Tropical rainfall over the last two millennia: evidence for a low-latitude hydrologic seesaw.
Tropical rainfall over the last two millennia: evidence for a low-latitude hydrologic seesaw.
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DOI：
10.1038/srep45809
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发表时间：
2017-04-05
影响因子：
4.6
通讯作者：
Baldini JU
中科院分区：
文献类型：
--
作者：
Lechleitner FA;Breitenbach SF;Rehfeld K;Ridley HE;Asmerom Y;Prufer KM;Marwan N;Goswami B;Kennett DJ;Aquino VV;Polyak V;Haug GH;Eglinton TI;Baldini JU
低至中纬度半球间水文跷跷板的存在是明显的轨道和冰川间冰期的时间尺度，但它的存在，在最近的过去仍然不清楚。在这里，我们调查，从两个半球的气候代用重建的基础上，在过去的2000年中，在北方半球的热带辐合带（ITCZ）和低到中纬度遥相关的半球间相位。一个明显的特征是ITCZ在小冰期期间持续南移，直到世纪初。我们的新的复合ITCZ堆栈和北大西洋涛动（NAO）记录之间的强协变揭示了这两个天气和气候现象之间的紧密耦合在十年到百年的时间尺度。当比较两个精确的日期，高分辨率的古降雨记录从伯利兹和苏格兰时，这种关系变得最明显，表明低到中纬度的遥相关也活跃在年-十年的时间尺度。它可能是外部强迫的组合，即，太阳和火山，和内部反馈，驱动同步ITCZ和NAO的变化，通过在热带地区的能量通量扰动。
The presence of a low- to mid-latitude interhemispheric hydrologic seesaw is apparent over orbital and glacial-interglacial timescales, but its existence over the most recent past remains unclear. Here we investigate, based on climate proxy reconstructions from both hemispheres, the inter-hemispherical phasing of the Intertropical Convergence Zone (ITCZ) and the low- to mid-latitude teleconnections in the Northern Hemisphere over the past 2000 years. A clear feature is a persistent southward shift of the ITCZ during the Little Ice Age until the beginning of the 19th Century. Strong covariation between our new composite ITCZ-stack and North Atlantic Oscillation (NAO) records reveals a tight coupling between these two synoptic weather and climate phenomena over decadal-to-centennial timescales. This relationship becomes most apparent when comparing two precisely dated, high-resolution paleorainfall records from Belize and Scotland, indicating that the low- to mid-latitude teleconnection was also active over annual-decadal timescales. It is likely a combination of external forcing, i.e., solar and volcanic, and internal feedbacks, that drives the synchronous ITCZ and NAO shifts via energy flux perturbations in the tropics.