Collaborative Research: Testing the Orbital Theory of Ice Ages Through Analysis of Glacial Deposits and Numerical Modeling

合作研究：通过冰川沉积物分析和数值模拟检验冰河时代的轨道理论

• 批准号: 1263474
• 负责人: Michael Kaplan
• 金额: $ 19.49万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-15 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1263474&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; Orbital; Theory; Collaborative; Research; Testing; Orbital; Theory

This research project will examine the timing and causes of ice ages in the Southern Hemisphere and how these observed climate changes compare with those found in the Northern Hemisphere. A major question in the earth-system sciences has been ascertaining what drives different sections of Earth to switch in and out of ice age climates. This is an outstanding question that remains unresolved. The traditional Milankovitch or orbital "ice-age theory" proposes that the intensity of summer insolation received in the Northern Hemisphere paces ice ages across Earth. Measurements of the intensity of summer insolation in the Northern and Southern hemispheres have been found to be out of phase, however. If glaciers expand and retreat in similar ways around Earth at the same time, other driving mechanisms therefore must be involved, such as greenhouse gasses or a global impact of the largest ice sheets that covered the land in the Northern Hemisphere. A problem is that in the Southern Hemisphere, there is insufficient information regarding when the last cold glacial period started, how long it lasted, and when it ended. Without this information, scientists are ill-equipped to assess how well Southern Hemisphere glacial climates correspond to possible driving forces, such as changes in (orbital) solar insolation intensity, Northern Hemisphere ice sheets, and atmospheric carbon dioxide. They also are unable to assess the underlying causes of ice-age climates and to refine the Milankovitch theory. This project will focus on the collection and analyses of materials that help document how glaciers in southern South America have changed over time. The investigators will employ state-of-the-art techniques in dating glacier landforms and glacial-climate modeling. The dated paleogeography of glaciers will provide boundary conditions for experiments using models developed by the researchers and others to assess the roles and responses associated with possible climate parameters, such as temperature and precipitation ranges that are needed for an ice sheet to grow and retreat over the southern Andes.This project will provide deeper understanding of the nature and causes of ice age climates and related natural environmental processes as well as their spatial and temporal differences around the globe. The project also will provide enhanced information about natural climate states, such as the climate during the last ice age that can be used as test beds for general circulation models that simulate future change. The project will provide opportunities to enhance international research collaborations between scientists in the U.S. and Chile. Education and training opportunities will be provided for undergraduate students, and educational outreach will be pursued through collaborative relationships with the American Museum of Natural History and New York City schools.

该研究项目将检查南半球冰河时代的时间和原因，以及这些观察到的气候变化与北半球的气候变化相比。 地球系统科学中的一个主要问题是确定是什么驱动了地球不同部分以切换和离开冰河时代的气候。 这是一个尚未解决的杰出问题。传统的Milankovitch或轨道“冰河时代理论”提出，北半球在跨地球的冰上衰老的夏季日期强度。 然而，发现北半球和南半球的夏季暴发强度的测量已失相。 如果冰川同时以类似的地球方式扩展和撤退，则必须涉及其他驾驶机制，例如温室气体或覆盖北半球土地的最大冰盖的全球影响。 一个问题是，在南半球，关于上一个冷冰川时期何时开始，持续了多长时间以及何时结束的信息不足。 没有这些信息，科学家就没有足够的能力来评估南半球冰川气候与可能的驱动力相对应的程度，例如（轨道）太阳日光强度的变化，北半球冰盖和大气二氧化碳。 他们也无法评估冰年龄气候的根本原因，也无法完善米兰科维奇理论。 该项目将重点关注材料的收集和分析，以帮助记录南美南部南美洲的冰川如何随着时间的流逝而变化。 研究人员将采用最先进的技术来与冰川地面和冰川气候建模进行约会。冰川的日期古地理学将使用研究人员和其他人开发的模型为实验提供边界条件，以评估与可能的气候参数相关的角色和响应，例如温度和降水范围，冰盖在安第斯山脉南部成长和撤退所需的范围。这种项目将对冰期的自然环境和临时环境及其范围及其及其范围的环境及其及其及其及其及其及其及其及其及其相关的及其及其及其及其及其及其及其及其及其及其及其及其及其及其及其及其及其及其及其及其及其及其相关的环境的原因及其及其及其及其相关的过程。 该项目还将提供有关自然气候状态的增强信息，例如最后一个冰河时代的气候，可以用作模拟未来变化的通用循环模型的测试床。 该项目将为增强美国和智利科学家之间的国际研究合作提供机会。 将为本科生提供教育和培训机会，并通过与美国自然历史和纽约市学校的合作关系来追求教育外展。