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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Oxygen isotopes in tree rings are a good proxy for Amazon precipitation and El Nino-Southern Oscillation variability
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Oxygen isotopes in tree rings are a good proxy for Amazon precipitation and El Nino-Southern Oscillation variability

机译：年轮中的氧同位素很好地替代了亚马逊地区的降水和厄尔尼诺-南方涛动变化

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摘要

We present a unique proxy for the reconstruction of variation in precipitation over the Amazon: oxygen isotope ratios in annual rings in tropical cedar (Cedrela odorata). A century-long record from northern Bolivia shows that tree rings preserve the signal of oxygen isotopes in precipitation during the wet season, with weaker influences of temperature and vapor pressure. Tree ring δ~(18)O correlates strongly with δ~(18)O in precipitation from distant stations in the center and west of the basin, and with Andean ice core δ~(18)O showing that the signal is coherent over large areas. The signal correlates most strongly with basin-wide precipitation and Amazon river discharge. We attribute the strength of this (negative) correlation mainly to the cumulative rainout processes of oxygen isotopes (Rayleigh distillation) in air parcels during westward transport across the basin. We further find a clear signature of the El Nino-Southern Oscillation (ENSO) in the record, with strong ENSO influences over recent decades, but weaker influence from 1925 to 1975 indicating decadal scale variation in the controls on the hydrological cycle. The record exhibits a significant increase in δ~(18)O over the 20th century consistent with increases in Andean δ~(18)O ice core and lake records, which we tentatively attribute to increased water vapor transport into the basin. Taking these data together, our record reveals a fresh path to diagnose and improve our understanding of variation and trends of the hydrological cycle of the world's largest river catchment.
机译：我们提出了一个独特的代理来重建亚马逊地区降水变化的重建：热带雪松（Cedrela odorata）年轮中的氧同位素比。来自玻利维亚北部的长达一个世纪的记录表明，树木年轮在潮湿季节保留了降水中氧同位素的信号，而温度和蒸气压的影响较小。树环δ〜（18）O与盆地中部和西部遥远站点的降水中的δ〜（18）O密切相关，与安第斯冰芯δ〜（18）O密切相关，表明信号在大范围内是相干的地区。该信号与流域范围内的降水和亚马逊河流量最相关。我们将这种（负）相关性的强度主要归因于整个盆地向西运输过程中，空气包裹中的氧同位素（瑞利蒸馏）的累积降雨过程。我们在记录中进一步发现了厄尔尼诺-南方涛动（ENSO）的明显特征，近几十年来对ENSO的影响很大，但从1925年至1975年的影响较弱，这表明水文循环控制的年代尺度变化。该记录显示出20世纪δ〜（18）O的显着增加，与安第斯山脉δ〜（18）O冰芯和湖泊记录的增加一致，我们将其归因于水蒸气向盆地中传输的增加。综合这些数据，我们的记录揭示了一条诊断和提高我们对世界上最大的河流流域水文周期变化和趋势的理解的新途径。

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    Roel J. W. Brienen; Gerd Helle; Thijs L. Pons; Jean-Loup Guyot; Manuel Gloor;

  • 作者单位

    Department of Ecology and Global Change, School of Geography, University of Leeds, Leeds LS2 9JT, United Kingdom,Department of Plant Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, 3508 TB Utrecht, The Netherlands;

    Helmholtz Centre Potsdam, German Research Centre for Geosciences, Department of Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473 Potsdam, Germany;

    Department of Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3508 TB Utrecht, The Netherlands;

    Institut de Recherche pour le Developpement, Lima, Peru;

    Department of Ecology and Global Change, School of Geography, University of Leeds, Leeds LS2 9JT, United Kingdom;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
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  • 关键词

    climate change; dendrochronology; plant physiology;

    机译：气候变化;树木年代学植物生理学;

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