Collaborative Research: P2C2--Evaluating the Origins of Multidecadal Variability in Late Holocene Indian Summer Monsoon Rainfall in Nepal

研究小组的目标是对尼泊尔印度夏季风(ISM)的降雨量进行重复的、4000年长的、精确测年的、亚十年分辨的、多代理的石笋重建，并将这一记录与气候模型模拟结合起来，以研究晚全新世不同气候状态下数十年季风变化的性质和来源。ISM提供了南亚年降水量的近70%，是该地区农业和包括冰川在内的各种自然环境的主要水资源。在过去的一个半世纪里，ISM降雨量在数十年的时间尺度上与北大西洋的海面温度呈正相关。然而，在过去的二十年里，这种联系似乎被打破了，尽管北大西洋变暖了，但印度的季风降雨量并没有增加。这一转变对区域生态系统和生活在南亚的大约20亿人产生了深远的影响。潜在的更广泛的影响包括更深入地了解影响大型人口中心的气候学系统，能力建设和与国际同事的专业知识交流，对参与研究的学生的支持，以及公众出行。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The research team aims to develop a replicated, 4000-year-long, precisely dated, sub-decadally resolved, multi-proxy stalagmite reconstruction of Indian Summer Monsoon (ISM) rainfall in Nepal and to couple this record with climate model simulations to examine the nature and origins of multidecadal monsoon variability during different climate states of the late Holocene. The ISM supplies nearly seventy percent of South Asia’s annual precipitation, serving as the primary water resource for agriculture and the myriad of natural environments, including glaciers, across the region. Over the last century and a half, ISM rainfall has been positively correlated at multidecadal time scales with sea surface temperatures in the North Atlantic Ocean. However, in the last twenty years, this link appears to have been broken, with monsoon rainfall over India failing to increase despite a much warmer North Atlantic. This shift has profound consequences for regional ecosystems and the approximately two billion people living in South Asia. The potential Broader Impacts include a deeper understanding of a climatological system which impacts large human population centers, capacity building and expertise exchange with international colleagues, support of students involved with the research, and public outreach.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.