EAGER: Pedogenic Carbonates Record Insolation Driven Surface Melting in Antarctica

EAGER：成土碳酸盐记录了南极洲日照驱动的表面融化

• 批准号: 2423761
• 负责人: Terrence Blackburn
• 金额: $ 29.91万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-10-01 至 2026-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2423761&HistoricalAwards=false
• 关键词: EAGER; Pedogenic; Carbonates; Record; Insolation

Non-technical abstractEarth’s climatic changes have been recorded in the ice core collected from the Antarctic ice sheet. While these records provide a high resolution view of how polar temperatures changed through time, it is not always clear what Earth process influence Antarctic climate. One likely contributor to Antarctic temperature changes is the cyclic changes in Earth’s orientation as it orbits the sun. These so-called Milankovitch cycles control the amount and pattern of sunlight reaching the polar regions, that in turn result in periods of climatic warming or cooling. While the orbital variations and control on incoming solar energy remain well understood, how they influence Antarctic climate remains unresolved. It is the goal of this project to determine how variations in Earth’s orbit may be locally influencing Antarctic temperatures. The researchers on this project are pursing this goal by identifying periods of past ice melting on the surface of Antarctica using minerals that precipitate from the meltwaters that resulted from past warm periods. The timing of this past melting will be determined by radioisotopic dating of the minerals using the natural radioactive decay of uranium to thorium. By dating numerous samples, collected in past scientific expeditions throughout the Antarctic continent, these researchers aim to reconstruct the frequency and spatial pattern of past warming and in doing so, determine what aspect of Earth’s orbital variations influences Antarctic ice loss.Technical abstractAntarctic ice cores provide high resolution records of Pleistocene Southern Hemisphere temperatures that show an overall coherence with Northern Hemisphere temperature variations. One explanation for this bi-hemispheric temperature covariance relies on changes in atmospheric CO2 that result from varying northern hemisphere insolation. An alternative posits that the apparent coherence of polar temperatures is due to the misleading covariance between northern hemisphere summer insolation and, the southern hemisphere summer duration. At present there is an insufficient understanding of the role that local insolation plays in Antarctic climate. The goal of this research project is to identify the temporal spatial patterns of solar forcing in Antarctica. To reach this goal, the project team will: 1) develop a way to identify periods of past surface melt production in Antarctica using U-Th dating of pedogenic carbonates; and 2) utilize the evidence of past surface melting to calibrate energy balance models and interrogate past Antarctic surface temperatures and; 3) compare the timing of Antarctic warm periods to potential solar forcing mechanisms such as peak summer insolation or summer duration. A means of identifying the spatial and temporal pattern at which local insolation influences Antarctic temperature would provide a transformative solution to the contradiction in current climate records.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.

非技术抽象的气候变化已记录在从南极冰盖收集的冰芯中。尽管这些记录提供了高度分辨率的观点，即极性温度如何随着时间的流逝而变化，但并不总是清楚地球过程会影响南极气候。南极温度变化的一个可能是一个可能的原因是地球方向的循环变化在绕太阳绕而变化。这些所谓的Milankovitch循环控制着到达极地区域的阳光的数量和模式，这又导致了杂交变暖或冷却的时期。虽然轨道变化和对传入太阳能的控制仍然充分了解，但它们如何影响南极气候仍未解决。该项目的目的是确定地球轨道中的变化如何对南极温度产生影响。该项目的研究人员通过使用从过去温暖时期造成的熔融水中沉淀出来的矿物质来确定过去冰融化的时期，从而追求这一目标。过去熔化的时机将通过使用铀自然放射性腐烂到th的矿物质来确定矿物的放射性分析。通过在整个南极大陆的过去科学探险中收集的许多样本，这些研究人员旨在重建过去变暖的频率和空间模式，并在此过程中确定地球轨道变化的哪个方面会影响南极冰损失。技术抽象的冰核可与北半部的高分辨率相结合，以表明北半部的高分辨率，以表明北半部的高分辨率，以至于北半部的高度降低了温度下的温度下降。变化。这种双半球温度协方差的一种解释依赖于由于北半球绝缘层而导致的大气二氧化碳的变化。另一种认为，极性温度的明显连贯性是由于北半球夏季隔离与南半球夏季持续时间之间的误导协方差所致。目前，人们对局部注射在南极气候中所起的作用的了解不足。该研究项目的目的是确定南极洲太阳能强迫的暂时空间模式。为了实现这一目标，项目团队将：1）开发一种方法，使用u-th u-th of the tate ded of the Attarcica识别过去的表面熔体生产周期； 2）利用过去表面熔化的证据来校准能量平衡模型，并询问过去的南极表面温度和； 3）将南极温暖时期的时间与潜在的太阳能强迫机制（例如夏季隔离或夏季持续时间）进行比较。确定局部隔离影响南极温度的空间和临时模式的一种方法，将为当前气候记录中的矛盾提供一种变革性的解决方案。该奖项反映了NSF的法定任务，并通过使用基金会的智力优点和更广泛的影响审查标准来评估通过评估来诚实地支持支持。