Large‐amplitude mesospheric response to an orographic wave generated over the Southern Ocean Auckland Islands (50.7°S) during the DEEPWAVE project. Issue 4 (18th February 2016)

• Record Type: Journal Article
• Authors: Pautet, P.‐D.; Taylor, M. J.; Fritts, D. C.; Bossert, K.; Williams, B. P.; Broutman, D.; Ma, J.; Eckermann, S. D.; Doyle, J. D.
• Is Part Of: Journal of geophysical research. Volume 121:Issue 4(2016)
• Page Start: 1431
• Page End: 1441
• Publication Date: 2016-02-18
• Subjects: mesospheric gravity waves -- orographic source; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2015JD024336
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: The Deep Propagating Gravity Wave Experiment (DEEPWAVE) project was conducted over New Zealand and the surrounding regions during June and July 2014, to more fully understand the generation, propagation, and effects of atmospheric gravity waves. A large suite of instruments collected data from the ground to the upper atmosphere (~100 km), with several new remote‐sensing instruments operating on board the NSF Gulfstream V (GV) research aircraft, which was the central measurement platform of the project. On 14 July, during one of the research flights (research flight 23), a spectacular event was observed as the GV flew in the lee of the sub‐Antarctic Auckland Islands (50.7°S). An apparent "ship wave" pattern was imaged in the OH layer (at ~83.5 km) by the Utah State University Advanced Mesospheric Temperature Mapper and evolved significantly over four successive passes spanning more than 4 h. The waves were associated with orographic forcing generated by relatively strong (15–20 m/s) near‐surface wind flowing over the rugged island topography. The mountain wave had an amplitude T ′ ~ 10 K, a dominant horizontal wavelength ~40 km, achieved a momentum flux exceeding 300 m 2 s −2, and eventually exhibited instability and breaking at the OH altitude. This case of deep mountain wave propagation demonstrates the potential for strong responses in the mesosphere arising from a small source under suitable propagation conditions and suggests that such cases may be more common than previously believed. Key Points: Localized orographic sources create mountain waves which can propagate as high as the mesosphere These waves carry large amount of momentum They eventually break and release this momentum in the atmosphere