Winter drought variations based on tree-ring data in Gaoligong Mountain,Northwestern Yunnan,China,A. D. 1795-2004

We developed two tree ring-width chronologies of coniferous species (tsuga dumosa (d.don) eichler and abies georgei orr) in gaoligong mountain,northwestern yunnan,china. although the two chronologies come from different species,significant correlation existed between the two chronologies (r = 0.528,p<0.01),and the first principal component (pc1) accounted for 75% of total variance over their common period a. d. 1795-2005. using the pc1 of tree-ring chronologies,the winter (prior october to current january) pdsi for the research area was reconstructed for the past 210 years (r = 0.617,p<0.01). wet winters occurred during a. d.1827-1861,1880-1896 and 1922-1961,while dry winters were prevailed in a. d. 1795-1826,1862-1879,1897-1921 and 1962 to present. long-term decadal drought variations of this reconstruction fitted quite close with the variations retained in drought sensitive tree-ring series of the nearby regions,and this demonstrated the new record was confidently reliable and could capture large-scale climate signals.