WACCM Studies of Mesospheric Metal Chemistry

Wuhu Feng1,2

Acknowledgments:

John Plane1,Martyn Chipperfield3,Dan Marsh4,Diego Janches5 , Erin Dawkins1,2, Josef Hoffner5, Fan Yi6, Chester Gardner7 , Jonathan Friedman8 ,Jonas Hedin9

Institute for Climate and Atmospheric ScienceSCHOOL OF EARTH AND ENVIRONMENT

Outline

1) Introduction2) Mesospheric Metal layers3) WACCM model4) Results5) Summary 6) Future work

Atmospheric Layers

Mesosphere

Stratosphere

Troposphere

Thermosphere

Tropopause

Stratopause

Mesopause

StratosphericOzone Layer

MeteoricMetals (Na,Fe, Mg, Ca, K, Si, Ti etc.) Layer

Layers of metals atoms

Plane (2011)

Questions: Sources? Useful tracers of dynamic processes (i.e., gravity waves, tides)? Impact on stratosphere/troposphere? Solar cycle impacts? It requires detailed processes controlling the metal layers!

Concentration cm-3

MLTMetals

Radiation

Chemistry

Photolysis

ProcessesAblations (Source)

Dynamics

Aurora

PMCs

PSCs

Clouds

circulations, gravity waves etc. EmissionsDeposition

Aerosol

Tides

Multi-scale Modelling of Mesospheric Metals (4M) project

An example of ablation profiles

Ablation profiles from 1D CABMOD model(SZA=35o,V=21 km/s, mass=4µg).

Ablation-high velocity collisions with atmospheric molecules lead to rapid heating, melting and evaporation when particles enter the earths atmosphereDifferent metals are released at different altitudes The deposition varies with mass, SZA and velocity

Metal Chemistry-Fe example

Plane (2003)

Meteoric ablation injects metal atoms and ions;

Neutral/ion-molecules chemistry

Metal atoms oxidisation

Metal atoms charge exchange

Metal reservior species

Sodium Chemistry in the Upper Atmosphere

1) Ionization of Na by charge transfer with the ambient ions in the lower E region.

2) The Na layer appears in the upper mesosphere due to the dramatic increase in atomic oxygen and hydrogen above 80 km which convert NaHCO3 back to Na

3) Na layer is sensitive to perturbation in the odd oxygen photochemistry and plasma density

Plane (ACP, 2004)

Ion Chemistry

Magnesium Chemistry in MLTMg is one of the most abundance of Metals in the MLTUnlike other Meteoric metals (Fe, Na, K and Ca), neight Mg/Mg+ can be observed by ground-based lidar (laser radar) as they have resonance transitions in the UV reagion at 285 and 280 nm where light is strongly absorbed by stratospheric.Mg+ is produced from Mg by photoionization and charge transfer with NO+ and O+ (dominant ions in the LT)Mg+/Mg=1.5-10Na+/Na=0.2Ca+/Ca=2Mg+ is not significant depleted relative to other metals in the MLT

Plane and Whalley (J. Phys. Chem. A., 2012)

Atmosphere large-scale circulation

• Whole Atmosphere Community Climate Model uses the software

framework of the NCAR CESM

• Atmospheric layers coupling,processes,climate variability/change

• σ-p coordinates (66 levels) from surface up to 140 Km

(~1.5 km in LS and ~3 km in MLT)

• 4ox5o and 1.9ox2o horizontal resolution

• Detailed dynamics/physics in the Troposphere/Stratosphere/

Mesosphere/Thermosphere (Finite-Volume dynamics Core)

• Detailed Chemical processes in the atmosphere (using NCAR

MOZART-3 chemistry package (Ox, HOx,ClOx, BrOx etc.))

• Ion Chemistry and other parameters……

WACCM Performance for the MLT region

Electron Density

PMCs comparison (SOFIE and WACCM)

Hervig et al. (2009, JASTP)

WACCM ChemistryLong-lived Species: (19 species)

Misc: CO2, CO, CH4, H2O, N2O, H2, O2

CFCs: CCl4, CFC-11, CFC-12, CFC-113

HCFCs: HCFC-22

Chlorocarbons: CH3Cl, CH3CCl3,

Bromocarbons: CH3Br

Halons: H-1211, H-1301

Constant Species: N2 , N(2D)

Short-lived Species: (31-species)

OX: O3, O, O(1D)

NOX: N, NO, NO2, NO3, N2O5, HNO3, HO2NO2

ClOX: Cl, ClO, Cl2O2, OClO, HOCl, HCl, ClONO2, Cl2

BrOX: Br, BrO, HOBr, HBr, BrCl, BrONO2

HOX: H, OH, HO2, H2O2

HC Species: CH2O, CH3O2, CH3OOH

13 Additional Surface Source Gases (NHMCs): CH3OH, C2H6, C2H4, C2H5OH, CH3CHO, C3H8, C3H6, CH3COCH3, C4H8, C4H8O, C5H8, C5H12, C7H8, C10H16

~45 Additional radical species

Detailed 3D emission inventories of natural and anthropogenic surface sources;

Dry/Wet deposition of soluble species

Lightning and Aircraft production of NOx

12 Heterogeneous processes, 71 photolysis reactions, 183 gas phase reactions

No Metal Chemistry (e.g., Na, Fe, Ca, Mg, K, Si, etc. ) in the standard WACCM model, but now includes in WACCM

Meteoric Input function of Fe

Minimum springtime and maximum autumn MIF of FeThe annual mean MIF used in the model is 9414 atoms cm-2s-1

Note large range of MIF (4300-38000 atoms cm-2s-1) used in previous Fe 1D models simulations for different locations

Total input is ~ 2.2 tonnes/day

Feng et al. (JGR, in revision)

Annual mean Fe and other species (40N)

Fe+ ions dominate on the top-side of the Fe layer(FeOH)2, FeOH and Fe(OH)2 are the dominant reservoirs on the underside of the layerSatisfactory simulations of Fe by model

Feng et al. (JGR, in revision)

Annual mean Fe for other stations

Fe+ profile comparison with Rocket data

Fe+ profile comparison with Rocket data

Fe Seasonal variations

Seasonal variation of Fe density with an early wintertime maximum and summertime minimum

Fe peak layer

Model simulates the mid-latitude Fe layer quite well

SH High latitude

South Pole

South Pole

Na Total Column Density

Constructing Mesospheric Na reference by combination of recent satellite observations (ie. OSIRIS/Odin) and ground-based lidar measurements by Plane (2010).

Successful input Na chemistry in WACCM model

Detailed MIF needed though there is good agreement between observations and model

Marsh et al. (JGR, submitted)

Potassium Comparison

Calcium

Calcium at Kuhlungsborn

Other Metal simulations

Tidal Influences on the metal layer

Gravity Wave impact on Fe layer

Gravity Wave impact on Fe layer for SP

SSW impacts on mesospheric metal layers

Fe

Solar Cycle Impact and trend (K and T)

Other metals

Tropical T and K anomaly

Mid-latitude T and K anomaly

High-latitude T and K anomaly

Summary and Conclusions

Successful adding Mesospheric metal Chemistry (Na, Fe, K, Ca, Mg) into a 3D NCAR CESM (WACCM4) model ----The first global model of meteoric metals

Overall, WACCM with Fe/Na chemistry gives good simulation compared with Lidar/Satellite measurements.

Investigating different MLT metal layers within the same model will thus allow us to better understand the astronomy, chemistry and transport processes that control the different metal layers in the MLT.

Ongoing Work

Cosmic dust in the terrestrial atmosphere (CODITA project)

NOx and HOx production by energetic electrons and impacts on polar stratospheric ozone (NOHO project)