Description and Initial Results

Eugene S. Takle[1,2,3], William J. Gutowski, Jr.[1,2], Raymond W. Arritt[2],
aitao Pan[2], Christopher J. Anderson[2], Renato Ramos da Silva[2], Daniel Caya[9],
Shyh-Chin Chen[8], Jens Hesselbjerg Christensen[5], Song-You Hong[7],
Hann-Ming Henry Juang[7], Jack Katzfey[4], William M. Lapenta[6],
Rene Laprise[9], Philippe Lopez[5], John McGregor[4], John O. Roads[8]

1 Department of Geological and Atmospheric Sciences, Iowa State University, Ames.
2 Department of Agronomy, Iowa State University, Ames.
3 International Institute of Theoretical and Applied Physics, Iowa State University, Ames.
4 Commonwealth Scientific and Industrial Research Organisation, Mordialloc, Australia.
5 Danish Meteorological Institute, Copenhagen, Denmark.
6 Marshall Space Flight Center, Huntsville, Alabama.
7 National Centers for Environmental Prediction, Camp Springs, Maryland.
8 Scripps Institute of Oceanography, La Jolla, California.
9 Universite du Quebec a Montreal, Canada.

August 1998
Submitted to
Journal of Geophysical Research

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ABSTRACT

A description is given for the first simulation experiment and output archives of the Project to Intercompare Regional Climate Simulations (PIRCS). Initial results from simulations of the summer 1988 drought over the central U.S. indicate that limited-area models forced by large-scale information at the lateral boundaries are able to reproduce bulk temporal and spatial characteristics of meteorological fields. In particular, the 500 hPa height field's time average and temporal variability are generally well simulated by all participating models.

Model simulations of precipitation episodes vary depending on the scale of the relevant dynamical forcing. Organized synoptic-scale precipitation systems are simulated deterministically in that precipitation occurs at close to the same time and location as observed (though the amounts may vary from the observations). Episodes of mesoscale and convective precipitation are represented in a more stochastic sense, with less precise agreement in temporal and spatial patterns.

Simulated surface energy fluxes near the FIFE region show broad similarity with FIFE observations in their temporal evolution and time average diurnal cycle. Inter-model differences in mid-day Bowen ratio tend to be closely associated with precipitation differences. Differences in daily maximum temperatures are also linked to the Bowen ratio differences, indicating strong local, surface influence on this field. Although some of the models have bias with respect to the FIFE observations, they all tend to reproduce the synoptic variability of observed daily maximum and minimum temperatures.