Collaborative Research: P2C2: Reconstructing Holocene Climate Change in the Southern Hemisphere from Southern Alps Mountain Glaciers and Tree Rings

合作研究：P2C2：从南阿尔卑斯山冰川和树木年轮重建南半球全新世气候变化

• 批准号: 1903220
• 负责人: Aaron Putnam
• 金额: $ 41.88万
• 依托单位: University of Maine
• 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 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1903220&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Reconstructing; Holocene

A major objective of climate science is to evaluate ongoing planetary warming within the context of past natural variations of the climate system, such as the well-known Little Ice Age and Dark Ages cold periods, and Medieval and Roman warm periods, as well as warmer-than-present conditions in some regions registered during the early Holocene, about 8,000 to 10,000 years ago. These past climatic anomalies are best documented from the Northern Hemisphere; thus, it is not clear whether they constituted global fluctuations in the atmospheric heat budget or if they were regional in nature. This question has fundamental implications for understanding the underlying drivers of natural climate variability, and for determining whether industrial-age warming has yet exceeded the envelope of climate variability registered over the past 10,000 years. This project establishes the record of Holocene climate variations, based on glaciers and temperature-sensitive trees, in the Southern Alps of New Zealand - on the opposite side of the planet from the North Atlantic region. Mountain glaciers are among Earth's most sensitive climate recorders on timescales of decades and longer. Worldwide recession of mountain glaciers is an iconic illustration of global warming. Glacial landforms afford physical evidence of past glacier extent, and this effort will employ state-of-the-art cosmogenic dating techniques on those landforms to establish precise and accurate chronologies of glacier changes during and prior to the period of recorded observations. This work incorporates tree-ring chronologies of temperature-sensitive South Island species that afford continuous records of climatic fluctuations on annual timescales. Altogether, chronologies of glacier extent and tree growth will be used to develop a comprehensive record of past temperature variation in the Southern Alps for comparison to equivalent records in the Northern Hemisphere. The resultant temperature reconstruction will also provide a key metric for evaluating a suite of global climate and earth-system models developed by the National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory, some of which are now being used for weather forecasting by the National Weather Service. This effort will afford field-based educational experiences for the next generation of scientists and science journalists. A goal of paleoclimate research is to understand patterns and drivers of natural climate variations during the Holocene. Documentation of natural climate variability on orbital, centennial, and shorter frequencies provides a contextual framework for modeling ongoing and future warming due to the effects of increasing atmospheric CO2. The most recent major natural climatic variations in the North Atlantic regime prior to the ongoing warming were those of the Roman Warm Period (~250 B.C. to ~A.D. 400), Dark Ages Cold Period (~A.D. 450 to ~A.D. 950), Medieval Warm Period (~A.D. 950 to ~A.D. 1150) and the Little Ice Age (~A.D. 1150 to ~A.D. 1850). These late-Holocene temperature variations are documented by highly resolved records of glacier-length variation in the European Alps, as well as independent, annually resolved tree-ring-based regional summer temperature reconstructions. In addition, European glaciers monitored a period of reduced ice extent during the early Holocene at the same time as tree-line altitudes were higher. Both observations signify summers that were warmer than those of today. But it is not yet clear whether these climate signatures were global or regional in scope; thus, the underlying mechanisms remain uncertain. This work will address this problem by developing a precise 10Be surface-exposure chronology of moraines constructed by glaciers during the Holocene in the Southern Alps of New Zealand - on the opposite side of the planet from the European Alps. The researchers will also develop chronology of Holocene ice retraction by 14C dating recently deglaciated organic remains. Investigators employ a well-calibrated glaciological model to convert these moraine chronologies into a glacier-derived record of temperature over the past two millennia. The proposed glacier chronology will be synthesized with an independent and complementary record of regional summer temperatures for the past 2000 years derived from South Island silver pine ring widths. The glacier and tree-ring records will be used as benchmarks to investigate results from the GFDL ESM2M preindustrial climate simulations. On the basis of this glacier, dendro, and modeling approach, the goal of this work is to determine whether Holocene climate variations were global or not, and therefore improve understanding of underlying drivers and the scope of natural climate variability in light of ongoing planetary warming.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.

气候科学的一个主要目的是在气候系统的过去自然变化的背景下评估正在进行的行星变暖，例如众所周知的小冰河时代和黑暗时代，中世纪和罗马温暖的时期，以及在早期早期注册的某些地区，大约8,000至10，000年前，在某些地区，大约是较温暖的地区。这些过去的气候异常最好记录在北半球。因此，尚不清楚它们是否构成大气热预算中的全球波动，还是本质上是区域性的。这个问题对理解自然气候变异性的潜在驱动因素具有根本的影响，并确定工业年龄变暖是否超过了过去10，000年来注册的气候变异性信封。该项目建立了新西兰南部阿尔卑斯山南部阿尔卑斯山的全新世气候变化的记录 - 与北大西洋地区的地球另一侧。在数十年且更长的时间尺度上，山地冰川是地球最敏感的气候录音机之一。山冰川的全球衰退是全球变暖的标志性例证。冰川地面提供了过去冰川范围的物理证据，这项工作将在这些地面上采用最先进的宇宙源性约会技术，以在记录的观察结果期间和之前建立冰川变化的精确和准确的时间。这项工作结合了对温度敏感的南岛物种的树环，可在年度时间表上连续记录气候波动。总体而言，冰川范围和树木生长的时间顺序将用于制定南方南部阿尔卑斯山过去温度变化的全面记录，以与北半球的等效记录进行比较。最终的温度重建还将提供一个关键指标，以评估由国家海洋和大气管理部门地球物理流体动力学实验室开发的全球气候和地球系统模型，其中一些人现在被国家天气服务用于天气预报。这项工作将为下一代科学家和科学记者提供基于现场的教育经验。古气候研究的目的是了解全新世期间自然气候变化的模式和驱动因素。轨道，百年和较短频率上自然气候变化的文档提供了一个上下文框架，可以通过增加大气二氧化碳的影响来建模正在进行的和未来的变暖。北大西洋制度的最新主要自然气候变化是在正在进行的变暖之前（〜250公元前〜250 to 〜a.d。400），深色年龄（〜a.d。450至〜A.D. 950），Medeevem暖时期，Medeeval温暖期（〜A.D. 950至〜A.D.A.D. 1150）和冰年龄（1150年）和少量年龄（〜A.D.A.这些后新世的温度变化记录在欧洲阿尔卑斯山冰川长度变化以及独立的，每年的基于树环的区域夏季温度重建的高度分析记录中。此外，欧洲冰川在全新世早期监测了一段时间，因为树线高度较高。这两种观察都表明夏天比今天温暖。但是尚不清楚这些气候签名是全球还是区域范围。因此，基本机制仍然不确定。这项工作将通过在新西兰南部阿尔卑斯山（全新世）期间建立冰川在新西兰南部阿尔卑斯山（与欧洲阿尔卑斯山的另一侧）建立的精确的10BE表面暴露于冰川的表面暴露时间来解决这一问题。研究人员还将通过最近退化的有机遗物来开发全新世冰撤回的年表。研究人员采用良好校准的冰川学模型将这些冰or的时间顺序转换为过去两千年中冰川衍生的温度记录。拟议的冰川年表将通过过去2000年的区域夏季温度的独立和互补记录来合成，从南岛银松树环宽度衍生出来。冰川和树环记录将用作基准测试，以研究GFDL ESM2M工业化前气候模拟的结果。基于这种冰川，Dendro和建模方法，这项工作的目的是确定全新世气候变化是否全球化，因此，根据正在进行的行星变暖的持续奖励，这是NSF的法定任务，反映出值得一提的是，依据的依据是，这一奖项被认为是构成的，因此，根据正在进行的行星变暖而自然气候变化的范围。

项目成果

Correspondence Among Mid‐Latitude Glacier Equilibrium Line Altitudes, Atmospheric Temperatures, and Westerly Wind Fields

中纬度冰川平衡线高度、大气温度和西风场的对应关系

• DOI: 10.1029/2022gl099897
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Audet, Alexander C.;Putnam, Aaron E.;Russell, Joellen L.;Lorrey, Andrew;Mackintosh, Andrew;Anderson, Brian;Denton, George H.
• 通讯作者: Denton, George H.