Collaborative Research: P2C2--Reconstructing South American Monsoon Sensitivity to Internal and External Forcing: Reconciling Models and Tree-ring Proxies in the Central Andes

合作研究：P2C2——重建南美季风对内部和外部强迫的敏感性：协调安第斯山脉中部的模型和树木年轮代理

• 批准号: 1703035
• 负责人: Guaciara dos Santos
• 金额: $ 6.59万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1703035&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Reconstructing; South

The potential Broader Impacts include the potential for better understanding the South American monsoon, for filling in sparse hydroclimate records, and for fuller understanding climate variability. Collaboration with South American colleagues is planned as is extensive student involvement.This project aims to employ classical dendrochronological techniques to generate new tropical tree-ring chronologies that are annually resolved and absolutely dated. Radiocarbon measurements (14-Carbon) will ensure accurate dating assessments. Thus, successful tree species will be selected to improve the 14-Carbon curve for the Southern Hemisphere. The resulting tree-ring series will be used to reconstruct past climate variability and regional to large--scale atmospheric dynamics for the last several centuries. The specific aims of the project are to improve understanding of: (1) the spatiotemporal variability of the South American summer monsoon (SASM); (2) long-term interactions between El Niño-Southern Oscillation (ENSO) and the SASM; and (3) the impact of volcanic forcing on past hydroclimate of the tropical Andes.The research aims to provide significant advances in the science of tropical dendrochronology by developing a tree-ring network for the tropical Andes in Peru and Bolivia, a region with exceedingly scarce coverage of high-resolution terrestrial paleo-records. While tree rings have been extensively used in temperate climates, the tropics remain relatively unexplored due to the difficulty, in particular, of identifying consistent wood layers (tree rings) corresponding to seasonal or annual growing periods. The Central Andes are an ideal region for overcoming these difficulties, due to the pronounced precipitation seasonality and diverse forests.The tropical Andes are a hotspot for biodiversity and its geographic position makes it extremely vulnerable to climate change. It also contains nearly all the tropical glaciers on the globe, and recent, widespread glacial retreat is causing a rapid decline in hydrological reserves. This decline, in combination with increasing water demand due to population growth and economic expansion poses an enormous challenge for water availability, biodiversity and food security. The complex topography of the Andean Cordillera leads to a climate that is characterized by strong zonal and vertical precipitation gradients. Moisture influx from the tropical Atlantic Ocean and the Amazon basin is modulated by the SASM and ENSO. The scientific understanding of this variability is challenged by the scarcity of long instrumental observations, which also limits the ability to constrain uncertainties in future climate change projections over this region.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.

潜在的更广泛影响包括更好地了解南美季风、填补稀疏的水文气候记录以及更全面地了解气候变化的潜力。计划与南美同事合作以及广泛的学生参与。该项目旨在采用经典的树木年代学技术来生成新的热带树木年轮年表，这些年表每年都会得到解决并绝对过时。放射性碳测量（14-碳）将确保准确的年代评估。因此，将选择成功的树种来改善南半球的 14 碳曲线。由此产生的树木年轮系列将用于重建过去几个世纪的气候变化和区域到大规模的大气动力学。该项目的具体目标是提高对以下方面的认识：（1）南美夏季风（SASM）的时空变化； (2) 厄尔尼诺-南方涛动（ENSO）与SASM之间的长期相互作用； （3）火山强迫对热带安第斯山脉过去水文气候的影响。该研究旨在通过为秘鲁和玻利维亚的热带安第斯山脉开发树木年轮网络，为热带树木年代学提供重大进展，该地区高分辨率陆地古记录的覆盖范围极其稀少。虽然树木年轮已广泛用于温带气候，但热带地区仍然相对未经探索，因为特别是难以识别与季节性或年度生长周期相对应的一致木材层（树木年轮）。由于明显的降水季节性和多样化的森林，安第斯山脉中部是克服这些困难的理想地区。热带安第斯山脉是生物多样性的热点地区，其地理位置使其极易受到气候变化的影响。它还包含了地球上几乎所有的热带冰川，最近大范围的冰川退缩正在导致水文储量迅速下降。 这种下降，加上人口增长和经济扩张导致的用水需求增加，对水资源供应、生物多样性和粮食安全构成了巨大挑战。安第斯山脉复杂的地形导致其气候具有强烈的纬向和垂直降水梯度。来自热带大西洋和亚马逊盆地的水分流入受到 SASM 和 ENSO 的调节。对这种变异性的科学理解受到长期仪器观测的缺乏的挑战，这也限制了限制该地区未来气候变化预测的不确定性的能力。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力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

Radiocarbon analysis confirms annual periodicity in Cedrela odorata tree rings from the equatorial Amazon

• DOI: 10.1016/j.quageo.2020.101079
• 发表时间: 2020-06
• 期刊: Quaternary Geochronology
• 影响因子: 2.7
• 作者: G. Santos;D. Granato-Souza;A. Barbosa;R. Oelkers;L. Andreu‐Hayles

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