8B.1
Meteorological experiments in a small closed basin: New results from the Meteor Crater Experiment (METCRAX) (Invited)
C. David Whiteman, University of Utah, Salt Lake City, UT; and S. W. Hoch, M. Hahnenberger, and S. Zhong
A multi-investigator meteorological field experiment was conducted in October 2006 in Arizona's Meteor Crater, a basin in north-central Arizona that was formed from the impact of a meteorite approximately 50,000 years ago. The Meteor Crater Experiment (METCRAX) was designed to answer scientific questions about stable boundary layer evolution in an idealized basin, and new results are now coming from analyses of the extensive data set.
The Meteor Crater is a unique natural setting. The bowl-shaped crater is 1.2 km in diameter, 165 m in depth, and the nearly level rim is 40-60 m above the surrounding Colorado Plateau. The plateau itself is slightly tilted, with terrain rising to the southwest of the crater culminating in an elevated plateau region called the Mogollon Rim. The Meteor Crater is located in an arid region of the Southwest and, because the region has low rainfall and erosion, the crater itself is considered to be the best preserved meteorite crater on earth.
The talk will provide an overview of selected METCRAX results coming from analyses on four topics:
1. Diurnal evolution of the boundary layer
2. Evolution of slope flows on the crater sidewalls
3. The surface radiation and energy budgets within the crater, and
4. The influence on the crater boundary layer of ambient winds at the crater rim
On the first topic, new results are coming from analyses of asymmetries in boundary layer development during the buildup and breakdown of the stable boundary layer that forms in the crater, as well as from comparative studies of boundary layer development inside and outside the crater. On the second topic, analyses are finding weak and intermittent nighttime downslope flows on the crater sidewalls, except for a short time period following local sunset. On the third topic, analyses of high-quality, slope-parallel measurements are showing quite significant variations in radiation and energy budget components across the crater topography and an energy budget imbalance at all sites, including the sites over horizontal surfaces inside and outside the crater. On the fourth topic, a large-scale nighttime drainage flow from the Mogollon Rim interacts strongly with the developing stable layer inside the crater, and produces mix-outs and oscillations in flow over the upstream sidewall. Interestingly, the effect is often confined to the upstream sidewalls.
Recorded presentationSession 8B, Meteor Crater Experiment (METCRAX)
Thursday, 14 August 2008, 8:30 AM-10:00 AM, Fitzsimmons
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