树轮记录的祁连山南-北侧过去约300年干旱对比研究  

A comparative analysis of droughts on the southern and northern sides of the Qilian Mountains recorded by tree rings over the past 300 years

作　　者：田沁花[1,2] 张同文 张永[3] 韩禄斌[3,4] 唐飞 TIAN Qinhua;ZHANG Tongwen;ZHANG Yong;HAN Lubin;TANG Fei(National Climate Centre,Beijing 100081;Institute of Desert Meteorology,China Meteorological Administration/Key Laboratory of Tree-ring Physical and Chemical Research,China Meteorological Administration/Xinjiang Key Laboratory of Tree-Ring Ecology,Ürümqi 830002,Xinjiang;Key Laboratory of Land Pattern and Simulation,Institute of Geographic Science and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]国家气候中心,北京100081 [2]中国气象局乌鲁木齐沙漠气象研究所/中国气象局树木年轮理化研究重点实验室/新疆树木年轮生态实验室,新疆乌鲁木齐830002 [3]中国科学院地理科学与资源研究所,陆地表层格局与模拟院重点实验室,北京100101 [4]中国科学院大学,北京100049

出　　处：《第四纪研究》2024年第4期882-894,共13页Quaternary Sciences

基　　金：中国沙漠气象科学研究基金项目(批准号:Sqj2022014);青藏高原地球系统基础科学中心(BSCTPES)项目(批准号:41988101);国家自然科学基金项目(批准号:41977392);国家重点研发计划项目(批准号:2019YFA0606602)共同资助。

摘　　要：我国西北降雨少、变率大、干旱频率高、灾害事件频发,给社会经济造成严重后果。随着全球变暖,深入理解不同气候背景下区域干旱差异的长时间尺度特征,有助于更好地应对区域气候风险。本研究选取祁连山南、北侧5条对降水变化敏感的树轮宽度序列,依据轮宽指数划分干旱强度等级,统计干旱年份及数量,建立极端干旱年分布图表,探讨过去约300年(1701~2005年)祁连山南、北侧极端干旱事件的年际、年代际变化规律及原因。结果显示,1714年为整个研究区的干旱年;1706年、1721年、1727年、1824年和1960年为4个样点记录的极端干旱年,反映了祁连山大尺度上一致的极端干旱事件,显然18世纪祁连山区整体干旱;但过去3个世纪(1701~2005年),南、北两侧极端干旱事件在年际、年代际变化上又存在区域差异:南侧干旱期集中于18~19世纪,表现为干-干-湿,与20世纪60年代之后西北地区的干-湿转型极为吻合,而北侧干旱期集中于18世纪和20世纪,表现为干-湿-干的变化趋势,20世纪20~30年代及90年代多次出现极端干旱记录。在10年尺度上,南侧高频干旱期为1761~1770年,北侧为1711~1720年、1721~1730年和1921~1930年,北侧干旱期略频发;在30年尺度上,南侧高频干旱期为1701~1730年和1761~1790年,北侧高频干旱期为1701~1730年和1911~1940年,其中1701~1730年为南、北一致干旱期。极端干旱事件年与厄尔尼诺-南方涛动(ENSO)和北大西洋涛动(NAO)指数的时序叠加分析初步揭示了ENSO事件对祁连山区域极端干旱的可能影响,但两者对区域干旱的影响机理仍需更多研究验证。Northwestern China experiences frequent droughts and weather disasters due to its low and variable precipitation.The Qilian Mountains(36°30′~33°28′N,93°30′~103°30′E)on the northeastern Qinghai-Tibetan plateau are a critical water resource for the Hexi Corridor oasis.Understanding the spatial and temporal variations in extreme droughts between the southern and northern sides of the Qilian Mountains is crucial for effective climate risk management,especially in the context of global warming.In this study,five precipitation-sensitive tree-ring-width series were analyzed:ZMSK(38.15°N,99.95°E;3314~3491 m a.s.l.)and QYG28(38.18°N,100.44°E;3336~3409 m a.s.l.)from the southern Qilian Mountains,and YQ(39.61°N,97.88°E;3100~3500 m a.s.l.),KL3(38.81°N,99.96°E;3000~3300 m a.s.l.),and LY(37.98°N,101.26°E;3162~3350 m a.s.l.)from the northern Qilian Mountains.Residual(RES)chronologies were developed using a cubic spline with a 50%frequency-response cut-off at 67%of the series length,covering the period from 1701 A.D.to 2005 A.D.Correlation analysis with nearby meteorological data explored the climatic implications of each chronology from the prior June to the current September and with different combinations of the monthly meteorological series.All five RES chronologies showed significant positive correlations(p<0.05)with total precipitation over a 12-month period from the previous July to the current June(p7~c6).Drought intensity levels were classified based on the ring-width index,and a distribution table of extreme drought years was created to examine inter-annual and inter-decadal patterns over the past 300 years.Superposed Epoch Analysis(SEA)was used to investigate potential causes of extreme droughts,particularly the relationship between the tree-ring index and El Niño-Southern Oscillation(ENSO)and North Atlantic Oscillation(NAO)indices.The findings revealed a universal extreme drought year in 1714 A.D.across the entire study area,with five regional extreme drought years(1706 A.D.,1721 A.D.,1727 A.D.

关 键 词：祁连山 树轮宽度指数 极端干旱事件 大气环流指数 

分 类 号：P467[天文地球—大气科学及气象学]