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University of Illinois, Urbana-Champaign, USA PMOD/WRC, Switzerland

ELECTRON PRECIPITATION EFFECTS ON CHEMICAL COMPOSITION AND CLIMATE. E. Rozanov, L. Callis, M. Schlesinger, F. Yang, N. Andronova and V. Zubov. University of Illinois, Urbana-Champaign, USA PMOD/WRC, Switzerland NASA/Goddard Space Flight Center , USA

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University of Illinois, Urbana-Champaign, USA PMOD/WRC, Switzerland

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  1. ELECTRON PRECIPITATION EFFECTS ON CHEMICAL COMPOSITION AND CLIMATE E. Rozanov, L. Callis, M. Schlesinger, F. Yang, N. Andronova and V. Zubov University of Illinois, Urbana-Champaign, USA PMOD/WRC, Switzerland NASA/Goddard Space Flight Center, USA University of Michigan, Ann Arbor, USA Main Geophysical Observatory, Russia

  2. Outline • Motivation • Experimental set-up • Results

  3. Motivation The simulated responses of ozone and temperature to solar irradiance variation over the 11-year solar cycle do not agree with the solar signal extracted from the observational data

  4. Ozone (%), Solar max - Solar min Hood (2002) Rozanov et al 2005

  5. ( NOy = NO + NO2+ NO3+ HNO3+ ClNO+ 2*N2O5+ HNO4) Mechanism proposed by Callis et al. (1991) EEP => NOy => O3

  6. GOES >2MeV

  7. 1987, 60-70 N and S 2D model (Callis, 1997)

  8. UIMESO: Model history MST CCM “UIMESO” ST GCM/PC 24L (50 km) 40L (105 km)

  9. UIMESO: what is inherited • Horizontal grid: 4o latitude by 5o longitude • Dynamical core (FD) • Representation of the surface and tropospheric processes • Chemical solver (implicit Newton-Raphson) • Advective transport (Hybrid scheme)

  10. UIMESO: what is new (1) • Model top at 105 km ( 40 layers in vertical direction) • Non-orographic GWD according to Alexander and Dunkerton (1999) • Solar heating due to oxygen absorption • Chemical heating due to 7 reactions (Mlynczak and Solomon, 1993) • Heating efficiency for Hartley and Ly- bands (Mlynczak and Solomon, 1993) • NonLTE parameterization of Fomichev et al., 1998

  11. UIMESO: what is new (2) • Photolysis rates for Ly-, Schumann-Runge continuum • NO photolysis according to Minschwaner and Siskind, (1993) • Several new reactions • Updated reaction coefficients and absorption cross-sections (JPL-2000 and recent papers) • Additional NOx and HOx source due to EEP events • NOx and HOx fluxes from the thermosphere

  12. Experimental set-up Control run Experiment • Two 10-year long run: • SST/SI from AMIP climatology • No NOy source from EEP • NOy source from EEP for 1987

  13. Annual changes Rozanov et al (2006)

  14. Rozanov et al (2006)

  15. GOES >2MeV

  16. Hood (2002) Rozanov et al (2006) Rozanov et al (2005)

  17. Problems • Too intensive downward motions, too high NOy for EEP run, too low CH4, H2O and ozone in winter time over high-latitudes • Too high NOx and too low ozone in the stratosphere due to probably overestimated O1D production • Weak GWD from Alexander and Dunkerton (1999) parameterization • Warm mesopause, absence of westerly winds in the MLT region in summer

  18. Problems • 2D e- ==> NOy • Non-LTE • QBO

  19. Conclusions • The electrons have significant effects on the ozone, temperature and dynamics in the stratosphere. • Tropospheric changes are observed as well • The reasons why for EEP run CCM overloads the stratosphere with NOy are not clear • New runs with strong GWD are necessary

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