Precipitation variability during the past 400 years in the Xiaolong Mountain (central China) inferred from tree rings

We developed the first tree-ring chronology, based on 73 cores from 29 Pinus tabulaeformis trees, for the Xiaolong Mountain area of central China, a region at the boundary of the Asian summer monsoon. This chronology exhibits significant (at 0.01 level) positive correlations with precipitation in May and June, and negative correlations with temperature in May, June and July. Highest linear correlation is observed between tree growth and the seasonalized (April-July) precipitation, suggesting that tree rings tend to integrate the monthly precipitation signals. Accordingly, the April-July total precipitation was reconstructed back to 1629 using these tree rings, explaining 44.7 % of the instrumental variance. A severe drought occurred in the area during the 1630s-1640s, which may be related to the weakened Asian summer monsoon caused by a low land-sea thermal gradient. The dry epoch during the 1920s-1930s and since the late 1970s may be explained by the strengthened Hadley circulation in a warmer climate. The dry (wet) epochs of the 1920s-1930s (the 1750s and 1950s) occurred during the warm (cold) phases of the El Niño-Southern Oscillation and the Pacific Decadal Oscillation that are often associated with weakened (strengthened) East Asian summer monsoon. These relationships indicate significant teleconnections operating over the past centuries in central China related to large-scale synoptic features.