Impact of solar UV variability on sudden stratospheric warming

with LMDz-Reprobus

A. Hauchecorne1, S. Bekki1, M. Marchand1, C. Claud2, P. Keckhut1, F. Lefèvre1, D. Cugnet1, S. Lefebvre1, F. Lott2,

G. Thuillier1

• LATMOS, CNRS, UVSQ, UPMC• Laboratoire de Météorologie Dynamique, CNRS, UPMC, Ecole

Polytechnique

Sun-atmosphere link:possible mechanisms

Total solar irradiance: change surface and tropospheric temperature

Solar UV: O3 production stratospheric temperature change in atmospheric circulation: amplification mechanism ?

Particle precipitations (SPE, GCR, EPP)- SPE and EPP in auroral zone: NOx and HOx atmospheric

chemistry- GCR modulated by solar wind:

condensation nuclei cloudsatmospheric chemistry chemistry

J. McCormack, 2004

Sudden Stratospheric Warming

Dynamics and transport LMDz: • Extended version of the LMDz 4th generation GCM (Lott et al.)• Tropospheric version largely used in the french community• LMDz is the atmospheric component of the IPSL Earth System model

(Dufresne et al.)

Chemistry Reprobus:• Chemistry-transport model (Lefèvre et al.)• Chemical families Ox, NOx, HOx, ClOx, BrOx et CHOx chemistry.• Heterogeneous reactions: on aerosols and PSC particles• PSC sedimentation (dehydration and denitrification) : irreversible vertical

transfer of HNO3 and H2O

CCM LMDz-Reprobus

LMDZ-Reprobus Meteorological analysis ERA40

Zonal mean temperature

LMDz-Reprobus 30 years simulations: Minimum and maximum solar conditions

for the 11-year solar cycle

All the other forcings are kept constant: SSTs, sea ice, stratospheric aerosols, CFCs, GHGs

Difference in polar temperature (K)

MIN

MAX

DIF

90°S 90°N

LMDz-Reprobus solar max – solar min

January

Temperature

February

Wind

LMDz Reprobus solar max – solar min

Temperature

Ozone

Stratosphere-troposphere dynamical coupling

From Baldwin and Dunkerton, JASTP, 2005

Conclusion

The solar UV variability mechanism has been tested in LMDz-ReprobusThere is an impact onstratospheric dynamics (sudden stratospheric warming)

Future plans- Impact on the troposphere - Comparison with other models CMAM, SOCOL, IGCM-FASTOC- Common work on the evaluation of different solar forcings

(TSI, UV, GCR, SPE, EEP)