METCRAX: The Meteor Crater Experiment A Major Scientific Experiment Studying Temperature Inversions and Gravity Waves in the Arizona Meteor Crater October 2006 What is going on down in the crater? A one-month meteorological (i.e., weather) field experiment called METCRAX (The Meteor Crater Experiment) is being conducted during October 2006 in Arizona’s Meteor Crater. During the month, meteorologists from the University of Massachusetts, Michigan State University, the University of Utah, and the National Center for Atmospheric Research will be studying the formation of atmospheric seiches (standing gravity waves) in the crater and the buildup and breakdown of temperature inversions. The field research is being supplemented by atmospheric modelling in a 3-year research program supported by the U. S. National Science Foundation. Why is this being done in the Arizona Meteor Crater? The Meteor Crater was chosen because of it’s idealized basin topography. It is relatively round and symmetrical, and not too large, which makes our study sort of like a laboratory experiment, but in the field. Previous studies have investigated temperature inversions in basins and valleys, but often these have been complicated by complex topography. We hope to simplify the problem by using the crater to achieve understanding that will provide important insights into the air pollution, transportation and other practical problems that are being experienced with temperature inversions in valleys and basins throughout the Western United States and elsewhere. Atmospheric seiches have been observed in ocean and lake basins, but never in the atmosphere. We hope that the crater will provide us with a closed basin structure where these gravity waves will form and be observed. What do you hope to find out from this experiment? The two main scientific objectives of the program are: - to determine the role that basin-scale seiches and gravity waves play in the transport and mixing in the crater - to investigate the diurnal build-up and break-up of basin cold-air pools and the associated physical and dynamical processes These objectives will be achieved through observational and modelling studies. Instrumentation Over 100 meteorological or weather instruments are deployed in and around the crater to measure many different variables including: -Temperature -Humidity -Wind -Pressure -Solar and Terrestrial Radiation In addition to our continuously running sensors, we will have 6-8 Intensive Observational Periods (IOPs) where we will take additional measurements inside the crater with tethered balloons and outside the crater with free-flying weather balloons. USGS Topographic map of Meteor Crater with instrument sites indicated as above [Needs legend] Preliminary Data Temperatures on the crater rim and crater floor (top) and temperature differences (crater rim – crater floor) during October Helicoptor transporting equipment into the crater. Preparing for the Experiment Because of the Meteor Crater’s remote location and difficulty of access, all our instrumentation had to be either hiked in, or brought in by helicopter. Over 10 tons of equipment was brought into the crater for the experiment. The scientists and technicians in the crater have received special permission to access the crater. The crater is not generally accessible to visitors. Background Photo: © John S. Shelton Sketch of phenomena in a small, closed basin with a resident cold pool (red line- in sun, blue line- in shadow). Want to know more? If you would like to know more about this research program, please visit our website at: Thanks to… We would like to thank the Barringer Crater Company and Meteor Crater Enterprises for their support and assistance with this research and educational program, which would not be possible without their cooperation and encouragement. Installing temperature sensors in the Meteor Crater.