1G: CAM-chem and WACCM in chemistry-climate model intercomparison

CAM-chem and WACCM participated in the chemistry-climate model intercomparison project:

CAM-chem contributed also to the Global and regional assessment of intercontinental transport of air pollution: results from HTAP, AQMEII and MICS

The production of several long-term climate simulations by both CESM CAM-chem and WACCM resulted in 30 papers (22 CCMI and 8 HTAP2) that have been published, or are in review, with one or more NCAR co-authors between Oct 2017 and Sep 2018. Both WACCM and CAM-chem performed very well compared to other chemistry-climate models with regard to various quantities, including tropospheric and stratospheric chemistry, aerosols, and dynamics. These comparisons also helped to identify shortcomings that will be focus of future developments. For example Revell et al. (2018) compared tropospheric ozone from many models to observations (Figure 1). CAM-chem and WACCM were among the best models, showing the smallest bias.

Deviations of tropospheric ozone from various models.
Figure 1: Deviations of tropospheric ozone from various models participating in the CCMI project from satellite observations [Revell et al., 2018]. Click for larger image.

CESM2 WACCM will also be participating in the CMIP6 and related model intercomparison projects. In the last fiscal year, a lot of work has been done by the WACCM and CAM-chem teams to produce a running and well performing model with comprehensive chemistry and realistic dynamics. Work included tuning and testing the models, as well as producing emissions, lower boundary datasets, and a volcanic sulfur dataset. Many climate models participating in CMIP6 do not include interactive chemistry and must rely on prescribed chemistry and aerosols fields provided from other models.  We have run WACCM4 (the version used for CCMI) with CMIP6 emissions to produce these fields for use by the international community, as shown in Figure 2.

Land and sea-surface temperature evolution of WACCM4 simulations.
Figure 2: Land and sea-surface temperature evolution of WACCM4 simulations performed with CMIP6 emissions and lower boundary conditions to produce chemical fields for the community.


  1. Revell, L. E., Stenke, A., Tummon, F., Feinberg, A., Rozanov, E., Peter, T., Abraham, N. L., Akiyoshi, H., Archibald, A. T., Butchart, N., Deushi, M., Jöckel, P., Kinnison, D., Michou, M., Morgenstern, O., O'Connor, F. M., Oman, L. D., Pitari, G., Plummer, D. A., Schofield, R., Stone, K., Tilmes, S., Visioni, D., Yamashita, Y., and Zeng, G.: Tropospheric ozone in CCMI models and Gaussian process emulation to understand biases in the SOCOLv3 chemistry–climate model, Atmos. Chem. Phys., 18, 16155-16172, https://doi.org/10.5194/acp-18-16155-2018, 2018.

  2. Dong, X., Fu, J. S., Zhu, Q., Sun, J., Tan, J., Keating, T., Sekiya, T., Sudo, K., Emmons, L., Tilmes, S., Jonson, J. E., Schulz, M., Bian, H., Chin, M., Davila, Y., Henze, D., Takemura, T., Benedictow, A. M. K., and Huang, K.: Long-range transport impacts on surface aerosol concentrations and the contributions to haze events in China: an HTAP2 multi-model study, Atmos. Chem. Phys., 18, 15581-15600, https://doi.org/10.5194/acp-18-15581-2018, 2018.

  3. Tan, J., Fu, J. S., Dentener, F., Sun, J., Emmons, L., Tilmes, S., Flemming, J., Takemura, T., Bian, H., Zhu, Q., Yang, C.-E., and Keating, T.: Source contributions to sulfur and nitrogen deposition – an HTAP II multi-model study on hemispheric transport, Atmos. Chem. Phys., 18, 12223-12240, https://doi.org/10.5194/acp-18-12223-2018, 2018.

  1. Liang, C.-K., West, J. J., Silva, R. A., Bian, H., Chin, M., Davila, Y., Dentener, F. J., Emmons, L., Flemming, J., Folberth, G., Henze, D., Im, U., Jonson, J. E., Keating, T. J., Kucsera, T., Lenzen, A., Lin, M., Lund, M. T., Pan, X., Park, R. J., Pierce, R. B., Sekiya, T., Sudo, K., and Takemura, T., 2018: HTAP2 multi-model estimates of premature human mortality due to intercontinental transport of air pollution and emission sectors, Atmos. Chem. Phys., 18, 10497-10520, doi:10.5194/acp-18-10497-2018.

  2. Turnock, S. T., Wild, O., Dentener, F. J., Davila, Y., Emmons, L. K., Flemming, J., Folberth, G. A., Henze, D. K., Jonson, J. E., Keating, T. J., Kengo, S., Lin, M., Lund, M., Tilmes, S., and O'Connor, F. M.: The impact of future emission policies on tropospheric ozone using a parameterised approach, Atmos. Chem. Phys., 18, 8953-8978, https://doi.org/10.5194/acp-18-8953-2018, 2018.

  3. Tan, J., Fu, J. S., Dentener, F., Sun, J., Emmons, L., Tilmes, S., Sudo, K., Flemming, J., Jonson, J. E., Gravel, S., Bian, H., Davila, Y., Henze, D. K., Lund, M. T., Kucsera, T., Takemura, T., and Keating, T., 2018: Multi-model study of HTAP II on sulfur and nitrogen deposition, Atmos. Chem. Phys., 18, 6847-6866, https://doi.org/10.5194/acp-18-6847-2018.

  4. Huang, M., Carmichael, G. R., Pierce, R. B., Jo, D. S., Park, R. J., Flemming, J., Emmons, L. K., Bowman, K. W., Henze, D. K., Davila, Y., Sudo, K., Jonson, J. E., Tronstad Lund, M., Janssens-Maenhout, G., Dentener, F. J., Keating, T. J., Oetjen, H., and Payne, V. H., 2017: Impact of intercontinental pollution transport on North American ozone air pollution: an HTAP phase 2 multi-model study, Atmos. Chem. Phys., 17, 5721-5750, doi:10.5194/acp-17-5721-2017.

  5. Dhomse, S et al., Estimates of ozone return dates from Chemistry-Climate Model Initiative simulations, Atmos. Chem. Phys., 18, 8409-8438, https://doi.org/10.5194/acp-18-8409-2018, 2018.

  6. Meehl, G. A., Tebaldi C.,  Tilmes, S., Lamarque J.-F., Bates S., Pendergrass A., and Lombardozzi D.: Future heat waves and surface ozone, Environmental Research Letters, Volume 13, Number 6, doi:10.1088/1748-9326/aabcdc, 2018.

  7. Orbe, C., H. Yang, D. W. Waugh, G. Zeng, O. Morgenstern, D. E. Kinnison, J-F Lamarque, S. Tilmes, D. A. Plummer, J. F. Scinocca, B Josse, V. Marecal, P. Jockel, L. D. Oman, S. E. Strahan, M. Deushi, T. Y. Tanaka, K. Yoshida, H. Akiyoshi, Y. Yamashita, A. Stenke, L. Revell, T. Sukhodolov, E. Rozanov, G. Pitari, D. Visioni, K. Stone, and R. Schofield, Large-Scale Tropospheric Transport in the Chemistry Climate Model Initiative (CCMI) Simulations, Atmos. Chem. Phys., https://doi.org/10.5194/acp-2017-1038, 2018.

  8. Tan, J., Fu, J. S., Dentener, F., Sun, J., Emmons, L., Tilmes, S., Sudo, K., Flemming, J., Jonson, J. E., Gravel, S., Bian, H., Davila, Y., Henze, D. K., Lund, M. T., Kucsera, T., Takemura, T., and Keating, T.: Multi-model study of HTAP II on sulfur and nitrogen deposition, Atmos. Chem. Phys., 18, 6847-6866, https://doi.org/10.5194/acp-18-6847-2018, 2018.

  9. S. Son et al., Tropospheric jet response to Antarctic ozone depletion: An update with Chemistry-Climate Model Initiative (CCMI) models. Environmental Research Letters, Volume 13, Number 5, doi:10.1088/1748-9326/aabf21, 2018

  10. Anderson, D. C., Nicely, J. M., Wolfe, G. M., Hanisco, T. F., Salawitch, R. J., Canty, T. P., … Zeng, G. (2017). Formaldehyde in the tropical western Pacific: Chemical sources and sinks, convective transport, and representation in CAM‐Chem and the CCMI models. Journal of Geophysical Research: Atmospheres, 122, 11,201–11,226.

  11. Maycock, A., et al., Revisiting the mystery of the recent stratospheric temperature trends, Geophys. Res. Lett., in press, 2018.

  12. GrooB, J-U., R. Muller, R. Spang, I. Tritscher, T. Wegner, M. P. Chipperfield, W. Feng, D. E. Kinnison, and S. Madronich, On the discrepancy of HCl processing in the dark polar vortices, Atmos. Chem. Phys., in press, 2018.

  13. Tao, M., L. L. Pan, P. Konopka, S. B. Honomichi, D. E. Kinnison, E. C. Apel, A Lagrangian Model Diagnosis of Stratospheric Contributions to Tropical Midtropospheric Air,  J. Geophys. Res., doi:10.1029/2018JD028696.

  14. Tweedy, O. V., D. W. Waugh, W. J. Randel, M. Abalos, L. D. Oman, D. E. Kinnison, The Impact of Boreal Summer ENSO Events on Tropical Lower Stratospheric Ozone, J. Geophys. Res, doi:10.1029/2018JD029020.

  15. Wilka, C., K. Shah, K. Stone, S. Solomon, D. Kinnison, M. Mills, A. Schmidt, R. R. Neely III, The Role of Heterogeneous Chemistry in Ozone Depletion and Recovery, Geophys. Res. Lett., doi:10.1029/2018GL078596, 2018.

  16. Lossow, S., D. F. Hurst, K. H. Rosenlof, G. P. Stiller, T. von Clarmann, S. Brinkop, M. Dameris, P. Jockel, D. E. Kinnison, J. Plieninger, D. Plummer, F. Ploeger, W. G. Read, E. E. Remsberg, J. M. Russell, and M. Tao, Can sampling biases explain the discrepancies between lower stratospheric water vapor trend estimates derived from the FPH observations at Boulder and a merged zonal mean satellite data set?, Atmos. Chem. Phys., https://doi.org/10.5194/acp-18-8331-2018.

  17. Cuevas, C. A., N. Maffezzoli, J. P. Corella, A. Spolaor, P. Vallelonga, H. A. Kjaer, M. Simonsen, M. Winstrup, B. Vinther, C. Horvat, R. P. Fernandez, D. Kinnison, J-F Lamarque, A. Saiz-Lopez, Rapid increase in atmospheric iodine levels in the North Atlantic since the mid-20th century, Nature Geos. Sci., DOI: 10.1038/s41467-018-03756-1, 2018.

  18. Tilmes, S., J. H. Richter, M. J. Mills, B. Kravitz, D. G. MacMartin, R. R. Garcia, D. E. Kinnison, J-F Lamarque, J. Tribbia, and F. Vitt,  Effects of Different Stratospheric SO2 Injection Altitudes on Stratospheric Chemistry and Dynamics, J. of Geophys. Res., doi:1002/2017JD028146, 2018.

  19. Wales, et al., Stratospheric injection of brominated very short-lived substances: Aircraft observations in the Western Pacific and representation in global models. J. of Geophys. Res., 123. https://doi.org/ 10.1029/2017JD027978, 2018.

  20. Dietmuller, R. Eichinger, H. Garney, T. Birner, H. Boenish, G. Pitari, E. Mancini, D. Visioni, A. Stenke, L. Revell, E. Rozanov, D. A. Plummer, J. Scinocca, P. Jockel, L. Oman, M. Deushi, S. Kiyotaka, D. E. Kinnison, R. Garcia, O. Morgenstern, G. Zeng, K. A. Stone, R. Schofield, Quantifying the effect of mixing on the mean age of air in CCMVal-2 and CCMI-1 models, Atmos. Chem. Phys.,https://doi.org/10.5914/acp-18-6699-2018.

  21. Stone, K. A., S. Solomon, and D. E. Kinnison, On The Identification of Ozone Recovery, Geophys. Res. Lett., doi:10.1029/2018GL077955, 2018.

  22. Iglesias-Suarez, F., D. E. Kinnison, A. Rap, A. C. Maycock, O. Wild, and P. J. Young, Key drivers of ozone change and its radiative forcing over the 21st century, Atmos. Chem. Phys., https://doi.org/10.5194/acp-18-6121-2018.

  23. Schultz, M., S. Stadtler, S. Schroder, D. Taraborrelli, B. Franco, J. Krefting, A.Henrot, S. Ferrachat, U. Lohmann, D. Neubauer, C. Siegenthaler-Le Drain, S. Wahl, H. Kokkola, T. Kuhn, S. Rast, H. Schmidt, P. Stier, D. Kinnison, G. S. Tyndall, J. J. Orlando, C. Wespes, The Chemistry Climate Model ECHAM-HAMMOZ, Geo. Mod. Dev., , https://doi.org/10.5194/gmd-11-1695-2018.

  24. Koenig, T., K., et al., BrO and Bry profiles over the Western Pacific: Relevance of Inorganic Bromine Sources and a Bry Minimum in the Aged Tropical Tropopause Layer, Atmos. Chem. Phys., https://doi.org/10.5194/acp-17-15245-2017,2018.

  25. Zhang, J., W. Tian, F. Xie, M. P. Chipperfield, W. Feng, S-W Son, N. L. Abraham, A. T. Archibald, S. Bekki, N. Butchart, M. Deushi, S. Dhomse, Y. Han, P. Jockel, D. Kinnison, O. Kirner, M. Michou, O. Morgenstern, F. M. O'Connor, G. Pitari, D. A. Plummer, L. E. Revell, E. Rozanov, D. Visioni, W. Wang, and G. Zeng, Stratospheric ozone loss over the Eurasian continent induced by the polar vortex shift, Nature Comm., 2018.  

  26. Ryan, N. J., D. E. Kinnison, R. R. Garcia, C. G. Hoffmann, M. Palm, U. Raffalski, J., Notholt, Assessing the ability to derive rates of polar middle-atmospheric descent using trace gas measurements from remote sensors, Atmos. Chem. Phys., https://doi.org/10.5194/acp-18-1457-2018.

  27. Checa-Garcia, R., M. I. Hegglin, D. E. Kinnison, D. A. Plummer, and K. P. Shine, Historical Tropospheric and Stratospheric Ozone Radiative Forcing Using the CMIP6 Database, Geophys. Res. Lett., doi:10.1029/2017GL076770, 2018.

  28. Morgenstern, O., H. Akiyoshi, D. E. Kinnison, R. R. Garcia, D. A. Plummer, J. Scinocca, G. Zeng, E. Rozanov, A. Stenke, L. E. Revell, G. Pitari, E. Mancini, G. Di Genova, S. S. Dhomse, and M. P. Chipperfield, Ozone sensitivity to varying greenhouse gases and ozone-depleting substances in CCMI simulations, Atmos. Chem. Phys., 18, 1091-1114, https://doi.org/10.5194/acp-18-1091-2018.

  29. Bandaro, J., S. Solomon, B. D. Santer, D. E. Kinnison, M. J. Mills, Detectability of the Impacts of Ozone Depleting Substances and Greenhouse Gases upon Stratospheric Ozone Accounting for Nonlinearities in Historical Forcings, Atmos. Chem. Phys., https://doi.org/10.5194/acp-18-143-2018.