Boundary Layer Meteorology in a Terrestrial Meteorite Impact Crater

C. David Whiteman

Research Professor

Meteorology Department, University of Utah

Salt Lake City

A month-long meteorological field experiment was conducted at Meteor Crater near Winslow, Arizona in October 2006. The circularly symmetrical crater basin, 1.2-km wide and 165-m deep, was formed by a meteorite impact 49,000 years ago. This idealized topographic basin is a near-laboratory setting for the study of the structure and evolution of the stable boundary layer (SBL) within, above, and in the vicinity of the crater. The instrumentation for the data collection program was chosen to determine the roles of boundary layer processes on the evolution of the crater atmosphere.

The observational program was supported by in situ and remote sensing equipment and field personnel from NCAR's Earth Observing Laboratory. The data sets include observations from a radar wind profiler, 7 flux towers, a SODAR, a rawinsonde sounding system, 2 radio acoustic sounding systems, 3 tethered balloon sounding systems, 60 temperature data loggers and a network of long- and short-wave radiation sensors.

This presentation will introduce the Meteor Crater, its topographical characteristics, the goals and objectives of METCRAX 2006 (the Meteor Crater Experiment), and the observations. Results from the data analyses will focus on (a) the seasonal variation in the strength of temperature inversions that form in the crater, (b) the diurnal cycle of buildup and breakup of the cold-air pool, (c) the propagation of shadows across the crater, the asymmetries in the surface radiation and energy budgets on the different sidewalls of the crater, and their production of air temperature differences across the crater, (d) the effects of ambient winds on boundary layer evolution and on turbulent warm air break-ins on the crater sidewalls, and (e) the differences between boundary layer characteristics inside and outside the crater.