Collaborative Research: P2C2--Unravelling the Signals in Tropical Pacific Lake Archives: Towards Improved Holocene Hydroclimate Reconstructions

本项目旨在利用一个新的跨学科工具箱，通过将现有湖泊沉积物岩心记录与现有全球气候模式相结合，模拟大气水分输送，建立代理系统模型，解决站点间不确定性，最终提高对热带降水变率和变化的认识。全球年际降水变率的最大单一原因与厄尔尼诺-南方涛动（ENSO）现象有关。ENSO预估降水响应的幅度和方向仍存在很大的不确定性。为了了解ENSO和热带水文气候（即降水量、强度和季节性）对过去气候变化的响应，在亚马逊、安第斯和加拉帕戈斯群岛开展了大量湖泊沉积物古气候重建。然而，这些记录之间的差异使应对气候风险和极端水文气候的能力复杂化。该项目的具体目标是：(i)改进热带湖泊沉积物档案的解释，并利用高分辨率湿度跟踪模拟与综合气候模式进行代理模式比较；（ii）约束了早全新世至今热带古气候记录的敏感性；(3)将湖泊气候重建与气候模式模拟相结合，了解热带水文气候在时空尺度上的变化。潜在的更广泛的影响包括提高对全新世热带水文气候变化的幅度、时间和驱动因素的理解。该项目还将为两名早期研究人员、一名博士后、两名研究生和本科生提供支持。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project aims to use a new interdisciplinary toolbox to resolve inter-site uncertainties by synthesizing existing lake sediment cores records with existing global climate models to simulate atmospheric moisture transport, build proxy-system models, and ultimately improve the understanding of tropical precipitation variability and change.The largest single cause, globally, in interannual precipitation variability is associated with the El Nino-Southern Oscillation (ENSO) phenomenon. Large uncertainties remain regarding the magnitude and direction of the projected precipitation response with ENSO. Numerous lake sediment paleoclimate reconstructions have been developed from the Amazon, Andes, and Galapagos Archipelago with the goal of understanding the response of ENSO and tropical hydroclimate (i.e., precipitation amount, intensity, and seasonality) to past climate changes. Disagreement between these records, however, complicates the ability to prepare for climate risks and hydroclimate extremes.This project specifically aims to: (i) improve the interpretation of tropical lake sediment archives and facilitate proxy-model comparisons using high-resolution moisture tracking simulations with a comprehensive climate model; (ii) constrain the sensitivity of tropical paleo-climate records from the early-Holocene to present; and (iii) synthesize climate reconstructions from lakes with climate model simulations to understand tropical hydroclimate variability across spatial and temporal scales.The potential Broader Impacts include improved understanding of the magnitude, timing, and drivers of tropical hydroclimate variability over the Holocene. The project will also provide support for two early-career researchers, a postdoctoral fellow, two graduate students, and undergraduate students.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.