Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125;Biodiversity and Climate Research Centre (BiK-F) and Senckenberg Gesellschaft für Naturforschung, D-60325 Frankfurt, Germany;
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125;
Proc Natl Acad Sci U S A. 2014 Jul 1;111(26):9402-6. doi: 10.1073/pnas.1323585111. Epub 2014 Jun 16.
The Indo-Pacific Warm Pool (IPWP) is a key site for the global hydrologic cycle, and modern observations indicate that both the Indian Ocean Zonal Mode (IOZM) and the El Niño Southern Oscillation exert strong influence on its regional hydrologic characteristics. Detailed insight into the natural range of IPWP dynamics and underlying climate mechanisms is, however, limited by the spatial and temporal coverage of climate data. In particular, long-term (multimillennial) precipitation patterns of the western IPWP, a key location for IOZM dynamics, are poorly understood. To help rectify this, we have reconstructed rainfall changes over Northwest Sumatra (western IPWP, Indian Ocean) throughout the past 24,000 y based on the stable hydrogen and carbon isotopic compositions (δD and δ(13)C, respectively) of terrestrial plant waxes. As a general feature of western IPWP hydrology, our data suggest similar rainfall amounts during the Last Glacial Maximum and the Holocene, contradicting previous claims that precipitation increased across the IPWP in response to deglacial changes in sea level and/or the position of the Intertropical Convergence Zone. We attribute this discrepancy to regional differences in topography and different responses to glacioeustatically forced changes in coastline position within the continental IPWP. During the Holocene, our data indicate considerable variations in rainfall amount. Comparison of our isotope time series to paleoclimate records from the Indian Ocean realm reveals previously unrecognized fluctuations of the Indian Ocean precipitation dipole during the Holocene, indicating that oscillations of the IOZM mean state have been a constituent of western IPWP rainfall over the past ten thousand years.
印度-太平洋暖池（IPWP）是全球水文循环的关键站点，现代观测表明，印度洋纬向模态（IOZM）和厄尔尼诺-南方涛动（ENSO）对其区域水文特征都有强烈影响。然而，对 IPWP 动力学自然范围和潜在气候机制的详细了解受到气候数据的时空覆盖范围的限制。特别是，对 IOZM 动力学关键位置的西 IPWP（印度洋洋域西部）的长期（多千年）降水模式了解甚少。为了帮助纠正这一问题，我们根据陆生植物蜡的稳定氢和碳同位素组成（分别为 δD 和 δ(13)C）重建了过去 24,000 年来西北苏门答腊（西 IPWP，印度洋）的降雨变化。作为西 IPWP 水文学的一般特征，我们的数据表明在末次冰期最大值和全新世期间降雨量相似，这与先前的说法相矛盾，即由于海平面和/或热带辐合带位置的冰川消长变化，整个 IPWP 的降水增加。我们将这种差异归因于地形的区域差异以及对大陆 IPWP 海岸线位置因冰量变化而产生的不同响应。在全新世期间，我们的数据表明降雨量有相当大的变化。将我们的同位素时间序列与印度洋领域的古气候记录进行比较，揭示了全新世期间印度洋降水偶极子的先前未被认识到的波动，这表明 IOZM 平均状态的振荡一直是过去一万年来西 IPWP 降雨的组成部分。
