Climate model boundary conditions for four Cretaceous time slices J. O. Sewall1,*, R. S. W. van de Wal1, K. van der Zwan2, C. van Oosterhout3, H. A. Dijkstra1, and C. R. Scotese4 1Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands 2Faculty of Geosciences, P.O. Box 80021, 3508 TA Utrecht, The Netherlands 3Shell International Exploration and Production, P.O. Bos 60, 2280 Rijswijk, The Netherlands 4PALEOMAP Project, Department of Earth and Environmental Sciences, Univ. of Texas at Arlington, Texas, 76019, USA *now at: Department of Geosciences, Virgina Tech, 4044 Derring Hall (0420) Blacksburg, VA 24061, USA
Abstract. General circulation models (GCMs) are useful tools
for investigating the characteristics and dynamics of past climates.
Understanding of past climates contributes significantly to our overall
understanding of Earth's climate system. One of the most time consuming, and
often daunting, tasks facing the paleoclimate modeler, particularly those
without a geological background, is the production of surface boundary
conditions for past time periods. These boundary conditions consist of, at a
minimum, continental configurations derived from plate tectonic modeling,
topography, bathymetry, and a vegetation distribution. Typically, each
researcher develops a unique set of boundary conditions for use in their
simulations. Thus, unlike simulations of modern climate, basic assumptions in
paleo surface boundary conditions can vary from researcher to researcher.
This makes comparisons between results from multiple researchers difficult
and, thus, hinders the integration of studies across the broader community.
Unless special changes to surface conditions are warranted, researcher
dependent boundary conditions are not the most efficient way to proceed in
paleoclimate investigations. Here we present surface boundary conditions
(land-sea distribution, paleotopography, paleobathymetry, and paleovegetation
distribution) for four Cretaceous time slices (120 Ma, 110 Ma, 90 Ma, and 70 Ma).
These boundary conditions are modified from base datasets to be
appropriate for incorporation into numerical studies of Earth's climate and
are available in NetCDF format upon request from the lead author. The
land-sea distribution, bathymetry, and topography are based on the 1°×1°
(latitude × longitude) paleo Digital Elevation Models (paleoDEMs) of
Christopher Scotese. Those paleoDEMs were adjusted using the
paleogeographical reconstructions of Ronald Blakey (Northern Arizona
University) and published literature and were then modified for use in GCMs.
The paleovegetation distribution is based on published data and
reconstructions and consultation with members of the paleobotanical community
and is represented as generalized biomes that should be easily translatable
to many vegetation-modeling schemes.
Citation: Sewall, J. O., van de Wal, R. S. W., van der Zwan, K., van Oosterhout, C., Dijkstra, H. A., and Scotese, C. R.: Climate model boundary conditions for four Cretaceous time slices, Clim. Past, 3, 647-657, doi:10.5194/cp-3-647-2007, 2007.