Challenges for Upper Atmosphere Research

ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 1

Challenges for Upper AtmosphereResearch

Erkki KyröläFinnish Meteorological Institute

ContentsMesosphere structure and features

Ozone distributionSolar proton events

NLCSummary


Atmospheric layers

Lutgens and Tarbuck's The Atmosphere, 2001

Structure and features


protonselectrons photons

Gravitywaves

Tides

Chemistry

Non-LTE Atoms, Ions

Mesospheric phenomena

Vertical transport and diffusion

Mesosphericcirculation

Emissionsmeteor dustShuttleexhaust


Temperature distribution: JanuarySources: ECMWF (z<45 km), MSIS90 (z>45 km)


Temperature distribution: March


Temperature distribution: June


Factors affecting mesosphereGravity wave breaking: -> Meridional circulation from the summer pole to the winter pole• Climate change may change the wave intensity and breaking• Distribution of long-lived constituents• Adiabatic cooling and warming

Tides: Winds, vertical transport, temperature variations

Increase of GHG: CO2, H2O and CH4• Cooling of the mesosphere

Ionization by particles: Solar proton events-> local and non-local changes in chemistry

Ionization by photons: solar EUV, Lyman alpha


Observing mesosphere

Only 1/10000 of ozone is in mesosphere99% of neutral density is below 40 km

GOMOS: UV absorptionMIPAS: IR (non-LTE) emissionSCIAMACHY: UV limb scattering and emissionsOSIRIS: UV limb scattering and emissionsSABER: IR (non-LTE) emissionMLS: microwave emission

EISCAT: incoherent scattering, electron densitySounding rockets


Ozone distribution


Ozone GOMOS-MIPAS comparison

From Verronen et al., Adv. Space Res., 2005

Ozone distribution


Smith et al., JGR113, D17312, 2008


Stratosphere: O3 number density in 2003 (1012cm-3)


CFC+hv

Cl2+HNO3Cl2+hvCl+Cl

Catalytic O3 destruction

Reservoirs

Polar stratospheric clouds

Ozone generation and loss

Cl

Liberation of chlorine

Stratospheric ozone chemistry

Heterogenous chemistry

Extra chlorine from CFCs

O3+hν O+O2

O+O2 O3

Cl+O3NO+O3Br+O3

ClO+O2NO2+O2BrO+O2

ClO+ONO2+O2BrO+O3

Cl+O2NO+O2Br+O2

...

ClO+NO2H+Cl

ClONO2HCl

ClONO2+HCl

T<-85 C


Ozoneproduction

SummerWinter

Long lived: O3

Brewer-Dobson meridional circulation explains thelatitudinal and seasonal distribution of ozone


Mesospheric ozone number density (108cm-3) in 2003


Mesosphere: log10 O3 mixing ratio in 2003


Zoom to ozone minimum


Ozone number density (108cm-3) (30 day median)


Ozone mixing ratio


Total ozone column at 80 km


Catalytic O3 destruction

Ozone generation and loss

Mesospheric ozone chemistry

O3+hν

O+O3

O+O2

2O2

O+O2+M O3

H+O3 OH+O2 OH+O H+O2

!

O3[ ] =k1 O[ ] O2[ ] M[ ]

J

!

O3[ ] =k1 O[ ] O2[ ] M[ ]k2 O[ ] + k3 H[ ]

J

k3

k1

k2

Day Night


!

O3[ ] =k1 O[ ] O2[ ] M[ ]k2 O[ ] + k3 H[ ]

!

k1= 6 "10#34 "300

T

$

% &

'

( )

2.4

!

k2 =1.4 "10#10e#(470

T)

!

k3 = 8 "10#12e#(2060

T)

Mesospheric ozone at night

If T decreases, k1 increases, k2 and k3 decreases:O3 increases

O3 and T anticorrelation!


!

O3[ ] =k1 O[ ] O2[ ] M[ ]k2 O[ ] + k3 H[ ]

!

k1= 6 "10#34 "300

T

$

% &

'

( )

2.4

!

k2 =1.4 "10#10e#(470

T)

!

k3 = 8 "10#12e#(2060

T)

Diffusion +tides

Mesospheric ozone at night

Transport

You really need a chemical transport model to understand the situation.


Ozoneproduction

Stratopause

SummerWinter

H2O

Long lived: O3

GW

H+O3 OH+O2 OH+O H+O2


Meridional circulation


Solar Proton Events

With contributions fromA. Seppälä, FMIP. Verronen, FMI


Movies from http://sohowww.nascom.nasa.gov/ EIT


Movies from http://sohowww.nascom.nasa.gov/ LASCO


Energetic particles and their sources

● Cosmic rays: ions 100MeV-10GeV

● Solar Energetic Particles: p,e10MeV-100MeV

● Radiation belt particles: e,p1MeV-100MeV

● Auroral particles: e,p 100eV-100keV

NASA


Modelling mesosphere


Chemical modelling of the IMPACT -SIC


Energetic Particles and the AtmosphereCharged particles precipitate in the polar areas producing HOx

and NOx gases in mesosphere and stratosphere

HOx (H + OH + HO2)Short lifetimeHOx cycle, upper-stratosphere

+ lower-mesosphereOH + O3 -> HO2 + O2

HO2 + O -> OH + O2

Net: 2Ox -> 2O2

NOx (N + NO + NO2)Loss: photodissociation -> longlived

during night -> transported tostratosphere and lower latitudes

NOx cycle, upper-stratosphere2(NO + O3) -> 2(NO2+ O2)NO2 + hv -> NO + ONO2 + O ->NO + O2

Net: 2O3 -> 3O2


A. Seppälä, FMI


GOMOS NO2 2003-2004 winter (movie)

A. Seppälä, FMI


Northern polar regions NOx from GOMOS

A. Seppälä, FMI


Solar Proton Events – Jan 2005 SPE andthe Tertiary Ozone Maximum

• TOM first reported by Marsh et al. 2001

• Occurs ~72km near the polar nightterminator

• Result of decreased Ox loss by catalyticHOx cycles after decreased HOxproduction with reduced UV radiation.(Less UV ->Less HOx from H2Ophotolysis -> Less catalytic Ox loss)

GOMOS O3 [ppmv]


Third ozone peak in January


GOMOS O3 observations and model results

Seppälä et al., Geophys. Res. Lett. 2006

1D ion and neutral chemistry model SIC

log[HOx(ppbv)]

log[NOx(ppbv)]

[O3] %-change from background[O3] %-change from 10-14 Jan

GOMOS [O3(ppmv)] Lat 65N-75N


Solar proton events and odd H ozone loss


P. Verronen, FMI


Noctilucent clouds


Photograph taken by Mika Yrjölä in August2003. This image portraits a bright noctilucentcloud over Lake Saimaa.Source: english wikipedia (upload 13. Jul 2004by en:User:Explo)


J. Stegman, MISU

NLC movie


GOMOS photometer measurements


OSIRISB. KarlssonD. Degensteinetc.


RESEARCH CHALLENGES FOR THE MESOSPHERE

• Waves, wave breaking

• General mesospheric circulation

• Tides

• Particle events

• Solar EUV variation

• Increased GHG, cooling

• NLC


Summary and references

• Mesosphere is sensitive to external natural forcings and climatechange. There is a need to understand the different components ofchange.

• Measurements are difficult and rare. Need for new measurements.• Modelling of mesosphere is difficult. Modelling needs to include neutral

and ion chemistry and meridional circulation.

Review: A. Smith: Physics and chemistry of the mesopause region,

J. Atmospheric and Solar-Terrestrial Physics, 66. 839, 2004

A. K. Smith and D. R. Marsh: Processes that account for the ozonemaximum at the mesopause, JGR,110, D23305, 2005


Thank you. You have been a wonderful audience!

Challenges for Upper Atmosphere Research

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