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

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

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?

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

GV KingAir

DateIOPGV RF# LegsW range (m/s) King Air March *Y March *Y April Y April Y April Y April *Y Six “Track B” Sierra Wave events in T-Rex (* larger waves)

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

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

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

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

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

MF versus Z Note flux reversal.

Equipartition

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

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

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

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

Parcel displacement