Dynamic and Chemical Aspects of the Mesospheric Na ‘Wall’ Event on 9 October 1993 During the ALOHA Campaign

Authors

G. R. Swenson
J. Qian
J. M.C. Plane
P. J. Espy
Michael J. Taylor, Utah State UniversityFollow
D. N. Turnbull
R. P. Lowe

Document Type

Article

Journal/Book Title/Conference

Journal of Geophysical Research

Volume

103

Issue

D6

Publisher

American Geophysical Union

Publication Date

4-1998

First Page

1180

Last Page

1189

Abstract

On October 9, 1993, observations were made from the National Center for Atmospheric Research Electra aircraft during a flight from Maui, Hawaii, toward a low-pressure system NW of the island, a flight of 7 hours in total. The leading edge (wall) of a bright airglow layer was observed 900 km NW of Maui at 0815 UT, which was traveling at 75 m s−1 toward the SE, reaching Haleakala, Maui, about 3.25 hours later [see Swenson and Espy, 1995]. An intriguing feature associated with the event was the large increase in the mesospheric Na column density at the wall (∼180%). The enhancement was distributed over a broad region of altitude and was accompanied by significant perturbations in the Meinel (OH) and Na D line airglow emission intensities, as well as the temperature. This paper describes an investigation of the combined measurements from the aircraft and at Haleakala, including an analysis of the event using a gravity wave dynamic model. The modeled atmospheric variations associated with the leading edge of the “wall” wave are then applied to models of the neutral and ionic chemistry of sodium in order to establish whether the enhancement was caused by the release of atomic Na from a local reservoir species, as opposed to redistribution by horizontal convection. The most likely explanation for the Na release was the neutralization of Na+ ions in a sporadic E layer that was first transported downward by a large amplitude (≈10%) atmospheric gravity wave and then vertically mixed as the wave pushed the atmosphere into a super adiabatic state with associated convective instabilities and overturning.

Comments

Published by the American Geophysical Union in Journal of Geophysical Research.

http://www.agu.org/pubs/crossref/1998/97JD03379.shtml

Publisher PDF is available for download through the link above.

Recommended Citation

Swenson, G.R., J. Qian, J.M.C. Plane, P.J. Espy, M.J. Taylor, D.N. Turnbull, and R.P. Lowe, Dynamic and chemical aspects of the mesospheric Na ‘wall’ event on 9 October 1993 during the ALOHA campaign, J. Geophys. Res., 103, 6361, 1998.