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Life and times in the early Paleogene hot-house: Using global models to reconstruct a lost paradise.

机译：古近纪早期温室中的生活和时代：使用全局模型重建失落的天堂。

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摘要

This dissertation focuses on the general warm climate of the early Paleogene (50--60Ma), and more specifically on the rapid warming that marks the geologic record at the Paleocene-Eocene (P/E) boundary (∼55Ma). The primary aim of this research is to use global climate models (GCMs) in connection with a dynamic global vegetation model (DGVM) to examine the sensitivity of the early Paleogene climate and ecosystem to changes in atmospheric greenhouse gas concentrations.; The first part of this study focuses on reconciling the large range in estimates for paleo-pCO2 from proxy data for the early Eocene. Comparisons between proxy climate estimates from Eocene fossil flora and model output from a CO2 sensitivity study with an atmosphere and land GCM coupled to a sea ice and a slab ocean model suggest that CO2 must have been high (∼1000ppm) in order to support the warm climate flora found at high latitudes during this time. While this sensitivity study does not specifically consider the warming at the P/E boundary, it does have implications for this event. The relative increases in global mean temperature with increasing CO2 suggest that if the warming across the P/E boundary were due to CO2 alone, CO2 must have increased by 500--1500ppm.; The second part of this study uses a DGVM to explore how the flora of the early Paleogene may have responded to a warming such as that at P/E boundary. Neglecting the physiological effects of CO2 on vegetation, model results suggest that warming due to an increase in CO2 of 560ppm has the greatest effect on high latitude vegetation. Results also suggest that the prescribed vegetation used in previous modeling studies of this time period is not necessarily appropriate for the modeled climates. Given the relative infancy of DGVMs compared with GCMs, this dissertation also explores the utility of DGVMs in paleoclimate research through a series of short experiments. Model output from these experiments indicates that further modeling studies of paleo-vegetation should carefully consider the physiological effects of CO2 on vegetation, as well as the influence of model input, specifically soil composition, on the modeled global distribution of vegetation.
机译：本文主要研究古近纪早期的一般温暖气候（50--60Ma），更具体地说，是标志着古新世-始新世（P / E）边界（〜55Ma）地质记录的快速升温。该研究的主要目的是将全球气候模型（GCM）与动态全球植被模型（DGVM）结合使用，以检验早期古近代气候和生态系统对大气温室气体浓度变化的敏感性。本研究的第一部分着重于调和早期始新世的代用资料对古pCO2估算值的较大范围。来自始新世化石植物群的代理气候估计值与大气和陆地GCM结合海冰和平板海洋模型的CO2敏感性研究的模型输出之间的比较表明，为了支持温暖，CO2必须很高（〜1000ppm）在此期间在高纬度地区发现的气候植物区系。尽管此敏感性研究没有专门考虑P / E边界处的变暖，但确实对这一事件有影响。全球平均温度随CO2的增加而相对增加表明，如果P / E边界上的变暖是仅由CO2引起的，则CO2必须增加500--1500ppm。这项研究的第二部分使用DGVM来探索古近纪早期植物区系可能对诸如P / E边界变暖的反应。忽略了CO2对植被的生理影响，模型结果表明，由于CO2增加560ppm而导致的变暖对高纬度植被的影响最大。结果还表明，该时间段以前的建模研究中使用的规定植被不一定适合建模的气候。鉴于DGVM与GCM相比还处于起步阶段，本文还通过一系列简短的实验探索了DGVM在古气候研究中的实用性。这些实验的模型输出表明，进一步的古植被建模研究应仔细考虑CO2对植被的生理影响，以及模型输入（尤其是土壤成分）对建模的全球植被分布的影响。

著录项

  • 作者

    Shellito, Lucinda J.;

  • 作者单位

    University of California, Santa Cruz.;

  • 授予单位 University of California, Santa Cruz.;
  • 学科 Paleoecology.; Physics Atmospheric Science.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 192 p.
  • 总页数 192
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 古生物学;大气科学（气象学）;
  • 关键词

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