University of Illinois, Urbana-Champaign, USAPMOD/WRC, SwitzerlandNASA/Goddard Space Flight Center, USAUniversity of Michigan, Ann Arbor, USAMain Geophysical Observatory, Russia

ELECTRON PRECIPITATION EFFECTS ON CHEMICAL COMPOSITION AND CLIMATE

E. Rozanov, L. Callis, E. Rozanov, L. Callis,

M. Schlesinger, F. Yang, M. Schlesinger, F. Yang,

N. AndronovaN. Andronova and V. Zubov and V. Zubov

Outline

• Motivation

• Experimental set-up

• Results

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

Hood (2002)

Ozone (%), Solar max - Solar min

Rozanov et al 2005

EEP => NOy => O3

NOy = NO + NO2+ NO3+ HNO3+ ClNO+ 2*N2O5+ HNO4)(

Mechanism proposed by Callis et al. (1991)

1362

1363

1364

1365

1366

1367

1368

1369

0

2 108

4 108

6 108

8 108

1 109

1,2 109

1975 1980 1985 1990 1995 2000 2005

ACRIM3_solar_irr

GOES >2MeV

1987, 60-70 N and S

2D model (Callis, 1997)

UIMESO: Model history

ST GCM/PC MST CCM“UIMESO”24L (50 km)40L (105 km)

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)

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

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

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

Annual changes

Rozanov et al (2006)

Rozanov et al (2006)

1362

1363

1364

1365

1366

1367

1368

1369

0

2 108

4 108

6 108

8 108

1 109

1,2 109

1975 1980 1985 1990 1995 2000 2005

ACRIM3_solar_irr

GOES >2MeV

Rozanov et al (2006)

Rozanov et al (2005)

Hood (2002)

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

Problems

• 2D e- ==> NOy• Non-LTE • QBO

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