Mountain Waves entering the Stratosphere Ronald B. Smith*, Bryan Woods*

1. Mountain Waves entering the Stratosphere Ronald B. Smith*, Bryan Woods* J. Jensen**, W. Cooper**, J. D. Doyle*** Q. Jiang***, V. Grubisic*** * *Yale University, New Haven, Connecticut ** National Center for Atmospheric Research, Boulder, CO; ***Naval Research Laboratory, Monterey, CA, ****Desert Research Institute, Reno, NV Support from the National Science Foundation Ozone data from Ilana Pollack, Andy Weinheimer

2. Approach • Mountain Wave structure and properties are expected change as the waves enter the stratosphere. • The repetitive GV racetrack flights in T-Rex provide an improved data set to study these wave changes across the tropopause. • GPS altitude adds an important new wave diagnostic tool

3. Questions • How are mountain waves modified by the tropopause and by layering and shear in the stratosphere? • Are the linear theory predictions regarding EF and MF correct? • Is there partial reflection? How can we detect it? • How do waves and layering interact? • Is there evidence for “secondary generation” of waves? How can we detect this?

4. Outline • Flight track strategy with the GV • Wave Environments • Momentum and Energy Fluxes • Energy density diagnostics and equipartition • Conserved variable (e.g. Bernoulli and Ozone) layering in the stratosphere

6. GV KingAir

7. Six “Track B” Sierra Wave events in T-Rex (* larger waves)

8. Soundings for three “large wave” Track B flights WD~245T

9. The racetrack pattern, coupled with GPS altitude, allows the geostrophic wind to be estimated. Each point is a racetrack from one of the six Track-B flights. Ageostrophy may be due to streamline curvature

10. Wave Diagnostic Equations Energy and Momentum Fluxes Energy Density Equipartition Ratio : PE/(KEZ+KEH) Bernoulli Function (steady, perfect gas) Z = GPS altitude

11. Wave advection of “conserved variables” in layering Bernoulli- corrected Crest-parallel winds

12. Each point is a leg. Note 7 reversed fluxes: All RF10 EF requires GPS altitude.

13. MF versus Z Note flux reversal.

14. Equipartition

15. Conclusions • All six Track-B events have similar soundings, including • A weakly stable layer just below the tropopause • Stable layer just above the tropopause • Critical level near 21km • The three stronger wind cases are also the three stronger wave cases. Waves are partly unsteady and not exactly 2-D. • We verified the Eliassen-Palm (1961) relationship between MF and EF, and the related linearized Bernoulli equation. MF is roughly constant with height, except for RF10. • We identified the modulation of wave energy density and equipartition associated with partial reflection at the tropopause. • We identified conserved variable layering (e.g. Bernoulli and Ozone) with scale ~ 100m in the stratosphere. This is probably related to airmass interleaving. • GPS altitude data was useful for: • Geostrophic wind • Energy flux computation • Bernoulli-corrected wind layering • Wave kinetic energy density

16. Conclusions II • Strong wave events RF4 and RF5 can be described by vertically propagating waves satisfying linear theory • Strong wave event RF10 has unique properties, perhaps caused by secondary wave generation • MF and EF fluxes reverse in the stratosphere • Trapped (no flux) short wave at the 13km • Downward propagating long wave at 13km

17. The End R.B. Smith View SW towards the Sierra Nevada Range

18. A/C photo Gulfstream V DWS High-performance Instrumented Airborne Platform for Environmental Research (HIAPER)

20. Parcel displacement