利用树轮密度重建新疆北部5-8月温度变化

Air temperature from May through August in northern Xinjiang reconstructed from multi-site tree-ring density

利用新疆北部5个采样点的树轮密度年表主序列和新疆北部33个气象站观测气温平均值进行相关分析,结果显示其与新疆北部5-8月平均温度存在很强一致相关性,相关系数为0.667(p<0.001,n=49)。温度重建方程能够解释校准期(1960-2008年)内44.5%的温度变化方差。空间相关分析揭示该温度重建序列能够表征新疆北部过去353 a(1656-2008年)5-8月温度总体变化特征。重建序列揭示新疆北部5-8月平均温度大致经历了6个偏暖阶段,即1656-1664年、1667-1692年、1711-1734年、1804-1832年、1855-1956年、2000-2008年,中间为偏冷阶段,这些阶段中间多个小幅度变化。温度重建结果发现新疆北部温度变化与太阳活动、火山喷发有着紧密联系。温度重建序列与全球海温场的相关分析显示当西风带海区及热带大西洋地区的海温偏高时,研究区气温偏高。与海温、火山喷发和云量变化的相关分析都指示在西风环流的作用下,上述因子对于该地区温度变化有着重要影响。该温度重建序列在低频变化上与北半球气温具有显著正相关,说明中亚地区温度变化与北半球整体温度变化具有较好的一致性。

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/tree-growth 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）.