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

帕里什9627771 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拟议项目旨在解决的古气候研究的循环。 这个问题在研究古生代气候时最为严重，因为那时大陆的位置可能还不太清楚。古气候学家利用现有的古地理重建，好像它们独立于古气候数据，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。 拟议研究的目的是：（1）记录和评估使用古气候数据定位大陆所产生的问题，包括定位的非唯一性和使用基于纬向气候的概率曲线定位可能具有非纬向气候的大陆等问题：（2）建立更严格的采样程序，以便在古地理和古气候重建中使用古气候数据。 为了解决采样的问题，这不是指如何收集数据，而是指如何将它们编译用于空间格式，我们将开发一种新的网格系统，更适合于在经纬度网格的球体上网格化数据，该网格系统具有不均匀的网格单元尺寸。 然后，我们将制定程序，报告分布的古气候指标。 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学中一个长期存在的问题，即冈瓦纳古陆在晚泥盆世的位置。 一个可能的结果是，我们将能够根据对数据的客观评估，消除一个拟议的职位。 更可能的结果是，我们将展示必须在哪里收集新数据，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影响将是加强更严格的古地理重建，证明错误引入的循环使用古气候建模古地理重建，至少部分基于古气候指标，并建议程序，可能会克服古地理学家和古气候学家的需求之间的基本冲突。

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.