TSAP软件和COFECHA软件交叉定年差异研究——以长白山阔叶红松林优势树种红松为例

Cross-dating Differences between COFECHA and TSAP:A Case Study in Korean Pine of Changbai Mountain

【目的】为分析TSAP和COFCHA两种软件交叉定年结果差异性,检验TSAP交叉定年结果的可靠性。【方法】本文以长白山北坡阔叶红松林85个红松树芯样本为例,从交叉定年结果,年表特征及其与气候因子的响应关系等方面进行研究。【结果】COFECHA软件和TSAP软件得到的样本年龄基本一致,但两种方法保留的样本量及样本序列的相关系数存在显著差异。TSAP过程中保留75个红松样本,相关系数接近阈值水平(平均Glk值为69.7,平均CDI值为31.7);COFECHA过程保留了56个样本,样本间相关系数较高,达到0.580,且22个通过TSAP检验的样本被COFECHA剔除。COFECHA和TSAP软件保留的样本建立的年表特征及其与气候因子的关系也有所不同。COFECHA保留的样本对气候变化更为敏感,与当年7月降水显著正相关(P<0.05)。由TSAP软件交叉定年保留的样本建立的年表具有较高的信噪比,但与温度和降水的相关关系均未达到显著性水平。【结论】TSAP软件交叉定年能够达到确定样芯年龄的目的,但由于该软件检验生长趋势同步性的阈值较低,可能导致保留样本建立的年表虽然具有较高信噪比,却不能很好反映树木生长的限制因子。因此,基于保留的样本序列进行气候重建等相关研究时应选取COFECHA软件进行交叉定年,以保证样本间具有较高的一致性,提高重建序列的可靠性。

Obj ective The purpose of the study was to compare the cross-dating between TSAP and COFECHA software and to check the reliability of TSAP.[Method]Eigth-five tree core samples of Pinus koraiensis in the Changbai mountain were selected to compare the cross-dating results of two software based on cross-dating descriptions,characteristics of chronologies and their responses to climate.[Results]The age of tree core samples determined by COFECHA and TSAP was similar but there were significant differences in amount and correlation of retained sam-ples.Seventy-five of 85 samples were retained by TSAP software with a mean Glk value of 69. 7.The mean CDI value was 3 1. 7 ,which was close to the threshold.Fifty-six samples were retained by COFECHA with a mean correlation coefficient of 0. 580,meaning high correlation.Twenty-two samples retained in TSAP were removed by COFECHA process.The characteristics of residualchronologies developed by retained samples partially differed in COFECHA and TSAP.The residualchronology from COFECHA was more sensitive to climate and significantly positive withprecipitation in July （P 〈0.05）.There were no significant correlations between the residual chronologyfrom TSAP and temperature or precipitation.[Conclusion]The age of core sample couldbe determined by TSAP.Because the value of control thresholds of testing cross-dating was low,the chronology developed by the saved samples from TSAP could have high SNR but little informationin limited factor.Therefore,COFECHA should be used for cross-dating in order to ensureconsistency of time series and improve reliability of reconstruction.