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: 1138274
• 负责人: Yarrow Axford
• 金额: $ 5.54万
• 依托单位: Northwestern University
• 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: 2010-09-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1138274&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.

这项合作资助正在收集南半球热带和中纬度地区的古气候代理数据，并利用这些数据来限制全球环流模型（GCM）对气候变化的模拟。通过这种协调努力，该研究增强了我们对影响气候变化的潜在机制的了解。小冰河时代等全新世气候事件研究人员有三个具体目标：1）利用多种古气候，在最大的热带冰块秘鲁奎尔卡亚冰盖附近建立全新世气候变化的连续记录。代理，包括湖泊沉积物中的摇蚊和硅藻组合；2) 跟踪南纬 13° 至 40° 范围内安第斯山脉更广泛区域的小冰期气候条件；3) 使用 GCM 评估哪些机制假设可以解释重建古气候波动的地理和时间模式。这项研究建立了南部热带地区全新世古气候和古环境的详细多代理记录奎尔卡亚冰盖由放射性碳年龄定义并辅以表面暴露 (10Be) 年龄，该年表可与北半球和南半球的高纬度记录相媲美。除了奎尔卡亚的时间详细记录外，该研究还提供了空间记录。解决了南部热带和中纬度地区小冰期气候的重建问题，多种气候状况下小冰期安第斯冰川波动的更广泛模式也为以下方面提供了宝贵的数据。研究温度和降水对这种波动的相对影响。这些工作与正在进行的 NSF 资助的研究 (EAR-0902363) 相结合，调查巴塔哥尼亚的全新世冰川波动，增强了这两个研究项目。这项研究提供了古气候代理数据和建模结果，以进一步促进研究。对全新世和近期热带地区和中纬度地区气候变化的了解该研究测试了小冰河时期的各种机制，例如，它检查了小冰河时期太阳强迫模型的结果。冰河时代表明，除了北半球气候变化之外，热带环流也发生了变化。由于来自奎尔卡亚冰盖附近的古气候数据跨越了一个受不同边界条件（例如南半球夏季日照强度高和低）影响的时间段，因此应该是这样的。可能的机制包括热带辐合带的纬度变化和厄尔尼诺南方涛动的加强/减弱。 （ENSO）。该研究的更广泛影响包括（1）在新区域（热带安第斯山脉）应用和评估有前途的代理（摇蚊组合）方法并存档沉积物岩心；（2）加强和建立新的国际和跨学科合作；包括秘鲁佩德罗·塔皮亚博士和智利科学家在内的科学家；(3) 培训研究生和本科生；(4) 确保向公众宣传和传播有关气候变化的信息。