Interpreting Paleoclimate when Continental Positions are Uncertain: the Effects of Sampling, Modeling and Reconstructing

当大陆位置不确定时解释古气候：采样、建模和重建的影响

• 批准号: 9627771
• 负责人: Judith Parrish
• 金额: $ 7.76万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-15 至 1999-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9627771&HistoricalAwards=false
• 关键词: Interpreting; Paleoclimate; when; Continental; Positions

Parrish 9627771 Paleogeographers and paleoclimatologists have tended to have very different agendas in studying paleoclimates, and their differing approaches and interests have led to a circularity in paleoclimatic studies that the proposed project is intended to address. The problem is greatest in studies of climates of the Paleozoic Era, when continental positions are likely to be poorly known. Paleoclimatologists have used available paleogeographic reconstructions as if they were independent of paleoclimatic data, but, in fact, some continental positions are determined at least partly from paleoclimatic data. The purpose of the proposed research is to: (1) document and evaluate the problems that arise from using paleoclimatic data to position continents, including such problems as non-uniquenessof positioning and the use of probability curves based on zonal climates for positioning continents that were likely to have had non-zonal climates: (2) establish more rigorous sampling procedures for the use of paleoclimatic data in both paleogeographic and paleoclimatic reconstruction. To address the problem of sampling, which refers not to how the data are collected but, rather, how they are compiled for use in a spatial fromat, we will develop a new grid system more appropriate for gridding data on a sphere that the latitude-longitude grid, which suffers from uneven grid-cell dimensions. We will then develop procedures for reporting the distribution of paleoclimatic indicators. This will permit evaluation of the robustness of the various assumptions that are made in this type of work. Finally, we will apply the developed methods to a persistent problem in Paleozoic paleogeography, that is, the positions of Gondwana in the Late Devonian. One possible outcome is that we will be able to eliminate one of the proposed positions, based on objectives evaluations of the data. A more likely outcome is that we will show where new data must be collected and which underlying assumptions must be examined to resolve the conflict. The broader implications of this project will be to enforce much more rigor into paleogeographic reconstructions, demonstrate the error introduced by circularity in using for paleoclimatic modeling paleogeographic reconstructions that are based at least in part on paleoclimatic indicators, and suggest procedures that might overcome the basic conflict between the needs of paleogeographers and those of paleoclimatologists.

Parrish 9627771古地理学家和古气候学家在研究古气候方面往往有非常不同的议程，他们不同的方法和兴趣导致了古气候研究的循环，这是拟议项目旨在解决的。这个问题在古生代的气候研究中最为严重，因为人们对古生代大陆的位置知之甚少。古气候学家使用现有的古地理重建，仿佛它们是独立于古气候数据的，但事实上，一些大陆的位置至少部分是由古气候数据确定的。本研究的目的是：(1)记录和评价利用古气候数据进行大陆定位所存在的问题，包括定位的非唯一性和利用基于地带性气候的概率曲线来定位可能存在非地带性气候的大陆；(2)为古地理和古气候重建中使用古气候数据建立更严格的采样程序。为了解决采样问题，这不是指如何收集数据，而是指如何将数据编译以用于空间格式，我们将开发一种新的网格系统，更适合于在纬度-经度网格上网格化数据，这受到网格单元尺寸不均匀的影响。然后，我们将制定报告古气候指标分布的程序。这将允许评估在这类工作中所做的各种假设的稳健性。最后，我们将把发展的方法应用于古生代古地理中一个长期存在的问题，即冈瓦纳在晚泥盆世的位置。一个可能的结果是，根据对数据的客观评估，我们将能够取消一个拟议的职位。更有可能的结果是，我们将显示必须在何处收集新数据，以及必须检查哪些基本假设以解决冲突。这个项目的更广泛的意义将是加强对古地理重建的严格性，证明在古气候建模古地理重建（至少部分基于古气候指标）中使用循环引入的错误，并提出可能克服古地理学家和古气候学家需求之间基本冲突的程序。