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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
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 2
Atmospheric layers
Lutgens and Tarbuck's The Atmosphere, 2001
Structure and features
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 3
protonselectrons photons
Gravitywaves
Tides
Chemistry
Non-LTE Atoms, Ions
Mesospheric phenomena
Vertical transport and diffusion
Mesosphericcirculation
Emissionsmeteor dustShuttleexhaust
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 4
Temperature distribution: JanuarySources: ECMWF (z<45 km), MSIS90 (z>45 km)
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 7
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
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 8
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
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 10
Ozone GOMOS-MIPAS comparison
From Verronen et al., Adv. Space Res., 2005
Ozone distribution
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 12
Stratosphere: O3 number density in 2003 (1012cm-3)
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 13
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
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 14
Ozoneproduction
SummerWinter
Long lived: O3
Brewer-Dobson meridional circulation explains thelatitudinal and seasonal distribution of ozone
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 15
Mesospheric ozone number density (108cm-3) in 2003
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 18
Ozone number density (108cm-3) (30 day median)
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 21
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
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 22
!
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!
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 23
!
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.
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 24
Ozoneproduction
Stratopause
SummerWinter
H2O
Long lived: O3
GW
H+O3 OH+O2 OH+O H+O2
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 27
Solar Proton Events
With contributions fromA. Seppälä, FMIP. Verronen, FMI
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 28
Movies from http://sohowww.nascom.nasa.gov/ EIT
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 29
Movies from http://sohowww.nascom.nasa.gov/ LASCO
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 30
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
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 36
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
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 38
GOMOS NO2 2003-2004 winter (movie)
A. Seppälä, FMI
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 39
Northern polar regions NOx from GOMOS
A. Seppälä, FMI
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 40
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]
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 42
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
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 46
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)
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 50
RESEARCH CHALLENGES FOR THE MESOSPHERE
• Waves, wave breaking
• General mesospheric circulation
• Tides
• Particle events
• Solar EUV variation
• Increased GHG, cooling
• NLC
ESA AATC Oxford 2008 Upper Atmosphere - Erkki Kyrölä 51
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