Publication Abstracts

Chandler 1992

Chandler, M.A., 1992: The Early Jurassic Climate: General Circulation Model Simulations and the Paleoclimate Record. Ph.D. thesis. Columbia University.

This thesis presents the results of several general circulation model simulations of the Early Jurassic climate. The simulations were designed so that meaningful model-data comparisons could be made. The general circulation model employed was developed at the Goddard Institute for Space Studies while most paleoclimate data were provided by the Paleogeographic Atlas Project of the University of Chicago.

The first chapter presents an Early Jurassic "base" simulation, which uses detailed reconstructions of paleogeography, vegetation, and sea surface temperature as boundary condition data sets. The resulting climatology reveals an Earth 5.2°C warmer, globally, than at present and a latitudinal temperature gradient dominated by high-latitude warming (+20°C) and little tropical change (+1°C). Western Pangaea, in the low and mid-latitudes, is arid except along the Tethys coast, while eastern Pangaea, located in mid to high latitudes, experiences seasonal to year-round wet conditions. Comparisons show a good correlation between simulated results and paleoclimate data. Sensitivity experiments, which address regional exceptions, are used to investigate any model-data mismatches.

Chapters two and three discuss two important aspects of Early Jurassic climate, continental aridity and global warming. Chapter two focuses on the hydrological capabilities of the general circulation model. Since hydrologic characteristics are not simulated as accurately as radiative properties, this chapter asks: to what extent can we use general circulation models to identify arid regions and what methods are most appropriate for use in paleoclimate studies? The general circulation model's hydrologic diagnostics are evaluated, using the distribution of modern deserts and Early Jurassic paleoclimate data as validating constraints. A new method, based on general circulation model diagnostics and empirical formulae, is proposed for evaluating moisture balance.

Chapter three investigates the cause of past global warming, concentrating on the role of increased ocean heat transport. Early Jurassic simulations show that increased ocean heat transports may have been a major factor in past climates. Increased ocean heat transports create latitudinal temperature gradients that closely approximate paleoclimate data and solve the problem of tropical overheating that results from elevated atmospheric carbon dioxide. Increased carbon dioxide cannot duplicate the Jurassic climate without also including increased ocean heat transports.

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BibTeX Citation

@phdthesis{ch08200o,
  author={Chandler, M. A.},
  title={The Early Jurassic Climate: General Circulation Model Simulations and the Paleoclimate Record},
  year={1992},
  school={Columbia University},
  address={New York, N.Y.},
}

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RIS Citation

TY  - THES
ID  - ch08200o
AU  - Chandler, M. A.
PY  - 1992
BT  - The Early Jurassic Climate: General Circulation Model Simulations and the Paleoclimate Record
PB  - Columbia University
CY  - New York, N.Y.
ER  -

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