction of the Gongga Mountains winter minimum temperature and its relationship with the Atlantic Multidecadal Oscillation

Scarcity of high-resolution proxy records has hindered our understanding of long-term climate variations and their mechanism in climate-sensitive regions such as the Tibetan Plateau (TP). In this study, we present a winter minimum temperature (Tmin) reconstruction for the past 351 years (1648–1998) based on a composite tree ring width chronology from three upper treeline sites in the Gongga Mountains, southeastern TP. Despite a loss of sensitivity to winter Tmin after the 1990s, tree growth agrees well with previous December to current March (pDec-cMar) Tmin during 1953–1998, and a regression model based on climate-tree growth relationship over this period explains 52% of the instrumental Tmin variance. The resulting reconstruction exhibits three major cold (1670–1745, 1805–1853, and 1877–1949) and four major warm (1648–1669, 1746–1804, 1854–1876, and 1950–1998) periods over the past four centuries. Long-term winter Tmin variations in the Gongga Mountains have high coherence with those represented by temperature reconstructions in the nearby regions. Together, they indicate close association of the reconstructed warm/cold periods with the positive/negative phases of the Atlantic Multidecadal Oscillation (AMO), suggesting that the AMO may have been a key driving force affecting regional climate over the past few centuries.