The Whole Atmosphere Community Climate Model (WACCM)

R.G. Roble NCAR/HAO A.D. Richmond, M.E. Hagan, H. Liu, S. Solomon, B. Foster (NCAR/HAO) R.R. Garcia, D. Kinnison, D. Marsh (NCAR/ACD) B. Boville, F. Sassi (NCAR/CGD)

WACCM Components: A collaboration among 3 NCAR Divisions TIME GCM HAO R. Roble B. Foster Mesospheric + Thermospheric Processes MOZART Chemistry

(currently offline)

ACD R. Garcia D. Kinnison + Dynamics + Physical processes

WACCM

(Middle Atmosphere CCM)

MACCM3 CGD B. Boville F. Sassi

WACCM Components: A collaboration among 3 NCAR Divisions TIME GCM HAO R. Roble B. Foster Mesospheric + Thermospheric Processes MOZART Chemistry

(currently offline)

ACD R. Garcia D. Kinnison + Dynamics + Physical processes

WACCM

(Middle Atmosphere CCM)

MACCM3 CGD B. Boville F. Sassi

WACCM Motivation Roble, Geophysical Monographs,

123

, 53, 2000

•Coupling between atmospheric layers: - Waves transport energy and momentum from the lower atmosphere to drive the QBO, SAO, sudden warmings, mean meridional circulation - Solar inputs, e.g., auroral production of NO in the mesosphere and downward transport to the stratosphere - Stratosphere-troposphere exchange • Climate Variability and Climate Change: - What is the impact of the stratosphere on tropospheric variability, e.g., the Artic oscillation or “annular mode”? - How important is coupling among radiation, chemistry, and circulation? (e.g., in the response to O 3 depletion or CO 2 increase) Jarvis, “Bridging the Atmospheric Divide”

Science

,

293

, 2218, 2001

WACCM Motivation

• Response to Solar Variability: - Recent satellite observations have shown that solar cycle variation is: 0.1% for total Solar Irradiance 5-10% at  200nm - Radiation at wavelengths near 200 nm is absorbed in the stratosphere => Impacts on global climate may be mediated by stratospheric chemistry and dynamics • Satellite observations: - There are several satellite programs that can benefit from a comprehensive model to help interpret observations - e.g., UARS, TIMED, EOS Aura

WACCM and the NCAR Community Climate System Model Atmosphere ICE + LAND WACCM

dynamics, chemistry WACCM uses the

software framework of the NCAR CCSM

. May be run in place of the standard CAM (Community Atmospheric Model)

OCEAN

WACCM Dynamics

Additions to the original MACCM3 code (WACCM1, WACCM1b):

• Parameterization of non-LTE IR (15  m band of CO 2 above 70 km) merged with CCSM IR parameterization (below 70 km) • Short wave heating rates (above 70 km) due to absorption of radiation shortward of 200 nm and chemical potential heating • Gravity Wave parameterization extended upward, includes dissipation by molecular viscosity • Effects of dissipation of momentum and heat by molecular viscosity (dominant above 100 km) • Diffusive separation of atmospheric constituents above about 90 km • Simplified parameterization of ion drag

Under test for interactive WACCM2:

• Finite-volume dynamics for consistency with MOZART transport • Modified cloud water and near-IR parameterizations for more accurate seasonal cycle of temperature at tropopause

WACCM Zonal Mean Wind and Temperature c.i.=10 m/s c.i.=10 K

Gravity waves momentum sources: January

c.i.=0.1 m/s/day c.i.=10 m/s/day

Chemistry Module (MOZART-3)

(50 species; 41 Photolysis, 93 Gas Phase, 17 Hetero. Rx) Our goal was to represent the chemical processes considered important in the: • Troposphere, Stratosphere, and Mesosphere: • Ox, HO x , NO x , ClO x , and BrO x • Heterogeneous processes on sulfate, nitric acid hydrates, and water-ice aerosols • Thermosphere (limited): • Auroral NO x production • Currently do not include ion-molecule reactions

Long-lived Species: – Misc: – CFCs: – HCFCs: – Chlorocarbons: – Bromocarbons: – Halons: – Constant Species: Short-lived Species: O X : NO X : ClO X : BrO X : HO X : HC Species:

WACCM Chemical Species

(17-species, 1-constant) CO 2 , CO, CH 4 , H 2 O, N 2 O, H 2 , O 2 CCl 4 , CFC-11, CFC-12, CFC-113 HCFC-22 CH 3 Cl, CH 3 CCl 3 , CH 3 Br H-1211, H-1301 N 2 (32-species) O 3 , O, O( 1 D) N, N( 2 D), NO, NO 2 , NO 3 , N 2 O 5 , HNO 3 , HO 2 NO 2 Cl, ClO, Cl 2 O 2 , OClO, HOCl, HCl, ClONO 2 , Cl 2 Br, BrO, HOBr, HBr, BrCl, BrONO 2 H, OH, HO 2 , H 2 O 2 CH 2 O, CH 3 O 2 , CH 3 OOH

H

2

O (ppmv) *** July Average

MOZART3 / WACCM1b - 1995 UARS/Clim – HALOE/MLS

H

2

O (ppmv) *** WACCM/MZ3 GHG + ENSO Trend Sim.

Including sea surface temperature and increasing Greenhouse gases.

Total Column Ozone (Dobson Units) Earth Probe TOMS, 1999 (daily) WACCM (daily)

NO

X

(VMR) *** Trend Simulation *** 87N

July 2002 Solar Protons

Diurnal V tide structure - equinox

LATITUDE V from UARS/WINDI (McLandress et al, 1996) LATITUDE

Diurnal V tide structure - solstice

LATITUDE V from UARS/WINDI (McLandress et al, 1996) LATITUDE

Diurnal V tide - annual cycle at 20 N

days V from UARS/WINDI (McLandress et al, 1996)

Diurnal V tide – annual cycle at 20N, 95 km

UARS/HRDI V At 95 km, 20 N (Burrage et al., 1995) WACCM V At 97 km, 18 N maxima at equinoxes deep minima at solstices phase change at summer solstice days days

Tidal contributions due to shortwave and convective heating

In the model, •Shortwave heating excites mainly migrating components • Convective heating excites migrating and non-migrating components Short-wave (O

3

) heating at 50 km Convective heating at 5 km FREQUENCY (cpd)

migrating Diurnal V tide at 98 km (UT = 6) migrating + non-migrating less distortion with weaker non-migrating components longitude migrating + non-migrating symmetrized Q conv longitude presence of non-migrating components distorts diurnal tide longitude

Semidiurnal V tide at 95 km (equinox) model vs. HRDI obs. (Burrage et al., 1995) longitude longitude

Diurnal "non-migrating" tides

k=4 eastward T - March 19 k=4 eastward T - March 29 note Kelvin wave structure LATITUDE

Summary • WACCM interactive chemistry/dynamics • Current version from ground up to 140 km • Next phase introduce auroral processes • Extend model to exosphere, ~500 km • Interactive Ionosphere and Dynamo • Time-dependent forcings from M-I couplings • Past specification from magnetic indicies, AMIE • Future forcasts need some empirical model • Determine how solar, auroral and atmospheric variability interact and how deep into the atmosphere solar influences penetrate.

• Atmosphere/Ionosphere response to global change