Ionosphere-atmosphere interaction (during solar proton events)
Pekka T. Verronen
Finnish Meteorological Institute, Earth Observation, Helsinki, Finland
Research seminar on Sun-Earth connections, Feb 22, 2006
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 1 / 47 Contents
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 2 / 47 About middle atmosphere and ionosphere Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 3 / 47 About middle atmosphere and ionosphere Middle atmosphere
120 120 110 110 100 100 Mesopause 90 90 80 80 70 70 60 60 Stratopause 50 50 Altitude [km] 40 40 30 30 20 Tropopause 20 10 10 0 0 10 15 20 100 200 300 400 10 10 10 −3 Temperature [K] Concentration [cm ]
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 4 / 47 About middle atmosphere and ionosphere Chemical composition
Main middle atmospheric constituents are N2 (78%) and O2 (21%), the remaining 1% is mostly argon.
Minor constituents, such as O3 and CO2, play important role in atmospheric chemistry, and heating and cooling processes.
Constituents are either produced in the ground level and transported into the middle atmosphere, or produced in-situ by photochemical processes. Some have extra-terrestrial origin.
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 5 / 47 About middle atmosphere and ionosphere Chemical composition II
Continuity equation Time-dependent concentration of an atmospheric species j can be solved from the continuity equation
∂n j = P − L n − ∇ · (n v¯ ) (1) ∂t j j j j j
where nj = concentration, t = time, Pj = local production rate, Lj nj = local loss rate, and v¯j = velocity.
Transport Winds, air parcel transport Diffusion, mixing of gases
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 6 / 47 About middle atmosphere and ionosphere
Dissociation/ionization at alt. zo (see present. by K. Kauristie) Z qj (zo, χ) = I(λ, zo, χ) ηj (λ) σj (λ) nj (zo) dλ, (2) λ
I(λ, zo, χ) = photon flux, σj (λ) = cross section, nj (zo) = gas concentration, ηj = efficiency, λ = wavelength, χ = zenith angle.
Chemical reactions For a two-body reaction
A + B → C + D (3)
the reaction rate R is obtained from
R = k[A][B], (4)
k is the T-dependent reaction rate coefficient (from lab. work), while [A] and [B] are the concentrations of constituents A and B.
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 7 / 47 About middle atmosphere and ionosphere Ozone Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 8 / 47 About middle atmosphere and ionosphere Ozone Ozone is a key constituent in the atmosphere
A minor gas Abundance ≤ 10 ppmv
Absorbs UV radiation Important to the thermal balance and dynamics Protects life on Earth
The ozone layer Located at 15–35 km Affected by CFC gases Ozone hole at Antarctica
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 9 / 47 About middle atmosphere and ionosphere Ozone Ozone chemistry and transport
Catalytic destruction Chapman, [1930]
XO + O → X + O2 O2 + hν → O + O X + O3 → XO + O2 O + O2 + M → O3 + M Net : O3 + hν → O2 + O O + O3 → 2O2 O + O3 → 2O2 X can be Br, Cl, OH, or NO
Distribution by transport Production depends upon solar light, strongest in the equator Highest amount are found in the polar regions Chemical loss processes require solar radiation
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 10 / 47 About middle atmosphere and ionosphere Ozone Total ozone column EOS-Aura/OMI instrument
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 11 / 47 About middle atmosphere and ionosphere Ozone Ozone yearly mean for 2003 Envisat/GOMOS instrument
O3 mixing ratio 100 8 5 10 6 9 7 7 7 6
2
1
0.2 8 8
0 8 7 7 8 9 6 6 90 4 5 7 9
0.1
4 5
3 3 4 2 2 3 65 1 1
0.5 0.4
0.4 0.3 0.3 0.5 0.3 0.5 80 0.2 0.4 8 0.5 0.2 0.2 0.4 0.3 0.5 0.40.3 1 1 70 1 7 0.055176
60 6
0 0.2 2 2 2 50 3 5 0.1 3 Altitude [km] 4 4 3
0.5 5 5
10.4 0.3 6 4 40 7 7 4
6
6 7 8 9 8 30 0.055176 5 8 3 9 5 7 65 4 2 4 3 4 3 2
0.2
0 3 20 0.5 1 2 2 0.2 0.30.4 1 1 0.40.5 0.1 0.40.5 10 0.3 0.3 1 −80 −60 −40 −20 0 20 40 60 80 Latitude
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 12 / 47 About middle atmosphere and ionosphere Catalysts NOx and HOx Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 13 / 47 About middle atmosphere and ionosphere Catalysts NOx and HOx Odd nitrogen and odd hydrogen
Odd hydrogen HOx = (H + OH + HO2)
Odd nitrogen NOx = (N + NO + NO2)
Are chemically active, main catalysts of ozone loss in the upper stratosphere (NOx) and mesosphere (HOx).
Particle precipitation in the polar regions contributes to their production −→ Important role in Sun-Earth connection.
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 14 / 47 About middle atmosphere and ionosphere Catalysts NOx and HOx
NOx production OHx production In the stratosphere, and From water vapour lower thermosphere 1 1 H2O + O( D) → 2OH N2O + O( D) → 2NO
+ ∗ H2O + hν → OH + H N2 + hν → N2 + e ∗ ∗ e + N2 → 2N + e OHx loss N + O2 → NO + O “Cannibalistic” reactions, such as NOx loss Requires solar radiation OH + HO2 → H2O + O2
NO + hν → N + O Short chemical lifetime, transport can be neglected N + NO → N2 + O
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 15 / 47 About middle atmosphere and ionosphere Catalysts NOx and HOx Odd nitrogen profiles
NO at noon, equinox, high latitude, SIC model x 100 Production from N N 2 NO NO 90 2
80
70
Altitude[km] 60
50
40 Production from N O 2
30 5 6 7 8 9 10 10 10 10 10 Concentration [cm−3]
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 16 / 47 About middle atmosphere and ionosphere Catalysts NOx and HOx Odd hydrogen profiles
HO at noon, equinox, high latitude, SIC model x 100
Dynamical control
90 Decrease of H O 2
80
70
Altitude[km] 60
50
40 H OH HO 2 30 5 6 7 8 9 10 10 10 10 10 Concentration [cm−3]
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 17 / 47 About middle atmosphere and ionosphere D region of ionosphere Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 18 / 47 About middle atmosphere and ionosphere D region of ionosphere Ionospheric D-region
Lowest region of the ionosphere, at 60–90 km, overlaps with the mesosphere, relatively low electron density: 102 − 104 cm−3 Chemically much more complex than the regions above, because minor neutrals become important
Ionization sources Specialities Lyman-α multitude of ions EUV negative ions hard X-rays cluster ions particle precipitation complex chemistry
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 19 / 47 About middle atmosphere and ionosphere D region of ionosphere Quiet-time ionization rates
120
110
100
90 Altitude [km] 80
N2 (EUV/X−ray) O2 (EUV/X−ray) 70 NO (Lyman−alpha) O2(1Dg) (EUV) N2 (GCR) N2 (photoelectrons) 60 4 5 6 7 8 9 10 10 10 10 10 10 10 10 Ionisation rate [m−3 s−1]
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 20 / 47 About middle atmosphere and ionosphere D region of ionosphere Charge balance
recombination recombination
ionisation neutral side
ionic side
X+ e-
attachment X- detachment
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 21 / 47 About middle atmosphere and ionosphere D region of ionosphere Positive ion reactions
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 22 / 47 About middle atmosphere and ionosphere D region of ionosphere Negative ion reactions
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 23 / 47 About middle atmosphere and ionosphere D region of ionosphere Profiles of electrons and ions
Noon Midnight 90 90 Positive ions Negative ions Electrons 85 85
80 80
75 75 Altitude [km] 70 70
65 65
60 60 7 8 9 10 7 8 9 10 10 10 10 10 10 10 10 10 Concentration [m−3] Concentration [m−3]
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 24 / 47 About middle atmosphere and ionosphere D region of ionosphere Ion composition
Positive ions Negative ions + − Primary ion: NO , Primary ion: O2 , − produced by Lyman-α e + O2 + M → O2 + M − Most abundant: Terminal ions: CO3 , + − − H (H2O)n NO3 , HCO3
Ion composition is affected by variation in ionization, and (changing) concentrations of minor neutral constituents
Few rocket measurements of ion composition have been made, there are several issues still to be solved
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 25 / 47 Solar proton events, forcing from the Sun Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 26 / 47 Solar proton events, forcing from the Sun Coronal Mass Ejections As seen by SOHO/LASCO
Originating from Sun High-energy protons are emitted, sometimes toward Earth Charged particles precipitate into atmosphere in polar regions ⇒ Solar Proton Event SPEs are sporadic Few per solar maximum
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 27 / 47 Solar proton events, forcing from the Sun Proton flux at Geostationary orbit GOES-11 measurements
10 4
] Energies > 30 MeV −1 sr −1
s 10 2 −2
10 0 Proton flux [Counts cm
10 −2 26 28 30 01 03 05 07 09 11 13 15 Day in October−November 2003
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 28 / 47 Solar proton events, forcing from the Sun Geomagnetic rigidity cutoff
Charged particles are Are guided by Earth’s magnetic field and penetrate the atmosphere in the polar regions Cutoff. Each location has a minimum rigidity, i.e. momentum per charge, which is required of a particle to reach it. Cutoff varies with time
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 29 / 47 Solar proton events, forcing from the Sun Increase in D-region ionization Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 30 / 47 Solar proton events, forcing from the Sun Increase in D-region ionization Ionization in the polar atmosphere Model calculations using GOES data, proton energies ≥ 1 MeV
120 Solar EUV radiation 110 Galactic Cosmic Rays Proton precipitation 100 90 80 70 60 Altitude [km] 50 40 30 20 10 −2 10 0 10 2 10 4 Ionization rate [cm −3 s −1 ]
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 31 / 47 Solar proton events, forcing from the Sun Increase in D-region ionization Total ionization rate due to proton precipitation
1 ZZZ dE Q = F(E) sin θ dθdφdE (5) ∆ dx
Symbol explanation ∆ = average ionization energy ≈ 35 eV F(E) = flux of protons above the atmosphere −1 dE dR(E,zo,θ) dx = dE = energy loss per unit density travelled R(E, z , θ) = R(E) − 1 R ∞ n(z) dz = remaining range at z o n(0) zo cos θ o R(E) = range of a proton with energy E (from lab. measurements)
Total ionization rate is divided between N2,O2, and O + + + + Primary products are N2 ,N ,O2 ,O , as well as N and O
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 32 / 47 Solar proton events, forcing from the Sun Production of NOx and HOx , and subsequent loss of ozone Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 33 / 47 Solar proton events, forcing from the Sun Production of NOx and HOx , and subsequent loss of ozone From particle precipitation to ozone loss
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 34 / 47 Solar proton events, forcing from the Sun Production of NOx and HOx , and subsequent loss of ozone Production of OH and NO
Energetic particles precipitate into atmosphere
N + O + 2 2 O+ N N(2D) O + 4 O +(H O) 2 2 HO +(H O) NO 3 2 n OH H
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 35 / 47 Solar proton events, forcing from the Sun Production of NOx and HOx , and subsequent loss of ozone
Reactions producing NOx and HOx
NOx production OHx production By particle impact ionization, By ion chemistry, e.g.
dissociation, ion chemistry + O2 (H2O) + H2O → ∗ + ∗ ∗ + N2 + p → N2 + e + p H (H2O) + OH + O2 ∗ ∗ + e + N2 → 2N + e H (H2O) + nH2O → + N + O2 → NO + O H3O (H2O)n + − H3O (H2O)n + e → + + N2 + O → NO + N (n + 1)H2O + H + NO + e → NO Net : H2O → OH + H
Ozone destruction follows by the catalytic reaction cycles!
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 36 / 47 Solar proton events, forcing from the Sun Production of NOx and HOx , and subsequent loss of ozone
Response of HOx and NOx to the proton forcing Modelling results, high latitude winter location
8 HOx = H + OH + HO2 x 10 NOx = N + NO + NO2 7
6 ] ] 7 −3 10 −3 5
4
3
2 Concentration [cm Concentration [cm 6 10 1
0 26 27 28 29 30 31 01 02 26 27 28 29 30 31 01 02 Day of Oct−Nov, 2003 Day of Oct−Nov, 2003
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 37 / 47 Solar proton events, forcing from the Sun Production of NOx and HOx , and subsequent loss of ozone
NOx after hard auroral electron precipitation
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 38 / 47 Solar proton events, forcing from the Sun Production of NOx and HOx , and subsequent loss of ozone Duration of ozone depletion Depends on the level of solar illumination
Mesosphere/Summer pole
Both HOx and NOx are short-lived Fast recovery due to photodissociation Ozone depletion lasts for days
Stratosphere/Winter pole
NOx is long-lived and can be transported Slow recovery depletion can last for months
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 39 / 47 Solar proton events, forcing from the Sun Production of NOx and HOx , and subsequent loss of ozone Relative change of ozone during an SPE SIC model vs. GOMOS at 70 km
20
0
−20
−40
−60
Rel. change of ozone [%] Altitude = 70 km
−80
−100 23 24 25 26 27 28 29 30 31 01 02 03 04 05 06 Day of October−November 2003
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 40 / 47 Open questions Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 41 / 47 Open questions Questions about particle precipitation
1) Night-side effects Models predict long-lasting ozone depletion No satellite measurements existed...... but now GOMOS has solved the question!
2) Production of HOx Based on model predictions Satellite measurements required
3) Long-term effect on stratosphere and ozone layer? Models suggest: particle precipitation is important Confirmation requires measurements in polar night conditions
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 42 / 47 Open questions
10-day average ozone and NO2 concentrations Latitudes ≥ 45◦ shown at altitude 46 km, SPE is on from day 300 to 310
281 − 300 301−310 311−320 321−330 331−340 341−350 351−360
O 10 3 7 8 9 10 11 12 13 14 10 NO 108 2 1 2 3 4 5 6 7 8
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 43 / 47 Open questions
Measured HOx during the January 2005 SPE MLS/EOS-Aura vs. SIC model
January 15, 2005 January 18, 2005 100 100
Before SPE During SPE 90 90
80 80
70 70
60 60 Altitude [km] Altitude [km] 50 50
40 40
30 30
20 20 5 6 7 5 6 7 10 10 10 10 10 10 Concentration [cm−3] Concentration [cm−3]
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 44 / 47 Open questions Further reading Outline
1 About middle atmosphere and ionosphere Ozone Catalysts NOx and HOx D region of ionosphere
2 Solar proton events, forcing from the Sun Increase in D-region ionization Production of NOx and HOx , and subsequent loss of ozone
3 Open questions Further reading
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 45 / 47 Open questions Further reading
Recent papers by FMI/Earth Observation
P. T. Verronen, A. Seppälä, M. A. Clilverd, C. J. Rodger, E. Kyrölä, C.-F. Enell, E. Turunen, and Th. Ulich, Diurnal variation of ozone depletion during the October-November 2003 solar proton events, J. Geophys. Res., 110, A09 S32, 2005.
A. Seppälä, P. T. Verronen, E. Kyrölä, S. Hassinen, L. Backman, A. Hauchecorne, J.-L. Bertaux, and D. Fussen, Solar proton events of October-November 2003: Ozone depletion in the Northern Hemisphere polar winter as seen by GOMOS/Envisat, Geophys. Res. Lett., 31, L19 107, 2004.
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 46 / 47 Open questions Further reading
Some good books
Brasseur, G. P. and Solomon, S., Aeronomy of the Middle Atmosphere, Springer, Dordrecht, 3rd revised and enlarged edn., 2005.
Hargreaves, J. K., The solar-terrestrial environment, Cambridge Atmospheric and Space Science Series, Cambridge University Press, Cambridge, UK, 1992.
Rees, M. H., Physics and chemistry of the upper atmosphere, Cambridge atmospheric and space science series, Cambridge University Press, Cambridge, UK, 1989.
P. T. Verronen (FMI, Earth Observation) Ionosphere-atmosphere interaction Sun-Earth connections 47 / 47