The Penetration of Solar Storm Effects into the Earth's Atmosphere Maura Hagan and Ray Roble Gang Lu, Jens Oberheide*, Stan Solomon, Art Richmond National Center for Atmospheric Research Scott Bailey (U AK), Gonzalo Hernandez (U AK), Charles Jackman (GSFC), Scott Palo (CU), Dennis Riggin (CoRA), James Russell (Hampton U) *now at University of Wuppertal

The Overarching Question: How deep into the Earth’s atmosphere do the effects of solar and geomagnetic activity penetrate? modeler’s perspective on April 2002 events focus on the response of the neutral gas  lower thermosphere mesosphere stratosphere

Caution: Solar radiative forcing decreases as geomagnetic activity increases during the storm period How deep into the atmosphere do the effects of geomagnetic activity penetrate?

Part I Atmospheric Nomenclature   mesopause region characteristics The TIME-GCM April 2002 Simulation Select Results  direct  direct penetration  geomagnetic activity  lower thermosphere auroral heating; nitric oxide density [NO] ; radiational cooling; temperature change  direct  direct penetration  solar particle event  stratosphere & mesosphere ionization rate; [NO]; ozone density [O 3 ]

Temperature Structure of Earth’s Atmosphere Tropo (Greek: tropos); “change” Lots of weather Strato (Latin: stratum); Layered Meso (Greek: messos); Middle Thermo (Greek: thermes); Heat Exo (greek: exo); outside

The Periodic Absorption of Solar Radiation Excites Atmospheric Tides troposphere stratosphere mesosphere thermosphere ~90km ~15km ~30km O3O3 O3O3 O2O2 O Extreme UltraViolet Schumann-Runge Bands & Continuum UltraViolet H2OH2O H2OH2O

Part I Atmospheric Nomenclature   mesopause region characteristics The TIME-GCM April 2002 Simulation Select Results  direct  direct penetration  geomagnetic activity  lower thermosphere auroral heating; nitric oxide density [NO] ; radiational cooling; temperature change  direct  direct penetration  solar particle event  stratosphere & mesosphere ionization rate; [NO]; ozone density [O 3 ]

The Simulation Period

AMIE THE NCAR AMIE hermosphere Thermosphere onosphere Ionosphere esosphere Mesosphere lectrodynamics Electrodynamics - eneral General irculation Circulation odel Model SIMULATION 1st Principles Calculation Resolution: horizontal - 5 o x 5 o vertical - 2 grid points /scale height 2-minute time step oweroundaryonditions:LowerBoundaryConditions: lobalcaleaveodel G lobal- S cale W ave M odel tidal perturbations NO ationalenter for NO N ational C enter for nvironmentalredictions E nvironmental P redictions planetary wave activity pperoundaryonditions:UpperBoundaryConditions: Radiative forcing - F 10.7 Proxy AMIE AMIE - Particles & Electrodynamics

TIME-GCM/AMIE Simulation Inputs* * *

Part I Atmospheric Nomenclature   mesopause region characteristics The TIME-GCM April 2002 Simulation Global Effects Select Results - Global Effects  direct  direct penetration  geomagnetic activity  lower thermosphere auroral heating; nitric oxide density [NO] ; radiational cooling; temperature change  direct  direct penetration  solar particle event  stratosphere & mesosphere ionization rate; [NO]; ozone density [O 3 ]

Zonal Mean Auroral Energy Input Heating Efficiency: ~30% mW/m 2 ~90 km ~110 km* ~150 km ~250 km mesopause region lower thermosphere upper thermosphere April 17,2002

Northern Hemispheric Warming near 110 km April 17 UT=0 ….before major onset Auroral Energy Flux  Nitric Oxide Density Enhancements Radiational Cooling Changes  Auroral Heating   +++ dynamics +++  temperature

Northern Hemispheric Warming near 110 km April 17 UT=20 ….during major storm Auroral Energy Flux  Nitric Oxide Density Enhancements Radiational Cooling Changes  Auroral Heating   +++ dynamics +++  temperature

Part I Atmospheric Nomenclature   mesopause region characteristics The TIME-GCM April 2002 Simulation Local Effects Select Results - Local Effects  direct  direct penetration  geomagnetic activity  lower thermosphere auroral heating; nitric oxide density [NO] ; radiational cooling; temperature change  direct  direct penetration  solar particle event  stratosphere & mesosphere ionization rate; [NO]; ozone density [O 3 ]

GOES-8 Proton Flux April 21-23, 2002 stratosphere mesosphere Produce NO x & HO x  Affects O 3

TIME-GCM Ionization Rates over Antarctica …with-without solar protons 

Composition Changes over Antarctica …from TIME-GCM results with & without solar protons % change [NO+NO 2 ] % change [O 3 ] deeper and longer-lived 