1. 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 2 School of Chemistry, University of Leeds Acknowledgments: Dan Marsh 3, Diego Janches 4, Sandip Dhomse 1, Sarah Broadley 2 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 Mesosphere Stratosphere Troposphere Thermosphere Tropopause Stratopause Mesopause Stratospheric Ozone Layer Meteoric Metals (Na, Fe, Mg, Ca, etc.) Layer

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) 4 o x5 o and 1.9 o x2 o 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 (O x, HO x,ClO x, BrO x etc.)) Ion Chemistry and other parameters……

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

8. WACCM Chemistry Long-lived Species: (19 species) Misc:CO 2, CO, CH 4, H 2 O, N 2 O, H 2, O 2 CFCs: CCl 4, CFC-11, CFC-12, CFC-113 HCFCs: HCFC-22 Chlorocarbons:CH 3 Cl, CH 3 CCl 3, Bromocarbons: CH 3 Br Halons: H-1211, H-1301 Constant Species:N 2, N( 2 D) Short-lived Species: (31-species) O X : O 3, O, O( 1 D) NO X :N, NO, NO 2, NO 3, N 2 O 5, HNO 3, HO 2 NO 2 ClO X :Cl, ClO, Cl 2 O 2, OClO, HOCl, HCl, ClONO 2, Cl 2 BrO X :Br, BrO, HOBr, HBr, BrCl, BrONO 2 HO X :H, OH, HO 2, H 2 O 2 HC Species:CH 2 O, CH 3 O 2, CH 3 OOH 13 Additional Surface Source Gases (NHMCs): CH 3 OH, C 2 H 6, C 2 H 4, C 2 H 5 OH, CH 3 CHO, C 3 H 8, C 3 H 6, CH 3 COCH 3, C 4 H 8, C 4 H 8 O, C 5 H 8, C 5 H 12, C 7 H 8, C 10 H 16 ~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 Updated from R.G. Robel, D. Kinnison (NCAR)

9. 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 NaHCO 3 back to Na 3) Na layer is sensitive to perturbation in the odd oxygen photochemistry and plasma density Plane (ACP, 2004) Ion Chemistry

10. Iron Chemistry in the Upper Atmosphere Plane (Chem. Rev., 2003) 1)Different between metal chemistry (e.g, Fe, Mg, Ca) in MLT. 2) Fe + is not chemically inert 3) The removal of Fe metal atoms involves oxidation by O 3 to form neutral metal oxides, followed by recombination with O 2, CO 2, or H 2 O to form the trioxide, carbonate, or dihydroxide, respectively 4) FeOH is the major iron reservoir below the peak of Fe layer

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

13. Na Injection Rate Three different Na injection rates used in WACCM for testing the model performance Na flux is ~2100 atom cm -2 s -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. WACCM Temperature Comparison WACCM fails to capture the observed T seasonal variation Gardner et al. (To be submitted JGR)

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