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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. Introduction. Some Atmospheric coupling processes:.

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The effect of high energy electron precipitation in MLT (Mesosphere-Lower Thermosphere)

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  1. 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

  2. Introduction Some Atmospheric coupling processes: E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

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

  12. A network is better! E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

  13. 2-D reconstruction of an auroral arc E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

  14. 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

  15. 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

  16. 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

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

  18. Tomography across aurora ! E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

  19. 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

  20. 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

  21. 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

  22. 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

  23. 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

  24. 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

  25. 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

  26. 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

  27. SPE Jan 2005 Seppälä et al., (2006) E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

  28. 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

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

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

  31. 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

  32. 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

  33. 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

  34. 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

  35. 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

  36. 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

  37. 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

  38. 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

  39. Ion reactions producing odd nitrogen E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

  40. 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

  41. 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

  42. 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

  43. SGO all-sky camera, Feb 2006 E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

  44. 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

  45. 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

  46. 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

  47. NO produced by aurora Verronen et al., (2005) E. Turunen / IPY Heliosphere impact on geospace, Kick-off meeting, Feb 5-9, 2007, Helsinki

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

  49. 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

  50. 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

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