Air temperature from May through August in northern Xinjiang reconstructed from multi-site tree-ring density
CHEN Feng;YUAN Yujiang;WEI Wenshou;YU Shulong;SHANG Huaming;ZHANG Tongw en;ZHANG Ruibo;WANG Huiqin;Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Tree Ring Ecology,Institute of Desert Meteorology,China Meteorological Administration;
Tree-ring density from five sites in northern Xinjiang and the Tianshan Mountains was analyzed by using principal component analysis and arithmetic average method. It is found that the first principal component of density chronology accounted for 40. 86% of the total variances of the five site density chronologies,and highly correlated with the arithmetic average of the five site density chronologies. The arithmetic average of the five site density chronologies was highly positively correlated with the May-August mean temperature averaged over the thirty-three meteorological stations in northern Xinjiang and the Tianshan Mountains. The climate/treegrowth model accounted for 44. 5% of the temperature variance from 1960 to 2008. There were six warm phases during 1656-1664,1667-1692,1711-1734,1804-1832,1855-1956 and 2000-2008. There were several severe cold phases coinciding with major volcanic eruptions. Some temperature variations also correspond to the variations in solar activity. Low-frequency change of the reconstructed temperature had correlated positively with Northern Hemisphere temperatures. The reconstructed temperature was significantly correlated with sea-surface temperature( SST) in the tropical Atlantic Ocean( positive),the North Pacific Ocean( positive) and the North Atlantic Ocean( positive). The spatial correlation patterns between the reconstructed temperature and SSTs of the Atlantic and Pacific Oceans,cloud cover,and volcanic eruptions suggested that there was a connection between regional temperature variation and the high-mid latitude northern atmospheric circulation( westerlies).