天山北坡西部树木年轮对气候因子的响应分析及气温重建

Response of Tree-ring to Climate Change and Temperature Reconstruction in West of Tianshan Mountains North Slope

利用博尔塔拉蒙古自治州三个采点的树轮宽度年表，通过相关和响应面分析的方法，分析三个树木年轮宽度对气候因子的响应。分析表明，三个年表与博州地区的年平均最低气温和7月降水量呈较显著的正相关，且呈现相同的响应，仅在气温偏低时，三个年表响应不一致。通过分析，选择年最低气温作为重建对象，具有明显的树木生理学意义。利用树轮年表重建了博州1576—2002年的年最低气温，通过逐一剔除检验，发现重建值稳定可靠。在427a中，存在2～3a和40～50a左右的周期性振荡，1631年、1832年、1920年和1961年左右发生过突变。

The Boertala Mongolia Autonomous Prefecture is located on the western Tianshan Mountains＇ north slope, belonging to the semi-arid area of Northwest China. Three tree-ring increment cores of Picea schrenkiana Var tiansclhanica were sampled from the upper tree lines in Boertala. Three standardized chronologies were developed by using a 100-year Spline Function. Single correlation analyzing result indica- ted that the relations were significant among the three tree-ring width chronologies and climate factors; the greatest coefficient （R =0. 512） is relation with annual minimum temperature, and that with precipitation in July is 0. 456, their significance are all greater than the 99.9 percent level. Response analysis proved the same correlation between tree-ring chronologies and annual minimum temperature and precipitation in July. On the basis of the three standardized chronologies the series of annual minimum temperature in Boertala from 1576 to 2002 was reconstructed. Considering the hysteresis of tree growth against temperature, a av- erage annual minimum temperature series was well reconstructed and its explain variance was 60.7 %. Test- ed by the Leave-One-Out Method it was verified that the reconstructed temperature series was reliable. The temperature change in the 427 years showed obvious vibration periods of 2-3 years and 40-50 years, and has experienced abrupt change in 1631,1832,1920,1961.