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Institute for Climate and Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT

Institute for Climate and Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT. Incorporating Mesospheric Metal Chemistry into NCAR WACCM Model. Wuhu Feng 1,2 , John Plane 2 , Martyn Chipperfield 1 1 IAS, School of Earth and Environment, University of Leeds

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Institute for Climate and Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT

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  1. Institute for Climate and Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT Incorporating Mesospheric Metal Chemistry into NCAR WACCM Model Wuhu Feng1,2, John Plane2, Martyn Chipperfield1 1 IAS, School of Earth and Environment, University of Leeds 2 School of Chemistry, University of Leeds Acknowledgments: Dan Marsh3, Diego Janches4, Sandip Dhomse1, Sarah Broadley2 3 Atmospheric Chemistry Division, NCAR, USA 4 Northwest Research Associates, Boulder, USA

  2. OUTLINE • Motivation • Description of WACCM CCM • Metal Chemistry in Mesosphere • Preliminary Results • Summary • Future work

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

  4. Why We Care About Mesosphere • Studying Climate Change also needs to consider Mesopshere • (impact of climate change by interacting with Stratosphere • and Thermosphere?) • Weather forecast has significant improved by extension of • ECMWF from Stratosphere to Mesosphere • Observations shows pronounced cooling in Mesosphere ( ~2-10K/decade) (Beig et al., 2003) • Mesosphere is poorly understood • ~ 50 tonnes of meteors enters the atmosphere/day(Plane, 2003) • Mesospheric metal layers should be useful for testing the model(s)’ chemical and dynamics processes

  5. Mesospheric Temperature Trend Beig et al. (Rev. Geophys., 2003)

  6. Whole Atmosphere Community Climate Model uses the software • framework of the NCAR CCSM • 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……

  7. WACCM Tracer Transport Scheme Physics FV: No explicit diffusion (besides divergence damping) From Christiane Jablonowski

  8. 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 etc. ) in the standard WACCM model 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 Updated from R.G. Robel, D. Kinnison (NCAR)

  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. Iron Chemistry in the Upper Atmosphere Different between metal chemistry (e.g, Fe, Mg, Ca) in MLT. Fe+ is not chemically inert The removal of Fe metal atoms involves oxidation by O3 to form neutral metal oxides, followed by recombination with O2, CO2, or H2O to form the trioxide, carbonate, or dihydroxide, respectively FeOH is the major iron reservoir below the peak of Fe layer Plane (Chem. Rev., 2003)

  11. Metal Source in the MLT • The Major source of Metals (Na, Fe, Ca, Mg, Si, Al, Ti, K) in the MLT is the ablation of Sporadic Meteoroid particles • Large uncertainty in the daily meteoroids entering the atmosphere (~7-240 tons per day) (Plane, 2004) • Meteoroid particles undergo frictional heating at high velocity (11-72 km/s) when it collides with atmospheric molecules causing metallic species to ablate from the meteoroid surface • Meteoric input function is therefore important to model the Metal in the Mesosphere • Distributions of the particles vary with mass, entry velocity and solar zenith angle Pictures from internet

  12. An example of ablation profiles • Different metals are released at different altitudes • The deposition for the most probable meteoroid varies with mass, SZA and entry velocity The ablation profiles from 1D CAMOD model(SZA=35o,V=21 km/s, mass=4µg).

  13. Na Injection Rate Three different Na injection rates used in WACCM for testing the model performance Na flux is ~2100 atom cm-2s-1

  14. Na Total Column Density Comparison • 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 COSPAR reference Atmosphere (Plane,2010)

  15. Meteoric Input Function (MIF) MIF of individual element by integration of meteoroid particles over ranges of mass, velocity and SZA. Too small flux needed by WACCM?

  16. Sodium (Na) Comparison WACCM with Na chemistry underestimates the observed Na profiles, due to much lower Na flux input into the model(?)

  17. Iron (Fe) Comparison WACCM with Fe chemistry underestimates the observed Fe profiles but fails to capture the seasonal variation due to (WACCM) T problem?

  18. Temperature Comparison • WACCM Gardner et al. (To be submitted JGR) WACCM fails to capture the observed T seasonal variation

  19. Temperature Comparison Metal chemistry in the upper atmosphere seems to affect the atmospheric dynamics in WACCM

  20. Temperature Difference Metal chemistry in the upper atmosphere seems to affect the atmospheric dynamics in WACCM

  21. Summary and Conclusion • Successful adding Mesospheric Metal(s) Chemistry into a 3D NCAR WACCM model • The modelled metal in the MLT is very sensitive to the meteoroid injection rate • Metal chemistry in the upper atmosphere seems to affect the atmospheric dynamics in WACCM (is it real or due to the model internal variability?)

  22. Further Work • Investigate the MIF used in WACCM • Nudged WACCM and higher vertical resolution (~ 1km) run • Need to do similar for other metals (e.g., Ca, Mg etc) • Long-term simulations, compare with available observations • Needs more mesospheric metals observations from Satellites /lidar measurements (SCIAMACHY, ODIN etc) to compare with WACCM which we have included mesospheric Metal chemistry

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