The Meteor Crater Experiment, METCRAX 2006

A month-long meteorological field experiment is planned for October 2006 at the 1.2-km-wide, 175-m-deep Meteor Crater near Winslow, Arizona. The circularly symmetrical crater basin that was formed by a meteor impact 50,000 years ago provides a near-laboratory setting to study the structure and evolution of the stable boundary layer (SBL) within, above, and in the vicinity of the crater, including the effects of radiative and sensible heat flux divergences and slope flows on the heating and cooling of the crater's atmosphere. The uniform elevation ridgeline of the crater is expected to reduce large-scale advection into the closed basin under statically stable conditions, thus simplifying the mass and heat budgets for the atmospheric volume inside the crater.

The field measurements are designed to capture (a) the mean and turbulence characteristics of the down-slope and up-slope flows into and out of the crater, (b) the diurnal cycle of buildup and breakup of the cold-air pool, (c) the role of radiative transfer in boundary layer evolution, (d) seiches and other gravity waves, and (e) mesoscale variability of the ambient wind, which is expected to trigger seiches and waves within the basin. The observational program is being supported by in situ and remote sensing equipment from the National Center for Atmospheric Research's Earth Observing Laboratory, and will also include observations from tethered balloons, temperature data loggers and long- and short-wave radiation sensors. The observations and analyses will be supplemented with state-of-the-art Direct Numerical Simulations (DNS), Large Eddy Simulations (LES), and mesoscale model simulations. The proposed investigations are expected to provide additional information on stable boundary layers in topographically confined areas and may have important practical benefits for weather prediction, air quality and frost forecasting, and agricultural meteorology

The oral presentation will introduce the Meteor Crater and its topographical characteristics, outline the goals and objectives of the METCRAX meteorological experiments, present some initial planning data and modeling results, and provide an overview of the instrumentation to be used and the experimental results to be expected.