Observations of Reduced Turbulence and Wave Activity in the Arctic Middle Atmosphere Following the January 2015 Sudden Stratospheric Warming

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Triplett, Colin C., Li, Jintai, Collins, Richard L., Lehmacher, Gerald A., Barjatya, Aroh, Fritts, David C., Strelnikov, Boris, Luebken, Franz-Josef, Thurairajah, Brentha, Harvey, V. Lynn, Hampton, Donald L., Varney, Roger H.
• Other Authors: Center for Space Science and Engineering Research (Space@VT)
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Turbulence; gravity waves; SSW; ion-gauge; lidar; Arctic; Alaska
• Online Access: http://hdl.handle.net/10919/93499; https://doi.org/10.1029/2018JD028788

Measurements of turbulence and waves were made as part of the Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX) on the night of 25-26 January 2015 at Poker Flat Research Range, Chatanika, Alaska (65 degrees N, 147 degrees W). Rocket-borne ionization gauge measurements revealed turbulence in the 70- to 88-km altitude region with energy dissipation rates between 0.1 and 24mW/kg with an average value of 2.6mW/kg. The eddy diffusion coefficient varied between 0.3 and 134m(2)/s with an average value of 10m(2)/s. Turbulence was detected around mesospheric inversion layers (MILs) in both the topside and bottomside of the MILs. These low levels of turbulence were measured after a minor sudden stratospheric warming when the circulation continued to be disturbed by planetary waves and winds remained weak in the stratosphere and mesosphere. Ground-based lidar measurements characterized the ensemble of inertia-gravity waves and monochromatic gravity waves. The ensemble of inertia-gravity waves had a specific potential energy of 0.8J/kg over the 40- to 50-km altitude region, one of the lowest values recorded at Chatanika. The turbulence measurements coincided with the overturning of a 2.5-hr monochromatic gravity wave in a depth of 3 km at 85km. The energy dissipation rates were estimated to be 3mW/kg for the ensemble of waves and 18mW/kg for the monochromatic wave. The MTeX observations reveal low levels of turbulence associated with low levels of gravity wave activity. In the light of other Arctic observations and model studies, these observations suggest that there may be reduced turbulence during disturbed winters. Plain Language Summary Turbulence remains an outstanding challenge in understanding coupling, energetics, and dynamics of the atmosphere. However, turbulence is recognized as a critical component in our models of terrestrial and space weather. Obtaining routine and accurate measurements of turbulence continues to be a major challenge. We present new rocket-borne measurements of turbulence in January ...