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WACCM Studies of Mesospheric Metal Chemistry

WACCM Studies of Mesospheric Metal Chemistry. Wuhu Feng 1,2 Acknowledgments: John Plane 1 ,Martyn Chipperfield 3 ,Dan Marsh 4 ,Diego Janches 5 , Erin Dawkins 1,2 , Josef Hoffner 5 , Fan Yi 6 , Chester Gardner 7 , Jonathan Friedman 8 ,Jonas Hedin 9.

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WACCM Studies of Mesospheric Metal Chemistry

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  1. 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 Science SCHOOL OF EARTH AND ENVIRONMENT

  2. Outline Introduction Mesospheric Metal layers WACCM model Results Summary Future work

  3. Atmospheric Layers Thermosphere Meteoric Metals (Na, Fe, Mg, Ca, K, Si, Ti etc.) Layer Mesopause Mesosphere Stratopause Stratospheric Ozone Layer Stratosphere Tropopause Troposphere

  4. Layers of metals atoms Plane (2011) Concentration cm-3 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!

  5. Processes Ablations (Source) Aurora Tides PMCs PSCs Photolysis MLT Metals Radiation Clouds Chemistry Dynamics Aerosol Deposition circulations, gravity waves etc. Emissions

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

  7. An example of ablation profiles • Ablation- • high velocity collisions with atmospheric molecules lead to rapid heating, melting and evaporation when particles enter the earths atmosphere • Different metals are released at different altitudes • The deposition varies with mass, SZA and velocity Ablation profiles from 1D CABMOD model(SZA=35o,V=21 km/s, mass=4µg).

  8. Metal Chemistry-Fe example Meteoric ablation injects metal atoms and ions; Neutral/ion-molecules chemistry Metal atoms charge exchange Metal atoms oxidisation Metal reservior species Plane (2003)

  9. Sodium Chemistry in the Upper Atmosphere Ionization of Na by charge transfer with the ambient ions in the lower E region. 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 Na layer is sensitive to perturbation in the odd oxygen photochemistry and plasma density Ion Chemistry Plane (ACP, 2004)

  10. Magnesium Chemistry in MLT Mg is one of the most abundance of Metals in the MLT Unlike 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=1.5-10 Na+/Na=0.2 Ca+/Ca=2 Mg+ is not significant depleted relative to other metals in the MLT Plane and Whalley (J. Phys. Chem. A., 2012)

  11. Atmosphere large-scale circulation

  12. 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……

  13. WACCM Performance for the MLT region

  14. Electron Density

  15. PMCs comparison (SOFIE and WACCM) Hervig et al. (2009, JASTP)

  16. WACCM Chemistry 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 Long-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

  17. Meteoric Input function of Fe Feng et al. (JGR, in revision) Total input is ~ 2.2 tonnes/day • Minimum springtime and maximum autumn MIF of Fe • The 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

  18. 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 layer • Satisfactory simulations of Fe by model Feng et al. (JGR, in revision)

  19. Annual mean Fe for other stations

  20. Fe+ profile comparison with Rocket data

  21. Fe+ profile comparison with Rocket data

  22. Fe Seasonal variations Fe peak layer Model simulates the mid-latitude Fe layer quite well • Seasonal variation of Fe density with an early wintertime maximum and summertime minimum

  23. SH High latitude

  24. South Pole

  25. South Pole

  26. 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)

  27. Potassium Comparison

  28. Calcium

  29. Calcium at Kuhlungsborn

  30. Other Metal simulations

  31. Tidal Influences on the metal layer

  32. Gravity Wave impact on Fe layer

  33. Gravity Wave impact on Fe layer for SP

  34. SSW impacts on mesospheric metal layers

  35. Fe

  36. Solar Cycle Impact and trend (K and T)

  37. Other metals

  38. Tropical T and K anomaly

  39. Mid-latitude T and K anomaly

  40. High-latitude T and K anomaly

  41. 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.

  42. 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)

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