摘要
基于亚洲夏季风与西风的影响范围将青藏高原划分为3个研究区,通过对比湖泊沉积物中多代用指标与晚全新世火山活动、北半球温度和亚洲季风指数,探讨了2 kaBP前后高原湖泊水位下降的原因,并分析了不同区域湖泊对气候波动响应的空间差异。结果表明,青藏高原西南部湖面水位下降幅度大于西北部,更甚于高原东北部。这可能是因印度夏季风(Indian Summer Monsoon,简称ISM)强度减弱,高原西南部的湖泊更依赖于ISM降水的补给,因此对该季风所带来的水汽通量的减少更加敏感。而且,该时期的北大西洋涛动(North Atlantic Oscillation,简称NAO)的位相由负转正,使得青藏高原北部水汽辐合增强、降水偏多而南部降水偏少,进而导致高原南部湖面水位下降幅度普遍大于北部湖泊。导致青藏高原气候趋于冷干的主要原因,本文归因于该阶段厄尔尼诺(EI Niño)的加强。除此之外,该时期南半球环状模(Southern Annular Mode,简称SAM)冬夏季的不同位相也通过复杂的海气耦合过程,跨越赤道对青藏高原气候起到了降温减湿的作用。
The Tibetan Plateau(TP)was divided into three zones based on the influence of the Asian summer monsoon and the westerlies.By comparing multiple proxy indicators in sediments with late Holocene volcanic activity,the Northern Hemisphere temperatures,and the Asian monsoon index,the reasons for the decline in plateau lake levels~2 kaBP were explored and the spatial differences in lake responses to climate fluctuations in the different zones were analyzed.Results show that the decline in lake water level in the southwestern part of the TP is greater than in the northwestern part,and even greater in the northeastern TP.This may be due to the weakening in the intensity of the Indian Summer Monsoon(ISM),which made lakes in the southwestern TP more dependent on the ISM precipitation replenishment and thus more sensitive to the reduction in water vapor flux brought by the ISM.Moreover,during this period,the phase of the North Atlantic Oscillation(NAO)shifted from negative to positive,leading to the increase in water vapor convergence in the northern part of the TP with more precipitation there,while the southern part of the TP received less rainfall,resulting in a generally greater decline in water levels in the southern lakes compared to those in the north.The main cause of the climate turning to colder and drier in the TP~2 kaBP is attributed to the intensification of El Niño.In addition,the different phases of the Southern Annular Mode in winter and summer through complex ocean-atmosphere coupling processes crossing the equator,also played a role in cooling and dehumidifying the climate of the TP.
作者
王郁晗
安福元
刘向军
WANG Yuhan;AN Fuyuan;LIU Xiangjun(Key Laboratory of Tibetan Plateau Surface Processes and Ecological Conservation,Ministry of Education,Qinghai Normal University,Xining 810008,China;College of Geographic Sciences,Qinghai Normal University,Key Laboratory of Physical Geography and Environmental Processes of Qinghai Province,Xining 810008,China;Institute of Plateau Science and Sustainable Development,Beijing Normal University,People's Government of Qinghai Province,Xining 810008,China;College of Geographic Sciences and Tourism,Jiaying University,Meizhou 514015,China;Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes,Qinghai Institute of Salt Lakes,Chinese Academy of Sciences,Xining 810008,China)
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2024年第2期55-68,共14页
Marine Geology & Quaternary Geology
基金
国家自然科学基金项目“早全新世青藏高原西部湖泊剧烈扩张的机制研究”(42271010)
“格尔木河上游复杂地貌过程中物质元素风化迁移机制及其资源环境意义”(42371019)
“格尔木河流域串珠状堰塞湖形成消亡的气候机制及其与察尔汗盐湖演化的耦合关系”(41961014)
青海省盐湖地质与环境重点实验室开放基金(202102,2024-KFKT-B05)。
