IAGA: AUGUST, 2013, Merida, Mexico, PAPER J7-11 LARGE MESOPAUSE BRIGHTNESS EVENTS, OBSERVATIONS AND EXPLANATIONS Bright, wall, or large amplitude planar wave events in airglow Very bright, single planar event (but period hours, same as a medium scale gravity wave present with the same intrinsic phase speed, and horizontal alignment as the the medium scale gw present) Leading dark (cooling) followed by sharp brightening (warming) A large amplitude wave, or a large instability overturning event (billow) (note, the instability ‘surfs’ on the medium scale wave) Gary Swenson 1, Alan Liu 2, Mike Taylor 3, Dominique Pautet 3, Fabio Vargas 1, Tony Mangognia 1 1: University of Illinois 2: Embry Riddle University 3: Utah State University

Waves (AGWs) and Airglow Response WAVE Examples Aug 9, 1993 (ALOHA, Aircraft, Swenson and Espy) and August 10, 93 (ALOHA-Taylor et al.)* Aug 12, 2004, Li et al., 2005 (Maui, 22 o N)* Others observed by lidar, Maui Jan 24, 2012 (Cerro Pachon, Chile, 30 o S) Summary Large amplitude, medium scale gravity wave coupling with a large amplitude tide, for a single planar wave. Both Convective and Shear Instabilities Result

OH O 2 (b) O ( 1 S) Fig. 4 Vargas et al., Mesospheric Airglow Layers

Mesosphere, Lower Thermosphere Remote Sensing Instrumentation Andes Lidar Observatory (ALO) (Cerro Pachon, Chile, 30 o S) Na Doppler Lidar (U of I; Liu,ERAU) OH Temperature Mapper (Taylor, USU) Meteor Radar (Franke, U of I) OH, 90 o imager, 1.6μ (Hecht, Aerospace) OH, Na, O 2, O( 1 S) Allsky Imager (U of I) Multi-Channel Photometer, Zenith, OH, O 2, O( 1 S), BG (Mangognia, U of I)

August 9, 93 (ALOHA, Aircraft, Swenson and Espy)

August 10, 93 (ALOHA-Taylor et al.)* Note: Direction of propagation, and event time of the ‘wall’ of airglow was ~23.5 hours after the Aug 9 event. O2O2 OH

Analysis showed that this event was caused by a large- amplitude, upward-propagating gravity wave with a period of about 4–5 hours and a vertical wavelength of about 20 km, i.e., a ‘‘wall’’ wave. This wall wave induced dramatic changes in temperature (T’/T 30 K), airglow intensity (doubled in the OH and tripled in the O2 emissions), and Na abundance (tripled). Feng Li et al., Investigation of a ‘‘wall’’ wave event, JGR,2007 Li et al., 2005 (Maui)* (Zonal, propagated from West)

Superadiabatic Altitude (km) Temperature (K) Convective Instabilites Swenson et al., 1998 Dynamic Instabilites F. Li et al., 2005 Δt~45 min

. Large amplitude for  1 h h km,  ~1.5-7 hours Trailing, phase front aligned, hf wave And Z Inversion, dT/dz = 0 LAW zone Large Amplitude Wave Cool--Warm Dim-Bright

Other Maui Waves

MCP data O( 1 S) OH λ x = 100 km λ z = 16 km Φ = 349 ° τ o = 132 min c o = 15 m/s (from NNW) UT

Temperature Mapper Keogram OH Temperature Bright Event N-S E-W Time, UT

Summary 11/14 Event Winds, Z ~15 km,consistent with OH and O 1 S phase. 60 m/s phase speed,  AGW ~6 hr wave; h = 1300 km Events--Common features: Z (and phase speeds)-Similar, km. All source directions from NW or W* All events have downward phase progression below T inversion h varies-300 to 1300 km, + trailing SS waves All have one, large magnitude, ~1 h leading feature Upwelling then downwelling T, cold then warm; Airglow dim then bright Thickness of the ‘enhanced’ wave 4-8 km. 01/24/2012 Cerro Pachon Event, Forced instabilities, a surfing billow?

Wall Waves Spatial x= km, y= 1000’s km, z=5-10 km Temperature T, 30K cooling, followed by warming AGW couples with tide to force instability Large scale, well capable of bubble scale Observed in mesopause region ( km) Predicted for next tidal VWL, i.e km In Northern Hemisphere, propagate from NW-SE Observe and study with ICON Readily observed along the phase front T profiles from km Plot T separately from both FOV of Mighty