University of Illinois, UrbanaChampaign, USA

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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
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Outline

• Motivation
• Experimental set-up
• Results

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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
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Ozone (), Solar max - Solar min
Hood (2002)
Rozanov et al 2005
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(No Transcript)
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Mechanism proposed by Callis et al. (1991)
EEP gt NOy gt O3
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GOES gt2MeV
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1987, 60-70 N and S
2D model (Callis, 1997)
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UIMESO Model history
MST CCM UIMESO
ST GCM/PC
24L (50 km)
40L (105 km)
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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)

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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

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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

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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

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Annual changes
Rozanov et al (2006)
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Rozanov et al (2006)
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GOES gt2MeV
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Hood (2002)
Rozanov et al (2006)
Rozanov et al (2005)
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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

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Problems

• 2D e- gt NOy
• Non-LTE
• QBO

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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