Collaborative Research: Testing Mechanisms for Holocene Climate Change in the Southern Tropical and Mid-Latitude Andes

合作研究：热带南部和中纬度安第斯山脉全新世气候变化的测试机制

• 批准号: 1003460
• 负责人: Meredith Kelly
• 金额: $ 41.31万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1003460&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; Mechanisms; Holocene

This collaborative grant is collecting paleoclimate proxy data from locations in Southern Hemisphere tropical and mid-latitudes and using these data to constrain global circulation model (GCM) simulations of climate change. Through this coordinated effort, the research enhances our knowledge of potential mechanisms which influenced Holocene climate events such as the Little Ice Age. The investigators have three specific aims: 1) developing a continuous record of Holocene climate change near the largest tropical ice mass, Peru's Quelccaya Ice Cap, using multiple paleoclimate proxies, including chironomid and diatom assemblages in lake sediments; 2) tracking Little Ice Age climatic conditions over a broader area of the Andes, from ~13 to 40°S latitude; and 3) using a GCM to evaluate which mechanistic hypotheses explain the geographical and temporal patterns of reconstructed paleoclimatic fluctuations.This research establishes a detailed multi-proxy record of the Holocene paleoclimate and paleoenvironment in the southern tropics near the Quelccaya Ice Cap. Defined by radiocarbon ages and supplemented by surface exposure (10Be) ages, this chronology is comparable with higher-latitude records from both Northern and Southern Hemispheres. In addition to the temporally detailed record from Quelccaya, the research provides a spatially resolved reconstruction of climate during the Little Ice Age in the southern tropics and mid-latitudes. The broader pattern of Little Ice Age Andean glacier fluctuations in multiple climatic regimes also provides valuable data for examining the relative influences of temperature and precipitation on such fluctuations. These efforts interface with ongoing NSF-funded research (EAR-0902363) investigating Holocene glacier fluctuations in Patagonia, enhancing both research projects.This research provides both paleoclimate proxy data and modeling results to further the understanding of Holocene and recent climate change in the southern tropics and mid-latitudes. The research tests various mechanisms for the Little Ice Age. For example, it examines results from modeling of solar forcing during the Little Ice Age which suggest that there were changes in tropical circulation in addition to Northern Hemisphere climate changes. Since the paleoclimate data from near Quelccaya Ice Cap spans a time period influenced by differing boundary conditions, such as high and low austral summer insolation, it should be possible to examine various mechanisms for rapid climate events. Possible mechanisms include a latitudinal shift of the Intertropical Convergence Zone and the strengthening/weakening of the El Niño Southern Oscillation (ENSO).The broader impacts of the research include (1) applying and evaluating a promising proxy (chironomid assemblages) method in a new area (tropical Andes) and archiving sediment cores; (2) strengthening and establishing new international and interdisciplinary collaborations among scientists including Dr. Pedro Tapia of Peru and Chilean scientists; (3) training graduate and undergraduate students; and (4) ensuring outreach and dissemination to the general public of information regarding climate change.

该协作赠款是从南半球热带和中纬度地区的位置收集古气候代理数据，并使用这些数据来限制气候变化的全球循环模型（GCM）模拟。通过这项协调的努力，这项研究增强了我们对影响全新世气候事件（例如小冰河时代）的潜在机制的了解。研究人员有三个具体的目的：1）使用多个古气候代理，包括秘鲁的Quelccaya冰盖，在最大的热带冰块附近建立一个连续的全新世气候变化记录，其中包括湖沉积物中的哲学和硅藻组合。 2）在安第斯山脉更广阔的区域上跟踪冰期气候条件很少，从约13至40°s纬度； 3）使用GCM评估哪些机械假设解释了重建的古气候波动的地理和临时模式。这项研究建立了在Quelccaya Ice Cap附近的南部热带地区，全新世古气候和古环境的详细多态记录。由放射性碳年龄定义，并补充了表面暴露（10BE）年龄，该年表与北半球和南半球的更高纬度记录相当。除了Quelccaya的暂时详细记录外，这项研究还提供了南部热带地区和中纬度冰河时代的空间解决气候的空间重建。多种民用制度中，冰河时代小的冰河时代冰川波动的更广泛的模式也为检查温度和降水对这种波动的相对影响提供了有价值的数据。这些努力与正在进行的NSF资助研究（EAR-0902363）调查了巴塔哥尼亚的全新世冰川波动，增强了这两个研究项目。这项研究提供了对古气候的代理数据和建模既提供了对南部热带和中期气候变化的了解和最近的气候变化的结果。该研究测试了小冰河时代的各种机制。例如，它检查了小冰河时期太阳能强迫建模的结果，这表明除北半球气候变化外，热带循环发生了变化。由于来自Quelccaya冰盖附近的古气候数据跨越了受不同边界条件（例如高和低澳大利亚夏季隔离）影响的时期，因此应该可以检查各种机制是否有快速气候事件。可能的机制包括在热带融合区的纬度转移以及厄尔尼诺南部振荡（ENSO）的加强/削弱。研究的更广泛影响包括（1）在新区域（热带和档案库中）应用和评估有前途的替代（ChironomId组合）方法。 （2）加强和建立新的国际和跨学科合作，包括秘鲁的Pedro Tapia博士和智利科学家； （3）培训毕业生和本科生； （4）确保向有关气候变化的信息公众推广和传播。