Collaborative Research: Constraining African Climate Since the Last Glacial Maximum via Integrated Climate and Proxy System Modeling

合作研究：通过综合气候和代理系统建模限制末次盛冰期以来的非洲气候

• 批准号: 1903348
• 负责人: James Russell
• 金额: $ 7.85万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1903348&HistoricalAwards=false
• 关键词: Collaborative; Research; Constraining; African; Climate

Earth surface temperatures in the tropics are an important factor in the global climate system because they directly influence atmospheric water vapor content and heat transport towards the poles. Widely accepted global climate models predict that tropical Africa will warm by 5 degrees Celsius (9 degrees Fahrenheit) in the coming century and these changes are expected to have both regional and global consequences. This research project will provide an important perspective on these predictions from past regional climate histories by evaluating the performance of model simulations of past temperatures based on lake sediment proxy records. The researchers will develop a new proxy system model for use by the scientific community and host webinars to educate and train users on the model. The project will support research opportunities that will reach historically underrepresented groups through programs such as the Girl Scouts of America, Research Experiences for Undergraduates at Rice University and Significant Opportunities in Atmospheric Research and Science at University Corporation for Atmospheric Research, as well as an undergraduate research opportunity at Brown University.Current understanding of past temperature history in the tropics has improved in recent decades with advances in proxies for lake temperature from geochemical records preserved in lake sediment cores. However, these lake sediment proxies fundamentally record lake temperature, while climate models primarily simulate air temperature and other Earth surface variables. This collaborative project will help bridge the gap between the lake proxy records of past climates and global climate models to bolster understanding of the controls on Earth surface temperature. The researchers will create new geochemical proxies from existing lake sediment cores, synthesize regional proxy records from tropical Africa and develop a proxy system model to translate between climate model outputs and recorded lake temperature proxies. This proxy-model comparison will be used to evaluate the patterns, rates, sensitivity and mechanisms of temperature changes in tropical Africa since the Last Glacial Maximum approximately 21,000 years ago. Specifically, the researchers will 1) analyze records of tropical African temperature to determine regional patterns, rates, and amplitudes of past temperature variability; 2) Use a new proxy system model (PSM) for lake archives to quantify the impacts of proxy-system processes on the reconstructions; 3) Use output from paleoclimate model simulations to simulate lake temperatures and proxy uncertainties with the PSM; 4) Compare African lake and air temperatures predicted by the PSM and the Paleoclimate Modelling Intercomparison Project (PMIP 3 & 4) simulations of the LGM, the mid-Holocene (6 kyr BP), and the pre-industrial, and in transient climate simulations of the past 21 kyr to the reconstructions; 5) Test the sensitivity of African temperature changes to orbital, greenhouse gas, and ice-sheet forcing in single-forcing transient simulations, and investigate mechanisms for these changes.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.

热带地区的地面表面温度是全球气候系统的重要因素，因为它们直接影响大气水蒸气含量和向杆的热传递。广泛接受的全球气候模型预测，热带非洲将在未来世纪摄入5度（华氏9度），预计这些变化将带来区域和全球后果。 该研究项目将通过评估基于湖泊沉积物代理记录的过去温度模型的表现来对过去区域气候历史的这些预测提供一个重要的观点。研究人员将开发一个新的代理系统模型，用于科学界的使用，并主持网络研讨会，以对模型进行教育和培训用户。该项目将支持研究机会，这些研究机会将通过诸如美国女童子军，莱斯大学的大学生的研究经验以及大学大气研究和科学领域的大气研究和科学领域的大量机会以及布朗大学的大学生研究机会的大气研究和科学领域的大量机会以及在最近的数十年中列入Propece speeces speeces corvers corvers corvers corvers corpers neverce corke corpers corex speece conders corpers neverce corege sedies corece corect corece corects corege corech coreg severce corect corege corpeip的研究和科学的大量研究经验都在莱克（Geage）上进行了改善。但是，这些湖泊沉积物从根本上记录了湖泊温度，而气候模型主要模拟空气温度和其他地面变量。 这个协作项目将有助于弥合过去气候的湖泊代理记录与全球气候模型之间的差距，以增强对地球表面温度控制的控制。 研究人员将从现有的湖泊沉积物核心创建新的地球化学代理，合成来自热带非洲的区域代理记录，并开发一个代理系统模型，以在气候模型输出和记录的湖泊温度代理之间转换。自大约21，000年前的最后一次冰川最大值以来，这种代理模型比较将用于评估热带非洲温度变化的模式，速率，敏感性和机制。具体而言，研究人员将1）分析热带非洲温度的记录，以确定过去温度差异的区域模式，速率和幅度； 2）使用新的代理系统模型（PSM）进行湖泊档案，以量化代理系统过程对重建的影响； 3）使用古气候模型模拟的输出来模拟PSM的湖泊温度和代理不确定性； 4）比较PSM和古气候建模对比计划（PMIP 3和4）的非洲湖泊和空气温度的模拟，在过去21 kyr to Sustructuctions的LGM，中循环（6 kyr bp）和工业前和工业前的瞬时气候模拟中； 5）测试非洲温度变化对轨道，温室气体和冰期瞬态模拟中强迫的敏感性，并研究这些变化的机制。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来支持的。

项目成果

Evaluating global temperature calibrations for lacustrine branched GDGTs: Seasonal variability, paleoclimate implications, and future directions

• DOI: 10.1016/j.quascirev.2023.108124
• 发表时间: 2023-06
• 期刊: Quaternary Science Reviews
• 影响因子: 4
• 作者: Boyang Zhao;J. Russell;V. Tsai;A. Blaus;M. Parish;Jie Liang;A. Wilk;Xiaojing Du;M. Bush

The dynamics of warming during the last deglaciation in high-elevation regions of Eastern Equatorial Africa

• DOI: 10.1016/j.quascirev.2022.107416
• 发表时间: 2022-02-23
• 期刊: QUATERNARY SCIENCE REVIEWS
• 影响因子: 4
• 作者: Garelick, Sloane;Russell, James;Marshall, Charlie
• 通讯作者: Marshall, Charlie