SA41B-2352
MTeX: The Mesosphere-Lower Thermosphere Turbulence Experiment
Thursday, 17 December 2015
Poster Hall (Moscone South)
Richard L Collins1, Colin Charles Triplett1, Aroh Barjatya2, Gerald A Lehmacher3, David C Fritts4, Franz-Josef Luebken5, Boris Strelnikov6 and Michael J Nicolls7, (1)University of Alaska Fairbanks, Fairbanks, AK, United States, (2)Embry-Riddle Aeronautical University, Physics and Astronomy, Daytona Beach, FL, United States, (3)Clemson University, Clemson, SC, United States, (4)GATS, Inc., Newport News, VA, United States, (5)University of Rostock, Leibniz Institute of Atmospheric Physics, Kühlungsborn, United States, (6)Leibniz Institute of Atmospheric Physics, Kühlungsborn, Germany, (7)SRI International Menlo Park, Menlo Park, CA, United States
Abstract:
The Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX) is a rocket-based experiment that was conducted on the night of the 25-26 January 2015 at Poker Flat Research Range (PFRR), Chatanika, Alaska (65°N, 147°W). The experiment required two key elements: the ability to measure turbulence in well-defined meteorological conditions and the ability to measure fluctuations in the atmosphere at sub-meter scales. Modern lidar (or laser radar) systems provided the first element. Rocket-borne ionization gauges and ionization probes provided the second element. We used the established rocket launching and lidar facilities at PFRR to study this turbulence. The specific weather condition we required to frame our turbulence measurement was a Mesospheric Inversion Layer. MILs are a signature of large-scale planetary wave breaking in the upper atmosphere, where a region with a temperature inversion lies below a region with an adiabatic lapse rate. The region with the inversion allows small-scale waves to become unstable, break, and generate turbulence. The region with the adiabatic lapse rate is indicative of a well-mixed layer and the presence of turbulence. The Rayleigh lidar observations began at 18:37 25 January local time. By 20:30 we had acquired sufficient lidar signal to detect a MIL between 80-85 km. The first MTeX rocket was launched at 00:13 and the second one at 00:46. The lidar temperature soundings show that the atmosphere was disturbed with temperatures in the stratosphere being cooler than expected from climatology with no clear stratopause. Our preliminary analysis of the rocket measurements shows spectral characteristics typical of layers of strong turbulence. Measurements were made both on the upleg and downleg of each rocket flight. In this presentation we present the technical details of the rocket flight, key data from the flight, and show how that data from different instruments is combined to characterize the waves and turbulence present during MTeX. The documentation of the MIL and the weather conditions over the whole night critically define the model scenarios for characterizing and understanding the turbulence using contemporary fluid-dynamic computer simulations.
