榆树年轮记录的浑善达克沙地春季平均最高气温

基于采自内蒙古正蓝旗北部浑善达克沙地的榆树树芯及圆盘建立了区域年表，其与浑善达克沙地4—5月平均最高气温存在显著的负相关性（r=-0.72），根据二者的相关性建立回归方程（方差解释量为51.35%），稳定可靠，并据此重建了该地区1766—2011年4—5月平均最高气温，共246 a。重建序列中，气温显著偏高的时段有5个，显著偏低的时段有6个。采用多窗谱分析检测序列周期性，存在2~3.5 a和33~51.28 a周期。重建序列与周围地区干旱指数重建序列波动趋势具有一致性，且周围地区4—5月平均最高气温与重建的该地区4—5月平均最高气温间相关系数均高于0.6。

Elm Tree-ring Records of Spring Mean Maximum Temperature in the Otindag Sandy Land,China

There is a significant negative correlation(-0.72) between the regional chronology which build by the elm tree ring cores and disks were collected from the Otindag Sandy Land in the northern part of Zhenglan County, Inner Mongolia and the April-May mean maximum temperature of Zhenglan County. Based on this correlation we set up a regression equation between the April-May mean maximum temperature and the regional chronology, and which accounts for 51.35% of the reliability for the April-May mean maximum temperature during 1960-2011. The regression equation is credible and researched a 246-year reconstruction of April-May mean maximum temperature during 1766-2011. There were five periods with significantly higher temperatures and six periods with significantly lower temperatures by analyzing the volatility characteristics of the reconstructed sequence. There are significant cycles at 2-3.5 and 33-51.28 years of the reconstruction by using the Multi-taper method. The reconstruction sequence is consistent with the fluctuation trend of the drought index reconstruction in the surrounding area, and the correlation coefficients between the reconstruction sequence and measured sequences in surrounding areas are all higher than 0.6.