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The effect of high energy electron precipitation in MLT (Mesosphere-Lower Thermosphere). E. Turunen Sodankylä Geophysical Observatory,Sodankylä, Finland. See also related talks by Annika Seppälä and Pekka Verronen in this meeting. Introduction. Some Atmospheric coupling processes:.

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the effect of high energy electron precipitation in mlt mesosphere lower thermosphere
The effect of high energy electron precipitation in MLT (Mesosphere-Lower Thermosphere)

E. Turunen

Sodankylä Geophysical Observatory,Sodankylä, Finland

See also related talks by Annika Seppälä and Pekka Verronen in this meeting

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

introduction
Introduction

Some Atmospheric

coupling processes:

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide3

Chapman SEP conference 2004:

”We think we do understand the atmosphere...?”

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

do we understand
Do we understand?

The connection between space weather and Earth’s climate?

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

do we understand1
Do we understand?

The effect of variable cosmic ray input on Earth’s atmosphere?

The effect of hard X-rays during solar flares on Earth’s middle and upper atmosphere?

The global effect of relativistic electron precipitation and its variability?

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

do we understand2
Do we understand?

The effect of solar cycle variation in soft X-ray and EUV radiation forcing on Earth’s middle and upper atmosphere?

The mid-term and short-term effects of such variation, due to day-to-day variability of solar activity?

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide7

Do we understand the impact of solar and magnetospheric energetic particles on the chemistry of the middle and upper atmosphere of Earth?

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

particle precipitation causes
Particle precipitation causes:
  • Increased energy deposition
    • Dynamic effects
  • Increased ionisation
    • Conductivity variations
    • Radio wave propagation effects
    • Chemistry effects
  • Increased dissociation
    • Chemistry effects
  • Increased excitation

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide9
Thermospheric NO might be carried down to the stratosphere, where it would enhance the background density of odd nitrogen and participate in the catalytic destruction of ozone [Siskind et al., 1997,Siskind, 2001 ].
  • Mesospheric and stratospheric NO might be created in situ by very high energy particles
  • As an example, Reid et al. [1991] give an example of 20% ozone decrease at the altitude of 45 km in response to solar proton events in late 1989

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

how do we monitor these effects
How do we monitor these effects?
  • Ground-based networks
    • Magnetometers
    • All-sky cameras

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

photometers and spectrometers
Photometers andspectrometers

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

a network is better
A network is better!

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

2 d reconstruction of an auroral arc
2-D reconstruction of an auroral arc

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

radars and radio receivers
Radars and radio receivers
  • Ionospheric sounders
    • Real time digital sounder network
  • Coherent radars
    • STARE, CUTLASS
  • Incoherent scatter radars
    • EISCAT UHF and VHF, ESR
  • Satellite tomography
    • LEO satellites, GPS
  • MF and HF radio propagation
  • VLF radio propagation
  • Riometers
    • Imaging riometers, GLORIA-proposal

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide15

EISCAT Incoherent Scatter Radars in Tromsø and Svalbard

UHF radar

VHF radar

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

finnish riometer network
Finnish riometer network
  • Riometers in Northern Scandinavia
  • - continuous monitoring of total electron concentration during excessive ionisation
  • IRIS, imaging riometer at Kilpisjärvi

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

satellite tomography
Satellite tomography

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide18

Tomography across aurora !

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

satellite measurements
Satellite measurements
  • ENVISAT
    • GOMOS
      • O3
      • stratosphere-mesosphere
    • MIPAS,
      • O3, Noy
      • stratosphere
    • SCIAMACHY
      • O3,Nox
      • stratosphere-mesosphere
  • Odin
    • OSIRIS
      • O3
    • SMR,
      • O3,NO,HO2
  • EOS Aura
    • OMI
    • MLS

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

experimental data to compare
Experimental data to compare
  • UARS
    • HALOE
      • O3,NOy
  • SNOE
    • UVS
      • NO
  • TIMED
    • SABER
      • O3,NO,OH

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

solar radiation control of chemistry
Solar radiation control of chemistry
  • Upper panel:
    • solar zenith angle between 1300 and 1700 UT, Oct 23, 1989
  • Middle panel
    • relative flux of UV light (<318 nm) at 40-100 km
  • Lower panel
    • relative flux of visible light (<422 nm) at 40-100 km

(from P.Verronen et al., 2006)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide22

Particle precipitation and ozone

When protons or electrons precipitate into atmosphere ions and secondary electrons are produced, also some NOx via dissociative ionization of N2. Ions and electrons react chemically and produce odd hydrogen, odd nitrogen and negative ions. This trio then affects ozone (loss) via catalytic reaction chains.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide23

p

p

p

p

p

O

O2

N2

N2+

O2+

O+

e

O2

N2

NO+

O2

O

O4+

N

N(2D)

H2O

O2+ (H2O)

HO3+ (H2O)n

NO

H2O

e

OH

H

NO + O3->NO2 +O2

NO2 + O3->NO +2O2

OH + O->H + O2

H + O3->OH +O2

Particle precipitation

loss of ozone

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

motivation
Motivation
  • Particle precipitation in the upper atmosphere affects odd nitrogen (N+NO+NO2) and odd hydrogen (H+HO+HO2)
  • In polar night conditions, NO is long-lived and may be carried vertically down to lower altitudes and horisontally to lower latitudes
  • Mesospheric and stratospheric NO might be created in situ by very high energy particles

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

motivation1
Motivation
  • Odd hydrogen and odd nitrogen destroy ozone
  • Ozone is important in the radiation balance of the upper atmosphere
  • Is this a mechanism to couple space weather variations to variations in Earth’s climate?

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide26

Finnish work on Solar Proton Events (SPE)

Several solar proton events were studied, in order to see the effects of increasing ionisation on ozone.

Production/ Loss model is confirmed experimentally

(recent works by Verronen et al, Seppälä et al., Clilverd et al., Rodger et al.)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

spe jan 2005
SPE Jan 2005

Seppälä et al., (2006)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

example application
Example application
  • Ozone destruction during SPE Oct-Nov 2003
    • quantitative model estimate confirmed by ENVISAT/ GOMOS measurements
      • Verronen et al, (2005)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide29

SIC model

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide30

SIC model

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sic model
SIC model
  • The Sodankylä Ion Chemistry Model (SIC) was applied first by Burns et al. [1991] in a study of EISCAT radar data, and thereafter by, e.g., Turunen [1993], Rietveld et al. [1996], Ulich et al. [2000], Verronen et al. [2002] and Clilverd et al. [2005]
  • A detailed description of the original SIC model, in which only ion chemistry was considered, can be found in the work of Turunen et al. [1996].
  • The latest version solves the concentrations of 63 ions, including 27 negative ions as well as 13 neutral species (O(3P), O(1D), O3, N(4S), N(2D), NO,NO2, NO3, HNO3, N2O5, H, OH, and HO2)
  • In this study also O2(1Dg) and H2O2as unknowns.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sic model cont
SIC model cont.
  • Altitude range is from 20 to 150 km, with 1-km resolution.
  • Several hundred chemical reactions are taken into account.
  • External forcing due to solar radiation, electron and proton precipitation, and galactic cosmic rays.
  • The background neutral atmosphere is generated using the MSISE-90 model [Hedin, 1991] and tables given by Shimazaki [1984].
  • The former provides altitude profiles of N2, O2, Ar, He, and temperature with 1-km resolution for any given set of time, geographic location, magnetic Ap index, and solar F10.7 flux.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sic model cont1
SIC model cont.
  • The latter provides concentrations of O2(1Dg), N2O, H2, H2O, H2O2, HNO2, HCl, Cl, ClO, CH3, CH4, CH2O, CO, and CO2 for noon and midnight conditions at altitudes 10, 15, 20, 25, 30, 45, 60, 80, and 100 km, which are then converted into altitude profiles of 1-km resolution by interpolation.
  • For the 1-km Shimazaki-based profiles, interpolation with respect to solar flux is used to make the transition from day to night and vice versa.
  • The concentrations of H2O and CO2 are calculated using fixed volume mixing ratio profiles, the default values are 5 ppmv (below 80 km) and 335 ppmv, respectively.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sic model cont2
SIC model cont.
  • The solar flux is estimated by the SOLAR2000 model [Tobiska et al., 2000], version 2.23.
  • The scattered component of the solar Lyman-a flux is included using the empirical approximation given by Thomas and Bowman [1986].
  • Solar radiation in wavelengths between 1 and 422.5 nm is considered, ionizing N2, O2, O, Ar, He, NO, O2(1Dg), CO2, and dissociating N2, O2, O3, H2O, H2O2, NO, NO2, HNO3 , and N2O5.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sic model cont3
SIC model cont.
  • The photoionization/dissociation cross sections as well as branching ratios for different products were gathered from various sources [Ohshio et al., 1966; McEwan and Phillips, 1975; Torr et al., 1979; Shimazaki, 1984;World Meteorological Organization, 1985; Rees, 1989; Fuller-Rowell, 1993; Minschwaner and Siskind, 1993; Siskind et al., 1995; Koppers and Murtagh, 1996; Sander et al., 2003].
  • The numerous sources of reaction rate coefficients for the ionic reactions are listed in the work of Turunen et al. [1996] along with the additions listed in the work of Verronen et al. [2002].

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sic model cont4
SIC model cont.
  • The negative ion chemistry scheme and the ion-ion recombination coefficient have been recently checked and revised according to and references in Kazil et al. [2003].
  • The neutral chemistry includes 59 reactions of the modeled neutral species, for which the rate coefficients have been updated according to Sander et al. [2003].
  • Most of these reactions are listed in the work of Verronen et al. [2002].
  • Recent additions and changes are presented in Table 1 of Verronen et al. [2005]

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sic model cont5
SIC model cont.
  • The model includes a vertical transport code, described by Chabrillat et al. [2002], which takes into account molecular and eddy diffusion.
  • Within the transport code the molecular diffusion coefficients are calculated according to Banks and Kockarts [1973].
  • We use a fixed eddy diffusion coefficient profile, which has a maximum of 1.3 x 106 cm2 s -1 at 102 km.
  • The SIC model can be run either in a steady-state or a time-dependent mode.
  • Mostly we used the time-dependent mode which exploits the semi-implicit Euler method for stiff sets of equations [Press et al., 1992], in order to advance the concentrations of the chemical species in time.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sic model cont6
SIC model cont.
  • Vertical transport and chemistry are advanced in 15-min intervals during which the background atmosphere and external forcing are kept constant.
  • In the beginning of every interval all modeled neutrals, except the short-lived constituents O(1D) and N(2D), are transported.
  • Next, new values for solar zenith angle, background atmosphere, and ionization/dissociation rates due to solar radiation and particle precipitation are calculated.
  • Finally, the chemistry is advanced.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide39

Ion reactions producing odd nitrogen

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

problems
Problems
  • Inputs for model work are not well known
    • We need to know the energy and flux of the precipitating particles (solar origin/magnetospheric response)
    • Details of many chemical processes are not known
    • Parametrizations and extrapolations are used in models
  • We need more measurements
    • Some key properties not measured at all from satellites
    • Measurements are often integrated averages
    • Simultaneous satellite and ground based measurements needed

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

energy distribution of precipitating electrons
Energy distribution of precipitating electrons
  • Optical data combined with other data
    • M. Ashrafi et al., Ann. Geoph., 2005
      • imaging riometer + all-sky optical data
      • DASI 557.7 nm + imaging riometer (+EISCAT calibration) -> energy maps, assuming Maxwellian spectra
      • comparison with DMSP satellite data, conjugate passes
    • H. Mori et al., Ann. Geoph., 2004
      • imaging riometer + meridian scanning photometer
      • ratio of 630.0 nm and 427.8 nm -> total flux + characteristic energy
      • Calculated CNA / observed CNA -> spectral shape
    • M. Kosch et al., JGR, 2001
      • original work on energy maps using DASI and IRIS

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide42

Fig. 7 by Lummerzheim et al., 1990

  • Empirical relationship I630.0 / I427.8 versus characteristic energy of the precipitating electrons

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sgo all sky camera feb 2006
SGO all-sky camera, Feb 2006

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

energy distribution of precipitating electrons1
Energy distribution of precipitating electrons
  • We propose to combine standard optical data with:
    • new digital ionosonde data with high dynamical range
      • E-region characteristics obtained even during auroral events
      • information on high-energy particles in the minimum frequency
    • detailed ion-chemistry modeling
      • any assumed energy spectrum of precipitating particles can be used as input
      • resulting electron density profile can be compared with ionosonde data
      • high energy part can be compared with riometer data

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sgo alpha wolf
SGO Alpha Wolf
  • SGO built a new CW FM chirp ionosonde in 2005
    • 24 bit recording
    • 8 crossed loop antennae in receiver (20 units ready)
    • f=0.5-16 MHz
    • in operation since November, 2005

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

sgo alpha wolf1
SGO Alpha Wolf
  • Extended sounding capability
    • large dynamical range -> nearly continuous information of E-region characteristics even during auroral events
    • soundings start at 0.5 MHz
    • fmin can be used to map high energy precipitation

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

no produced by aurora
NO produced by aurora

Verronen et al., (2005)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

electron precipitation
Electron precipitation

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

electron precipitation1
Electron precipitation
  • Electron density as function of altitude at noon, without auroral activity during the previous night (blue) and with auroral activity during the previous night (red).

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

afternoon absorption spike events
Afternoon absorption spike events
  • Also isolated spikes found
  • Often extremely large absorption values >5 dB,up to 15 dB
  • Well-defined, confined region of absorption in IRIS field of view
  • Example: IRIS beam 32 on 2002-10-27 at 1811 UT

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

example iris data 1995 11 01
Example:IRIS data1995/11/01

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

iris data 2005 01 02
IRIS data 2005/01/02

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

relativistic electrons
Relativistic electrons?
  • Easy to produce high absorption by relativistic electron precipitation
  • What is the flux?
  • Example: SAMPEX data on four consecutive days in 1992, flux of electrons >400keV (precipitating fluxes)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

what is the energy of the electrons
What is the energy of the electrons?
  • Foat et al. [GRL, 1998] report balloon observations of X-rays, consistent with precipitation of monoenergetic 1.7 MeV electrons, near Kiruna on Aug 20, 1996 at 1532 UT (L=5.8)
  • Lorentzen et al. [JGR, 2000] give interpretation of this as a selective precipitation of ambient relativistic electrons from radiation belt

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

x ray spectra
X ray spectra

Observed in Kiruna,

Aug 20, 1996

at 1532 UT

Upper solid line:

Model calculation

for 1.7 Mev electrons

Fitted to corrected

spectrum

Lorentzen et al. [JGR, 2000]

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

absorption seen by riometer
Absorption seen by riometer

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

eiscat observation of rep
EISCAT observation of REP

EISCAT VHF, GEN11, 1995/09/15

Electron density from fitted ISR D-region spectra show enhanced ionisation at 1310:

Power profile

Electron density

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

iris data 1995 09 15
IRIS data 1995/09/15

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

atmospheric effects of rep events
Atmospheric effects of REP events

Ionisation

rates:

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

gaines et al spectrum 3 hrs
Gaines et al. spectrum, 3 hrs

Assume

constant

ionisation

with time,

duration

3 hours:

Response

in Ne

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

gaines et al spectrum 3 hrs1
Gaines et al. spectrum, 3 hrs

Note:

time axis starts

at 12:00 and

after 24:00

jumps to 00:00

Response

in NO

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

gaines et al spectrum 3 hrs2
Gaines et al. spectrum, 3 hrs

Response

in O3

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

gaines et al spectrum 24 hrs
Gaines et al. spectrum, 24 hrs

Assume

constant

ionisation

with time,

duration

24 hours:

Response

in O3

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

energy of the electrons from vlf data
Energy of the electrons from VLF data?

Model calculation:

Set up a constant

ionisation at all

altitudes, duration

0.5 seconds.

Calculate the time

development of

electron density

after the ionisation

burst.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

energy of the electrons from relaxation
Energy of the electrons from relaxation?

Constant ionisation at

all altitudes on for 0.5

seconds:

Relaxation time of

the elevated electron

density is strongly

dependent on

altitude.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

use decay time of a spike in data
Use decay time of a spike in data

Relaxation is a result

of several processes

which have different

characteristic times.

Fitting a slow and fast

exponential decay to

SIC model results:

=>

At lower altitudes fast

processes dominate.

At higher altitudes,

there are only slow

processes.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

electron penetration

Electron penetration

If REP microbursts would be nearly monoenergetic electrons, we could estimate the energy by fitting a model decay time to the observed decay in VLF data during a microburst.

altitude [km]

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

vlf monitoring of precipitation
VLF monitoring of precipitation

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

actual vlf data
Actual VLF data

Sodankylä AARDDVARK receiver, 21 Jan 2005 (from C. Rodger et al., 2006)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

monoenergetic electrons

Monoenergetic electrons

An example of decay due to a 0.1 s lasting ionisation by monoenergetic electrons of 1,2, and 3 MeV, shown together with experimental data from the Sodankylä AARDDVARK receiver (from C. Rodger et al., 2006)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

model of chorus driven wep

Model of chorus-driven WEP

(model by Jacob Bortnik)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

monoenergetic electrons1

Monoenergetic electrons

Time varying electron number density calculated by the SIC model, showing the decay of a chorus-produced ionospheric change due to the model fluxes (left), and time varying VLF perturbation produced by the chorus-driven precipitation spectra (right), to be contrasted with the observed FAST VLF perturbation(from C. Rodger et al., 2006)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

examples of rep bursts
Examples of REP bursts

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

modelling a rep burst
Modelling a REP burst

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

rep effect on neutrals
REP effect on neutrals
  • Assuming ≈1 MeV-energy particles:
    • Individual short duration burst have negligible effects on neutrals
    • Repeated precipitation or duration in the order of 10 minutes may produce a few percent decrease in local ozone concentration
    • Long-lasting events (days or more) can have significant effects even with low fluxes!!!

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

slide76

REP effects

  • There is a need to deduce precipitating electron characteristics
    • Relativistic microbursts could be used together with chemistry modeling
  • Multi-instrument approach is necessary - in addition to possible estimates from relaxation time:
    • multiwavelenght all-sky imaging, high dynamic range ionosonde, with ion-chemical modeling, can be used
    • photometer data would be favoured
    • imaging riometer data should be added
  • Ultimately X-ray satellite imaging needed

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

cmat2 3 d gcm
CMAT2: 3 D GCM

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

cmat2 3 d gcm1
CMAT2: 3 D GCM
  • Citation: Dobbin, A. L. , A. D. Aylward, and M. J. Harris (2006 ), Three-dimensional GCM modeling of nitric oxide in the lower thermosphere ,J. Geophys. Res. ,111 ,A07314 , doi: 10.1029/2005JA011543
  • CMAT simulations suggest that under moderate geomagnetic conditions, the most equatorward geographic latitudes to be influenced by aurorally produced NO are 30°S and 45°N. Under conditions of high geomagnetic activity, aurorally produced NO is present at latitudes poleward of 15°S and 28°N.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

spe oct 2003 gomos
SPE Oct 2003, GOMOS

From:

A.Seppälä et al.

(2006)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

gomos no 2
GOMOS, NO2

From:

A.Seppälä et al.

(2006)

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

how can ipy help

How can IPY help?

Solar proton precipitation at polar cap areas,

auroral electron precipitation at the auroral zone,

relativistic electron precipitation at auroral and sub-auroral latitudes,

variable cosmic ray ionisation,

solar extreme ultraviolet and X-radiation,

all are ionising energy inputs to the mesosphere and lower thermosphere (MLT). They all show large variations on different timescales, causing changes in the ion and neutral composition in the MLT region. During extreme ionisation events, direct effects in the stratosphere can be seen.

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

thank you
Thank you!

...work in progress....

E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki