HAO Colloquium - Carl Bjorn Kjellstrand, Columbia University

PMC Turbo: results and analysis of gravity wave and instability dynamics in high altitude measurements of polar mesospheric clouds

PMC Turbo was a balloon-borne experiment that observed gravity wave dynamics in Polar Mesospheric Clouds (PMCs) above the Arctic. It launched from Esrange, Sweden, on July 8th, 2018, and landed in western Nunavut, Canada, on July 14th.

PMCs form an often thin and bright layer at about 82 km altitude in which brightness fluctuations reveal small scale dynamics in the upper mesosphere in polar summer. The PMC Turbo mission was designed to explore the dynamics of gravity waves and the gravity wave breaking and shear instabilities accounting for turbulence, mixing, and gravity wave energy and momentum deposition via high-resolution imaging of the dynamics over the life cycles of multiple events. These dynamics are most easily observed in the bright, remote PMC layer at very high altitudes, where spatial scales are large. Nevertheless, they reveal dynamics that occur throughout the atmosphere and in other geophysical fluids, but are unable to be easily observed and quantified elsewhere. Due to the high viscosity in the upper mesosphere, PMC Turbo imaging captured spatial scales from gravity waves with wavelengths of roughly 10-100 km, instability dynamics at scales from about 1-10 km, and fine structure the inner scale of turbulence at about 20 m.

The PMC Turbo payload included seven optical cameras and a Rayleigh backscatter lidar. The data from the experiment was retrieved from the payload in early August and analyses of the images and lidar data have been ongoing. In this presentation, C.B Kjellstrand will discuss science results from our initial analyses of PMC Turbo data.


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Wednesday, February 6, 2019 - 2:00pm to 3:00pm

Posted by Sheryl Shapiro at ext. 1567, sheryls@ucar.edu

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