西藏热玛沟流域冰川型泥石流历史的树木年代学重建  

Dendrochronological Interpretation of Glacial Debris Flow History in the Rema Gully,Xizang,China

作　　者：徐文君 马超[1] 吕立群 杜翠 XU Wenjun;MA Chao;LYU Liqun;DU Cui(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;School of Software Engineering,Chengdu University of Information Technology,Chengdu 610225,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]成都信息工程大学软件工程学院,成都610225

出　　处：《山地学报》2025年第1期122-131,共10页Mountain Research

基　　金：第二次青藏高原综合科学考察(2019QZKK0902)。

摘　　要：树木年代学方法因其强连续性和高分辨率特性,广泛应用于泥石流灾害历史重建。然而,传统树木年代学方法在对特定区域树种及其生境特征进行参数化处理时存在不足,基于生长释放/抑制机制的年轮分析方法在不同区域的适用性受到限制。喜马拉雅山脉中段地区是冰川泥石流多发区。该区域尚未开展基于树木年代学方法的泥石流重建灾害历史研究。本文以喜马拉雅山脉中段吉隆藏布江流域热玛沟为研究对象,通过解剖学分析47棵树平均树龄(82 a±24 a)的创伤特征(树脂道密度≥12个/cm^(2)),结合重建泥石流暴发时间的精确度(R=0.8)动态优化生长扰动阈值;分析树木年轮因泥石流干扰产生的伤疤、愈伤组织及生长释放/抑制等特征,结合区域树木生长特征,优化了树木年轮生长释放/抑制的阈值和W it指数(加权响应指数)的计算方法,重建研究区的泥石流灾害历史;结合遥感影像解译数据,验证其适用性。结果表明:(1)热玛沟流域树木年轮弱生长释放/抑制阈值修正为25%(原标准40%),强生长释放/抑制阈值修正为54%(原标准60%),事件识别准确率提升至87.6%(p<0.01)。通过1988-2022年的遥感影像解译,成功识别出10场泥石流事件(1991年、1995年、1999年、2002年、2006年、2010年、2014年、2015年、2016年、2017年),其时空分布特征与实地调查匹配度达91.4%。这证明了新的生长释放/抑制阈值和W it指数计算方法在精准定灾方面的有效性。(2)首次重建出1943年和1968年两次历史强泥石流事件,将热玛沟流域灾害序列回溯期扩展至75 a。(3)传统阈值标准会造成约40%的泥石流事件漏判,改进后的双阈值体系显著提升灾害识别精度(Kappa系数0.82),这为冰川活跃区的泥石流灾害研究提供了新的视角和方法论支持。本研究建立的树木年代学新方法为冰川活跃区泥石流灾害的精准识别提供了新的技术手段,对完善�Dendrochronology,with its exceptional time-continuity and high-resolution characteristics,has been widely applied in reconstructing geo-disaster histories.However,dendrochronology method has insufficiency in parameterizing the characteristics of trees and their habitats in a specific area,which limits the applicability of region-specific tree-ring analysis based on growth release/suppression mechanisms.The mid-Himalayas,a glaciated debris flow-prone area,it lacked of studies on debris flow reconstruction using dendrochronology.In this paper,it took the Rema Gully in the Gyirong Tsangpo River basin of the mid-Himalayas as the study area.Through anatomical analysis of trauma features(resin duct density≥12 per cm^(2))in 47 trees(mean age 82±24 years)and dynamic optimization of growth disturbance thresholds using the precision of reconstructed debris flow occurrence times(R=0.8),it developed an enhanced methodology for determining growth release/suppression thresholds and calculating the Disaster Disturbance Index(W it).This approach integrated tree scars,callus tissues,and growth responses induced by debris flow disturbances with regional tree growth patterns to reconstruct the Gully's debris flow history,validated through remote sensing interpretation.(1)The optimized thresholds significantly improved event identification accuracy to 87.6%(p<0.01),with weak growth release/suppression threshold adjusted to 25%(original 40%)and strong threshold to 54%(original 60%).Remote sensing validation(1988-2022)confirmed 10 debris flow events(1991,1995,1999,2002,2006,2010,2014,2015,2016,2017)showing 91.4%spatiotemporal consistency with field surveys,demonstrating the method's effectiveness.(2)Two previously undocumented major historical events in 1943 and 1968 were reconstructed,extending the disaster chronology to 75 years.(3)Traditional thresholds underestimated approximately 40%of events,while the improved dual-threshold(weak/strong)system achieved significantly higher identification accuracy(Kappa coefficient=0.82),provi

关 键 词：树木年代学 冰川型泥石流 生长释放/抑制 灾害重建 热玛沟 

分 类 号：P642[天文地球—工程地质学] X43[天文地球—地质矿产勘探]