P2C2: High-resolution Reconstruction of the South American Monsoon History from Isotopic Proxies and Forward Modeling

南美洲夏季风（SASM）对南美洲（亚）热带具有重要的社会经济意义，为生态系统完整性和人类活动（包括农业、卫生、水电生产和许多其他社会经济目的）提供水。季风强度、开始和结束日期的逐年变化与干旱和洪水有关，并可能造成广泛的经济损失。然而，对于SASM在过去是如何变化的，以及它如何响应自然（火山或太阳）和人为（气溶胶和温室气体）扰动的变化，人们知之甚少。在这个项目中，来自纽约州立大学奥尔巴尼分校的一位科学家和他的合作者将利用秘鲁安第斯山脉奎尔卡亚冰盖的冰芯数据重建SASM过去1000年的历史，以了解更多关于自然季风变化的包皮。选择Quelccaya站点是因为几乎所有的降雪都与SASM（~85%）有关，它包含长时间，高分辨率和精确年代的冰芯记录，并且一直是长期现场气候和冰川学监测和校准计划的重点。利用这些现场数据集，结合过去一千年的同位素模型模拟，科学家们将开发一个所谓的正向模型，该模型可以重建自公元850年以来亚马逊流域上游的季风变化。由于温室气体浓度的增加，人们越来越担心未来季风特征的变化，因此，更好地了解自然季风变率及其对外部强迫的敏感性是绝对必要的。该项目的进度将会在Quelccaya部落格网站上记录。该项目还包括额外的教育方面，如培训一名研究生和一名博士后研究助理，并将该项目开发的方法和结果整合到本科和研究生课堂中。

The South American summer monsoon (SASM) is of great socio-economic relevance to (sub)tropical South America, delivering water for ecosystem integrity and human activities including agriculture, sanitation, hydropower production and many other socioeconomic purposes. Year-to-year variations in monsoon strength, onset and demise dates have been linked to drought and floods and can cause widespread economic damage. Yet little is known about how the SASM has varied in the past and how it responds to changes in natural (volcanic or solar) and man-made (aerosols and greenhouse gases) perturbations. In this project, a scientist from the State University of New York at Albany and his collaborators will reconstruct the SASM history for the past 1000 years using ice core data from the Quelccaya ice cap in the Peruvian Andes to learn more about the envelope of natural monsoon variability. The Quelccaya site was chosen because almost all snowfall is associated with the SASM (~85%), it contains a long, high-resolution and precisely-dated ice-core record, and has been the focus of long-term on-site climatologic and glaciologic monitoring and calibration programs. Using these on-site data sets, combined with isotope-enabled model simulations for the past millennium, the scientists will develop a so-called forward model that allows reconstructing monsoon variations upstream over the Amazon basin since the year 850 AD. Given the growing concerns over future changes in monsoon characteristics due to enhanced greenhouse gas concentrations, a better understanding of natural monsoon variability and its sensitivity to external forcing is absolutely essential. The project's progress will be documented on the Quelccaya blog website. The project also includes additional educational aspects such as training of a graduate student and a Postdoctoral Research Associate, and integrating methods and results developed in this project into undergraduate and graduate classrooms.