Stratospheric imaging of polar mesospheric clouds: A new window on small‐scale atmospheric dynamics. Issue 14 (17th July 2015)

• Record Type: Journal Article
• Authors: Miller, A. D.; Fritts, D. C.; Chapman, D.; Jones, G.; Limon, M.; Araujo, D.; Didier, J.; Hillbrand, S.; Kjellstrand, C. B.; Korotkov, A.; Tucker, G.; Vinokurov, Y.; Wan, K.; Wang, L.
• Is Part Of: Geophysical research letters. Volume 42:Issue 14(2015:Jul.)
• Page Start: 6058
• Page End: 6065
• Publication Date: 2015-07-17
• Subjects: polar mesospheric clouds -- atmospheric gravity waves -- instabilities and turbulence -- energy and momentum deposition -- multiscale dynamics; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2015GL064758
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Instabilities and turbulence extending to the smallest dynamical scales play important roles in the deposition of energy and momentum by gravity waves throughout the atmosphere. However, these dynamics and their effects have been impossible to quantify to date due to lack of observational guidance. Serendipitous optical images of polar mesospheric clouds at ∼82 km obtained by star cameras aboard a cosmology experiment deployed on a stratospheric balloon provide a new observational tool, revealing instability and turbulence structures extending to spatial scales < 20 m. At 82 km, this resolution provides sensitivity extending to the smallest turbulence scale not strongly influenced by viscosity: the "inner scale" of turbulence, l 0 ∼10( ν 3 / ϵ ) 1/4 . Such images represent a new window into small‐scale dynamics that occur throughout the atmosphere but are impossible to observe in such detail at any other altitude. We present a sample of images revealing a range of dynamics features and employ numerical simulations that resolve these dynamics to guide our interpretation of several observed events. Key Points: Instabilities and turbulence play key roles in gravity wave momentum deposition New PMC imaging reveals dynamics extending to the smallest scales of turbulence New modeling helps quantify PMC imaging of instability and turbulence dynamics