Solar particle events and their impact on stratospheric composition

Miriam Sinnhuber

Institut für Umweltphysik, Universität Bremen

Solar particle events and their impact on stratospheric composition

• Origin of particle events

• Atmospheric impacts

• Model predictions

Miriam Sinnhuber

Institut für Umweltphysik, Universität Bremen

Extraterrestrical charged particles:

Protons, electrons, heavier ions from:

- galactic cosmic rays outside solar system

- energetic electrons solar flares,magnetosphere

- solar proton events solar coronal mass ejections, solar flares

Solar proton events and the solar cycle

Sunspot number courtesy of NOAA

GOES daily averaged particle flux

From the homepage of the Ulysses instrument (http://www.sp.ph.ic.ac.uk/~forsyth/reversals)

From the homepage of the Ulysses instrument (http://www.sp.ph.ic.ac.uk/~forsyth/reversals)

From the homepage of the Ulysses instrument (http://www.sp.ph.ic.ac.uk/~forsyth/reversals)

From the homepage of the Ulysses instrument (http://www.sp.ph.ic.ac.uk/~forsyth/reversals)

22 year solar magnetic cycle

Evolution of a CME at the point where magnetic polarities change

Low and Zhang, in: Solar variability and its effect on climate

Solar coronal mass ejections: November 2000

Pictures from several instruments onboard theSOHO satellite

Polar cap: open magnetic field lines

Polar cap: open magnetic field lines

Auroral ovals: impact of particles from the radiation belts

• solar wind

thermosphere• magnetospheric particles

thermosphere • solar energetic particles

mesosphere and stratosphere• galactic cosmic rays

lower stratosphere / surface

Proton fluxes measured by GOES-10 instrument

Modelled ion pair production rate based on GOES, Northern polar cap

Proton fluxes and atmospheric ionisation, October `03

Ionisation rates courtesy of May-Britt Kallenrode, University of Osnabrück

Impact on the atmosphere: Ionisation and radical formation

N2 + p,e N2+,N+

O2 + p,e O2+

lots of ion reactions

H2O

ON,NOH,OH

chemically inert radicals

Impact on the atmosphere: Ion chemistry

Positive ion chemistry scheme from the Sodynkylä ion chemistry model, E. Turunen

Impact on the atmosphere: NOx production

HALOE measurement during July 2000 event

HALOE/UARS at ~68°NNO + NO2 , ppb

Impact on the atmosphere: Ozone destruction

Katalytic ozone destruction:

Odd hydrogen HOx=H+OH+HO2

OH + OH + O3 OH + O2

H + O2

Odd nitrogen NOx=N+NO+NO2

NO + O3

NO2 + O NO + O2

NO2 + O2

> 40 km

< 40 km

Impact on the atmosphere: Ozone destruction

HALOE measurement during July 2000 event

HALOE/UARS at ~68°NOzone change%

Impact on the atmosphere: Ozone destruction

SCIAMACHY measurement during Oct 2003 event

POAM measurement of NO2 at 850 K,

65°S-88°S, Inside vortex

Adapted from Randall et al., GRL, 2001

Long-term impact: Downward transport of NOx

A test of our understanding: Model / measurement comparisons

• 2 D / 1 D global chemistry and transport model of the atmosphere

• NOx / HOx production parameterised

MIPAS / ENVISAT, October 2003, NH ozone

2 D / 1 D model

MIPAS

Data from Lopez-Puertas et al, JGR, 2005

MIPAS

2 D / 1 D model

MIPAS / ENVISAT, October 2003, NH NOx

Outside vortex

POAM measurement of NO2 at 850 K,

65°S-88°S, Inside vortex

POAM data adapted from Randall et al., GRL, 2001

Long-term impact: Downward transport of NOx

MIPAS / ENVISAT, October 2003, NH N2O5

MIPAS 2 D / 1 D model

MIPAS / ENVISAT, October 2003, NH HNO3

MIPAS 2 D / 1 D model

HNO3 formation pathways

Neutral chemistry:

OH + NO2 HNO3

HNO3 formation pathways

Neutral chemistry:

OH + NO2 HNO3

Ion chemistry:

Water cluster ion chain (Kawa et al, 1995)

N2O5 + X+(H2O)n X+(H2O)n-1(HNO3) + HNO3

X+(H2O)n-1(HNO3) + H2O HNO3 + X+(H2O)n

Net: N2O5 + H2O 2 HNO3

A very simple model approach

N2O5 + X+(H2O)n X+(H2O)n-1(HNO3) + HNO3

X+(H2O)n-1(HNO3) + H2O HNO3 + X+(H2O)n

Net: N2O5 + H2O 2 HNO3

Ion densities from equilibrium of ionisation rates and recombination

Protonized ion density = total ion density

Reaction rate of net reaction = rate of N2O5 + X+(H2O)n

HNO3 production by H+(H2O)n cycles

Base run Run with H+(H2O)n cycles

N2O5 production, H+(H2O)n cycles

Base run Run with H+(H2O)n cycles

Conclusions

Solar proton events derive from solar coronal mass ejections or solar flares during solar maximum

During solar proton events, the composition of the middle atmosphere is strongly disturbed, with large ozone losses and NOx production

This disturbance can continue for weeks or month after the events, especially in polar night

NOx production and ozone loss during and after events are well reproduced by models these processes appear to be well understood

Changes of other species – HNO3, N2O5 – are not reproduced at all these are not well understood yet

Model results: July 2000 SPE ozone

HALOE at ~ 68° North

Model at 68° North

Model results: July 2000 SPE NO+NO2

HALOE at ~ 68° North

Model at 68° North

Solar proton events: July 2000

HALOE at ~68°NNO + NO2 changeppb

HALOE at ~68°NOzone change%

The last 400 years of Solar Proton Events:

McCracken et al., JGR, 2000

1989

18591893-1896

„Space age“

SOHO image of a coronal mass ejection

The sun‘s corona during an eclipse (1966)

From: Kivelson and Russell, Introduction to Space Physics