Atmospheric Coupling via Energetic Particle Precipitation (EPP)

Cora Randall

University of Colorado Laboratory for Atmospheric and Space Physics Department of Atmospheric and Oceanic Sciences

Cora Randall, CEDAR Meeting, 25 June 2010 Acknowledgments

Scott Bailey Laura Holt Chuck Bardeen Charles Jackman Xiaohua Fang Dan Marsh Jeff France Mike Mills Lynn Harvey David Siskind

ACE, SABER, HALOE Science Teams

NASA, NSF

Cora Randall, CEDAR Meeting, 25 June 2010 Vertical Coupling ● Troposphere to thermosphere ● In the polar region ● Mainly in winter

Outline Introduction Historical Results Recent Anomalies Outstanding ???

Cora Randall, CEDAR Meeting, 25 June 2010 Energetic Particle Precipitation

Medium & High Energy Electrons

Solar Protons

Adapted from Lean, 1994

Cora Randall, CEDAR Meeting, 25 June 2010 Solar-Magnetosphere Energy Energetic Particle Low-energy particles precipitate in thermosphere Precipitation (EPP) ↓↓↓ NO transported High-energy Ionization & downward and/or particles precipitate produced locally in mesosphere and Dissociation stratosphere ↓↓↓ POLAR VORTEX NOx and HOx

NOx and HOx Destroy Ozone

Cora Randall, CEDAR Meeting, 25 June 2010 Why talk about EPP effects on stratospheric ozone in a turbopause workshop?

NO produced in the auroral region near 100 km or higher can be transported to the stratosphere, where it participates in ozone destruction

Understanding NO transport through the turbopause is thus critical to understanding the effects of EPP on the stratosphere

Cora Randall, CEDAR Meeting, 25 June 2010 EPP Effects on the Stratosphere

Cora Randall, CEDAR Meeting, 25 June 2010 EPP Indirect Effect NO produced in mesosphere or thermosphere and descends to stratosphere

Routine production, but MLT NOx has lifetime of days, so stratospheric effects require efficient downward transport − Polar night − Strong descent in MLT − Confinement in Polar Vortex

NOx in stratosphere destroys ozone

Cora Randall, CEDAR Meeting, 25 June 2010 First satellite observations of EPP Indirect Effect from LIMS in NH, 1978-1979

EPP is the ONLY source of mesospheric

NOx in the polar winter!

Based on Russell et al., 1984

Cora Randall, CEDAR Meeting, 25 June 2010 Satellite observations of EPP-NOx were sparse from 1979 to 2003. EPP Investigations mainly used solar occultation data from SAGE, HALOE, and POAM ● Sparse geographic coverage

● SAGE & POAM only measure NO2, not NO ● No polar night

In 2003 more data became available e.g., GOMOS, MIPAS, SCIAMACHY, ACE-FTS ● Many observations of IE

● Local stratospheric NOx increases up to 4x

● Accompanying O3 decreases up to 60% ● Do not measure NO in MLT in polar night

Cora Randall, CEDAR Meeting, 25 June 2010 EPP-NOx entering the Southern Hemisphere stratosphere

How significant is Adapted from Randall et al., this? JGR 2007 Up to 10% of total SH NOy (rest from N2O oxidation)

Up to 40% of

polar NOy

What determines the interannual variability?

Cora Randall, CEDAR Meeting, 25 June 2010 Indirect Effect correlates with Ap Index in SH AdaptedRandallfrom 2007JGR al., et

Variability determined by EPP-NOx production Stable Dynamics!

Cora Randall, CEDAR Meeting, 25 June 2010 Indirect Effect does not correlate with Ap Index in NH

Vortex

Fraction

Variations in production and dynamics

2001-2002: SPE 2003-2004: EPP+Met 2005-2006: Met

Cora Randall, CEDAR Meeting, 25 June 2010 NORTH ACE NOx 2004 – 2009 SOUTH

Less than average EPP – just auroral production!

Less than average EPP – just auroral production!

Randall et al., 2009 Cora Randall, CEDAR Meeting, 25 June 2010 NORTH SABER & ACE Polar Temp SOUTH

Highly elevated!

Highly elevated!

Highly elevated! Elevated Arctic stratopause in 2004, 2006, & 2009

Slightly different temperature colorCora scales; Randall, range CEDAR from Meeting, ~170K-270K 25 June 2010 (blue-red). Phenomenology

● Elevated stratopause indicative of enhanced descent in (normal) mesosphere region (adiabatic compression).

● Enhanced descent brings down more EPP-NOx.

● More efficient transport leads to large stratospheric EPP IE even when EPP itself is well below average.

What is the mechanism? Begins with extraordinary sudden stratospheric warming (strong and persistent; Manney et al., 2005; 2008; 2009)...

Cora Randall, CEDAR Meeting, 25 June 2010 The Mechanism

1. Stratospheric Warming: Equator-to-pole T gradient reverses → Zonal wind reverses direction

2. Planetary waves cannot propagate upward so upper stratosphere & lower mesosphere cool

3. Causes reformation of very strong upper vortex and westerly winds 4. Gravity waves with westward phase speed preferentially propagate to the mesosphere

5. Mesospheric westerly zonal wind slows → induces poleward meridional wind to balance pressure gradient & Coriolis

6. Leads to enhanced descent in the polar mesosphere

– Brings down more NOx – Adiabatic compression results in elevated stratopause

[Hauchecorne et al., 2007; Siskind et al., 2007; Sahishkumar & Sridharan, 2009; Winick et al., 2009]

Cora Randall, CEDAR Meeting, 25 June 2010 Why did we get such impressive stratospheric warmings and recovery in 2004, 2006, & 2009 ? We don’t know.

Maybe climate change, but still speculative

● Although 2004, 2006, and 2009 were highly unusual, the frequency of SSW seems to be increasing (~1 per year since 1999, twice as frequent as in previous half-century)

● Models predict more variability with climate change, so extremes might occur more often

● Models inconclusive with regard to frequency & strength of SSWs, but predict stronger Brewer-Dobson circulation

Cora Randall, CEDAR Meeting, 25 June 2010 Some Questions

● What is NOx really doing in the polar night?

● What mechanisms control transport of EPP-NOx in the turbopause region?

● Are coupling processes from the surface to the MLT changing (more favorable for enhanced EPP-NOx descent)?

● Is there feedback between EPP and the coupling? Thanks very much!

Cora Randall, CEDAR Meeting, 25 June 2010 References Codrescu et al., 1997 Codrescu, M.V., T.J. Fuller-Rowell, R.G. Roble, and D.S. Evans, Medium energy particle precipitation influences on the mesosphere and lower thermosphere, J. Geophys. Res. 102, 19,977-19,987, 1997.

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Garcia et al., 2007 Garcia, R.R., D.R. Marsh, D.E. Kinnison, B.A. Boville, and F. Sassi, Simulation of secular trends in the middle atmosphere, 1950-2003, J. Geophys. Res. 112, D09301, doi:10.1029/2006JD007485, 2007.

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Hauchecorne, A., et al., Large increase of NO2 in the north polar mesosphere in January-February 2004: Evidence of a dynamical origin from GOMOS/ENVISAT and SABER/TIMED data, Geophys. Res. Lett. 34, L03810, doi:10.1029/2006GL027628, 2007.

Lopez-Puertas et al., 2005 López-Puertas, M., et al., Observation of NOx enhancement and ozone depletion in the Northern and Southern Hemispheres after the October–November 2003 solar proton events, J. Geophys. Res. 110, A09S43, doi:10.1029/2005JA011050, 2005.

Manney et al., 2005 Manney, G. L., K. Kruger, J. L. Sabutis, S. A. Sena, and S. Pawson , The remarkable 2003–2004 winter and other recent warm winters in the Arctic stratosphere since the late 1990s, J. Geophys. Res. 110, D04107, doi:10.1029/2004JD005367, 2005.

Manney et al., 2008 Manney, G.L., et al., The evolution of the stratopause during the 2006 major warming: Satellite data and assimilated meteorological analyses, J. Geophys. Res. 113, D11115, doi:10.1029/2007JD009097, 2008.

Cora Randall, CEDAR Meeting, 25 June 2010 Manney et al., 2009 Manney, G.L., et al., Aura Microwave Limb Sounder observations of dynamics and transport during the record-breaking 2009 Arctic stratospheric major warming, Geophys. Res. Lett., 36, L12815, doi:10.1029/2009GL038586, 2009.

Randall et al., 1998 Randall, C.E., D. W. Rusch, R. M. Bevilacqua, K. W. Hoppel, and J. D. Lumpe, Polar Ozone and Aerosol Measurement (POAM) II stratospheric NO2, 1993– 1996, J. Geophys. Res., 103, 28,361– 28,371, 1998.

Randall et al., 2001

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Randall et al., 2006

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Randall et al., 2009

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Cora Randall, CEDAR Meeting, 25 June 2010 Rozanov et al., 2005 Rozanov, E., L. Callis,

M. Schlesinger, F. Yang, N. Andronova, and V. Zubov (2005), Atmospheric response to NOy source due to energetic electron precipitation, Geophys. Res. Lett., 32, L14811, doi:10.1029/2005GL023041

Russell et al., 1984

Russell, J.M., III, S. Solomon, L.L. Gordley, E.E. Remsberg, and L.B. Callis, The Variability of stratospheric and mesospheric NO2 in the polar winter night observed by LIMS, J. Geophys. Res. 89 (D5), 7267-7275, 1984.

Sahishkumar & Sridharan, 2009 Sathishkumar, S., and S. Sridharan (2009), Planetary and gravity waves in the mesosphere and lower thermosphere region over Tirunelveli (8.7°N, 77.8°E) during stratospheric warming events, Geophys. Res. Lett., 36, L07806, doi:10.1029/2008GL037081.

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Siskind et al., 2007 Siskind, D.E., S.D. Eckermann, L. Coy, J.P. McCormack, and C.E. Randall, On recent interannual variability of the Arctic winter mesosphere: Implications for tracer descent, Geophys. Res. Lett. 34, L09806, doi:10.1029/2007GL029293, 2007.

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Cora Randall, CEDAR Meeting, 25 June 2010