P2C2: North American Monsoon Variability Using Instrumental and Tree-Ring Data

提供资金调查北美季风（NAM）的行为，作为墨西哥西北部和美国西南部的关键水分来源。 具体来说，研究人员将设计和应用新技术来开发一个针对美国西南部长期NAM变化的树木年轮网络。研究人员将使用该网络的部分宽度指数（早材和晚材），结合树木年轮的稳定碳同位素测量，重建和研究季风季节降水的长期变化，其与冬季降水的关系和北美西部的广泛干旱，以及太平洋的海洋/大气环流。 树木年轮数据还将与降尺度大气环流模式（GCM）相结合模拟，以帮助了解过去几个世纪美国西南部NAM的空间和时间特征，作为评估仪器记录和缩小GCM复制自然变异能力的基线的一种手段。更广泛的影响涉及强大的教育指导部分和同等的强大的智力部分。 这项研究将有助于支持研究生和本科生参与一个尖端的古气候项目，该项目的目标是利用树木年轮科学更好地为区域水资源规划者提供信息。

Funding is provided to investigate the behavior of the North American Monsoon (NAM) as a critical source of moisture for northwestern Mexico and the U.S. Southwest. Specifically, the researchers will design and apply new techniques to develop a tree-ring network that targets long-term NAM variability in the US Southwest. The researchers will use partial-width indices (earlywood and latewood) from this network, combined with stable-carbon isotope measurements from tree rings, to reconstruct and examine the long-term variability of monsoon season precipitation, its relation with winter precipitation and widespread droughts in western North America, and to ocean/atmosphere circulation in the Pacific Ocean. The tree-ring data will also be combined with downscaled general circulation model (GCM) simulations to help understand the spatial and temporal characteristics of the NAM in the southwestern U.S. over the last few centuries as a means of providing a baseline for assessing both the instrumental records and the skill of downscaled GCMs in replicating natural variability.The broader impacts involve a strong educational mentoring portion and an equally strong intellectual portion. The research will help support graduate and undergraduate student involvement in a cutting-edge paleoclimate project whose goal is to use tree-rings science to better inform regional water resource planners.