Collaborative Research: P2C2--Reconstructing Atmospheric 14C across the Inter Tropical Convergence Zone Using Tropical Tree Rings from South America and Central Africa

合作研究：P2C2——利用南美洲和中非的热带树木年轮重建跨热带辐合带的大气 14C

• 批准号: 1903690
• 负责人: Guaciara dos Santos
• 金额: $ 28.62万
• 依托单位: University of California-Irvine
• 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: 2019-07-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1903690&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Reconstructing; Atmospheric

This project aims to develop an observational record of atmospheric radiocarbon (14C) data post-1950 by using calendrically dated tree rings across the intertropical convergence zone (ITCZ). The tree-ring sites are located in South America (Ecuador, Peru, Bolivia, Brazil) and central Africa (Cameroon) across the ITCZ band. These new 14C data will be used to constrain the spatial pattern of atmospheric 14C in the southern hemisphere, which currently relies on samples collected mostly in the eastern part of the southern hemisphere. The researchers will additionally measure the ring width and the stable isotope compositions of Oxygen and Carbon from the tree rings to investigate factors that can cause spatial and temporal variations of 14C variations. These include the seasonality of tree growth and the source of rainwater which reflects atmospheric circulation dynamics. The combined proxies aim to improve: 1) regional and local features of ITCZ circulation and inter-hemispheric exchange; 2) prediction of the ITCZ shifts in response to anthropogenic forcings; 3) the 14C calibration curve for the equatorial southern hemisphere.The potential Broader Impacts include a better definition of the intra-hemispheric 14C zonal division at lower latitudes, and the 14C timescale in Southern hemisphere which will benefit the paleoclimate community for chronology constraints (accuracy of the radiocarbon method) of the Holocene and climate dynamics of the ITCZ. Results of this project will benefit other fields including: radiocarbon calibration, astrophysics, ecology, biogeochemical and Earth science and archeology. The project will provide training for two undergraduate students and one PhD student. A radiocarbon short course will be organized at University of California Irvine where researchers, students and international collaborators will participate. The data of these project will be integrated in the International intercalibration curve of atmospheric radiocarbon.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.

该项目的目的是通过使用热带辐合带（ITCZ）上的树木年轮进行年代测定，建立1950年后大气放射性碳（14 C）数据的观测记录。树木年轮地点位于热带集水区带的南美洲（厄瓜多尔、秘鲁、玻利维亚、巴西）和中非（喀麦隆）。这些新的14 C数据将用于限制南半球大气14 C的空间格局，目前主要依赖于在南半球东部收集的样本。研究人员还将测量树木年轮的年轮宽度和氧和碳的稳定同位素组成，以调查可能导致14 C变化的空间和时间变化的因素。这些因素包括树木生长的季节性和反映大气循环动力学的雨水来源。这些综合替代指标的目的是：1）改善ITCZ环流和半球间交换的区域和局地特征; 2）预测ITCZ对人为强迫的响应; 3）赤道南半球的14 C校准曲线。潜在的更广泛影响包括更好地定义低纬度的半球内14 C分区，而南半球的14 C时间尺度将有利于古气候界对全新世年代学约束（放射性碳方法的准确性）和ITCZ的气候动力学的研究。该项目的成果将有益于其他领域，包括：放射性碳校准，天体物理学，生态学，地球化学和地球科学和考古学。该项目将为两名本科生和一名博士生提供培训。将在加州尔湾大学举办一个放射性碳短期课程，研究人员、学生和国际合作者将参加。该奖项反映了NSF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。

项目成果

A universal approach to alpha-cellulose extraction for radiocarbon analysis of 14C-free to post-bomb ages

• DOI: 10.1016/j.quageo.2022.101414
• 发表时间: 2022-11
• 期刊: Quaternary Geochronology
• 影响因子: 2.7
• 作者: G. Santos;Anita S.Y. Komatsu;Jazmine M. Renteria;A. F. Brandes;Christopher A. Leong;Silvana Collado-Fabbri;R. De Pol‐Holz

Age structure and climate sensitivity of a high Andean relict forest of Polylepis rodolfo-vasquezii in central Peru

• DOI: 10.1016/j.dendro.2023.126071
• 发表时间: 2023-03
• 期刊: Dendrochronologia
• 影响因子: 3
• 作者: G. Ticse-Otarola;Osir D. Vidal;L. Andreu‐Hayles;H. R. Quispe-Melgar;M. Amoroso;G. Santos;Edilson Jimmy Requena-Rojas

Revealing Polylepis microphylla as a suitable tree species for dendrochronology and quantitative wood anatomy in the Andean montane forests

• DOI: 10.1016/j.dendro.2022.125995
• 发表时间: 2022-08
• 期刊: Dendrochronologia
• 影响因子: 3
• 作者: C. Rodríguez-Morata;A. Pacheco-Solana;G. Ticse-Otarola;TE Boza Espinoza;DB Crispín-DelaCruz;GM Santos;M. Morales;EJ Requena-Rojas;L. Andreu‐Hayles

High-precision 14C measurements of parenchyma-rich Hymenolobium petraeum tree species confirm bomb-peak atmospheric levels and reveal local fossil-fuel CO2 emissions in the Central Amazon

对富含薄壁组织的 Hymenolobium petraeum 树种进行高精度 14C 测量，证实了大气峰值水平，并揭示了亚马逊中部当地的化石燃料二氧化碳排放量

• DOI: 10.1016/j.envres.2022.113994
• 发表时间: 2022
• 期刊: Environmental Research
• 影响因子: 8.3
• 作者: Santos, Guaciara M.;Albuquerque, Rafael Perpétuo;Barros, Cláudia Franca;Ancapichún, Santiago;Oelkers, Rose;Andreu-Hayles, Laia;de Faria, Sergio Miana;De Pol-Holz, Ricardo;das Neves Brandes, Arno Fritz
• 通讯作者: das Neves Brandes, Arno Fritz

Growth Assessment of Native Tree Species from the Southwestern Brazilian Amazonia by Post-AD 1950 14C Analysis: Implications for Tropical Dendroclimatology Studies and Atmospheric 14C Reconstructions

• DOI: 10.3390/f12091177
• 发表时间: 2021-08
• 期刊: Forests
• 影响因子: 2.9
• 作者: G. Santos;Daigard Ricardo Ortega Rodriguez;N. D. Barreto;Gabriel Assis-Pereira;A. Barbosa;F. Roig;Mário Tomazello-Filho