Martin Léo C P, Blard Pierre-Henri, Lavé Jérôme, Condom Thomas, Prémaillon Mélody, Jomelli Vincent, Brunstein Daniel, Lupker Maarten, Charreau Julien, Mariotti Véronique, Tibari Bouchaïb, Davy Emmanuel
Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS-Université de Lorraine, 54500 Vandœuvre-lès-Nancy, France.
Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway.
Sci Adv. 2018 Aug 29;4(8):eaar2514. doi: 10.1126/sciadv.aar2514. eCollection 2018 Aug.
Heinrich events are characterized by worldwide climate modifications. Over the Altiplano endorheic basin (high tropical Andes), the second half of Heinrich Stadial 1 (HS1a) was coeval with the highstand of the giant paleolake Tauca. However, the atmospheric mechanisms underlying this wet event are still unknown at the regional to global scale. We use cosmic-ray exposure ages of glacial landforms to reconstruct the spatial variability in the equilibrium line altitude of the HS1a Altiplano glaciers. By combining glacier and lake modeling, we reconstruct a precipitation map for the HS1a period. Our results show that paleoprecipitation mainly increased along the Eastern Cordillera, whereas the southwestern region of the basin remained relatively dry. This pattern indicates a southward expansion of the easterlies, which is interpreted as being a consequence of a southward shift of the Bolivian High. The results provide a new understanding of atmospheric teleconnections during HS1 and of rainfall redistribution in a changing climate.
海因里希事件的特征是全球气候发生变化。在阿尔蒂普拉诺内流盆地（热带安第斯山脉高处），海因里希冰期1后半段（HS1a）与巨型古陶卡湖的高水位期同时出现。然而，在区域到全球尺度上，这一湿润事件背后的大气机制仍然未知。我们利用冰川地貌的宇宙射线暴露年龄来重建HS1a阿尔蒂普拉诺冰川平衡线高度的空间变异性。通过结合冰川和湖泊模型，我们重建了HS1a时期的降水图。我们的结果表明，古降水量主要沿着东科迪勒拉山脉增加，而盆地的西南部地区仍然相对干燥。这种模式表明东风带向南扩张，这被解释为是玻利维亚高压向南移动的结果。这些结果为HS1期间的大气遥相关以及气候变化中的降雨再分配提供了新的认识。
