ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-11-10389-2011 Simulating deep convection with a shallow convection scheme Hohenegger C. 1 2 Bretherton C. S. 1 Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA now at: Max Planck Institute for Meteorology, Hamburg, Germany 19 10 2011 11 20 10389 10406 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/11/10389/2011/acp-11-10389-2011.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/10389/2011/acp-11-10389-2011.pdf

Convective processes profoundly affect the global water and energy balance of our planet but remain a challenge for global climate modeling. Here we develop and investigate the suitability of a unified convection scheme, capable of handling both shallow and deep convection, to simulate cases of tropical oceanic convection, mid-latitude continental convection, and maritime shallow convection. To that aim, we employ large-eddy simulations (LES) as a benchmark to test and refine a unified convection scheme implemented in the Single-column Community Atmosphere Model (SCAM). Our approach is motivated by previous cloud-resolving modeling studies, which have documented the gradual transition between shallow and deep convection and its possible importance for the simulated precipitation diurnal cycle. <br></br> Analysis of the LES reveals that differences between shallow and deep convection, regarding cloud-base properties as well as entrainment/detrainment rates, can be related to the evaporation of precipitation. Parameterizing such effects and accordingly modifying the University of Washington shallow convection scheme, it is found that the new unified scheme can represent both shallow and deep convection as well as tropical and mid-latitude continental convection. Compared to the default SCAM version, the new scheme especially improves relative humidity, cloud cover and mass flux profiles. The new unified scheme also removes the well-known too early onset and peak of convective precipitation over mid-latitude continental areas.

 References Arakawa, A.: The cumulus parameterization problem: Past, present, and future, J. Climate, 17, 2493–2525, 2004. Arakawa, A. and Schubert, W. H.: Interaction of a cumulus cloud ensemble with large-scale environment, Part 1, J. Atmos. Sci., 31, 674–701, 1974. Bechtold, P., Chaboureau, J. P., Beljaars, A., Betts, A. K., Kohler, M., Miller, M., and Redelsperger, J. L.: The simulation of the diurnal cycle of convective precipitation over land in a global model, Q. J. Roy. Meteorol. Soc., 130, 3119–3137, 2004. Bechtold, P., Kohler, M., Jung, T., Doblas-Reyes, F., Leutbecher, M., Rodwell, J., Vitart, F., and Balsamo, G.: Advances in simulating atmospheric variability with the ECMWF model: From synoptic to decadal time-scales, Q. J. Roy. Meteorol. Soc., 134, 1337–1351, 2008. Blossey, P. N., Bretherton, C. S., and Cetrone, J.: Cloud-resolving model simulations of KWAJEX: Model sensitivities and comparisons with satellite and radar observations, J. Atmos. Sci., 64, 1488–1508, 2007. Bretherton, C. S.: Challenges in Numerical Modeling of Tropical Circulations. In The Global Circulation of the Atmosphere, edited by: Schneider, T. and Sobel, A. H., Princeton University Press, USA, 302–330, 2007. Bretherton, C. S. and Park, S.: A new moist turbulence parameterization in the Community Atmosphere Model, J. Climate, 22, 3422–3448, 2009. Bretherton, C. S., McCaa, J. R., and Grenier, H.: A new parameterization for shallow cumulus convection and its application to marine subtropical cloud-topped boundary layers. Part I: Description and 1D results, Mon. Weather Rev., 132, 864–882, 2004. Chaboureau, J. P., Guichard, F., Redelsperger, J. L., and Lafore, J. P.: The role of stability and moisture in the diurnal cycle of convection over land, Q. J. Roy. Meteorol. Soc., 130, 3105–3117, 2004. Chikira, M. and Sugizama, M.: A cumulus parameterization with state-dependent entrainment rate, Part I: Description and sensitivity to temperature and humidity profiles, J. Atmos. Sci., 67, 2171–2193, 2010. Collins, W. D., Rasch, P. J., Boville, B. A., Hack, J. J., McCaa, J. R., Williamson, D. L., Briegleb, B. P., Bitz, C. M., Lin, S. J., and Zhang M.: The formulation and atmospheric simulation of the Community Atmosphere Model Version 3 (CAM3), J. Climate, 19, 2144–2161, 2006. Dai, A G., Giorgi, F., and Trenberth, K. E.: Observed and model-simulated diurnal cycles of precipitation over the contiguous United States, J. Geophys. Res., 104, 6377–6402, 1999. Deardorff, J W.: Usefulness of liquid-water potential temperature in a shallow-cloud model, J. Appl. Meteor., 15, 98–102, 1976. Deng, L. P. and Wu, X. Q.: Effects of convective processes on GCM simulations of the Madden-Julian Oscillation, J. Climate, 23, 352–377, 2010. Emanuel, K. A.: A scheme for representing cumulus convection in large-scale models, J. Atmos. Sci., 48, 2313–2335, 1991. Fletcher, J. K. and Bretherton, C. S.: Evaluating boundary layer-based mass flux closures using cloud-resolving model simulations of deep convection, J. Atmos. Sci., 67, 2212–2225, 2010. Grandpeix, J. Y., Lafore, J. P., and Cheruy, F.: A density current parameterization coupled with Emanuel's convection scheme, Part II: 1D simulations, J. Atmos. Sci., 67, 898–922, 2010. Guichard, F, Petch, J. C., Redelsperger, J. L., Bechtold, P., Chaboureau, J. P., Cheinet, S., Grabowski, W., Grenier, H., Jones, C. G., Kohler, M., Piriou, J. M., Tailleux, R., and Tomasini, M.: Modelling the diurnal cycle of deep precipitating convection over land with cloud-resolving models and single-column models, Q. J. Roy. Meteorol. Soc., 130, 3139–3172, 2004. Hack, J. J.: Parameterization of moist convection in the National Center for Atmospheric Research Community Climate Model (CCM2), J. Geophys. Res., 99, 5551–5568, 1994. Hack, J. J. and Pedretti, J. A.: Assessment of solution uncertainties in single-column modeling frameworks, J. Climate, 13, 352–365, 2000. Holtslag, A. A. M. and Boville, B. A.: Local versus nonlocal boundary layer diffusion in a global climate model, J. Climate, 6, 1825–1842, 1993. Kain, J. S.: The Kain-Fritsch convective parameterization: an update, J. Clim. Appl. Meteorol., 43, 170–181, 2004. Khairoutdinov, M. F. and Randall, D. A.: Cloud Resolving Modeling of the ARM Summer 1997 IOP: Model Formulation, Results, Uncertainties, and Sensitivities, J. Atmos. Sci., 60, 607–625, 2003. Khairoutdinov, M. F. and Randall, D. A.: High-resolution simulation of shallow-to-deep convection transition over land, J. Atmos. Sci., 63, 3421–3436, 2006. Kuang, Z. and Bretherton, C. S.: A mass-flux scheme view of a high-resolution simulation of a transition from shallow to deep cumulus convection, J. Atmos. Sci., 63, 1895–1909, 2006. Lee, M I., Schubert, S. D., Suarez, M. J., Held, I. M., Lau, N. C., Ploshay, J. J., Kumar, A., Kim, H. K., and Schemm, J. K. E: An analysis of the warm-season diurnal cycle over the continental United States and northern Mexico in general circulation models, J. Hydrometeorol., 8, 344–366, 2007. Li, L. J., Wang., B., Wang, Y. Q., and Wan, H.: Improvements in climate simulation with modifications to the Tiedtke convective parameterization in the grid-point atmospheric model of IAP LASG (GAMIL), Adv. Atmos. Sci., 24, 323–335, 2007. Lin, J. L.: The double-ITCZ problem in IPCC AR4 coupled GCMs: Ocean-atmosphere feedback analysis, J. Climate, 20, 4497–4525, 2007. Mapes, B.E and Neale, R. B.: Parameterizing convective organization, J. Adv. Model. Earth Syst., 3, M06004, 2011. Neale, R., Richter, J. R., and Jochum, M.: The impact of convection on ENSO: From a delayed oscillator to a series of events, J. Climate, 21, 5904–5924, 2008. Neggers, R. A. J., Siebesma, A. P., and Jonker H. J. J.: A multiparcel model for shallow cumulus convection, J. Atmos. Sci., 1655–1668, 2002. Park, S. and Bretherton, C. S.: The University of Washington shallow convection and moist turbulence schemes and their impact on climate simulations with the Community Atmosphere Model, J. Climate, 22, 3449–3469, 2009. Plant, R. S.: A review of the theoretical basis for bulk mass flux convective parameterization, Atmos. Chem. Phys., 10, 3529–3544, http://dx.doi.org/10.5194/acp-10-3529-2010doi:10.5194/acp-10-3529-2010, 2010. Randall, D. A., Khairoutdinov, M., Arakawa, A., and Grabowski, W.: Breaking the cloud parameterization deadlock, B. Am. Meteorol. Soc., 84, 1547–1564, 2003. Richter, J. R. and Rasch, P. J.: Effects of convective momentum transport on the atmospheric circulation in the Community Atmospheric Model, version 3 (CAM3), J. Climate, 21, 1487–1499, 2008. Rio, C., Hourdin, F., Grandpeix, J. Y., and Lafore, J. P.: Shifting the diurnal cycle of parameterized deep convection over land, Geophys. Res. Lett., 36, L07809, http://dx.doi.org/10.1029/2008GL036779doi:10.1029/2008GL036779, 2009. Siebesma, A. P., Bretherton, C. S., Brown, A., Chlond, A., Cuxart, J., Duynkerke, P. G., Jiang, H., Khairoutdinov, M., Lewellen, D., Moeng, C. H., Sanchez, E., Stevens, B., and Stevens, D. E. : A large-eddy simulation intercomparison study of shallow cumulus convection, J. Atmos. Sci., 60, 1201–1219, 2003. Slingo, J. M., Sperber, K. R., Boyle, J. S., Ceron, J. P., Dix, M., Dugas, B., Ebisuzaki, W., Fyfe, J., Gregory, D., Gueremy, J. F., Hack, J., Harzallah, A., Inness, P., Kitoh, A., Lau, W. K. M., McAvaney, B., Madden, R.,Matthews, A., Palmer, T. N., Park, C. K., Randall, R., and Renno, N.: Intraseasonal oscillations in 15 atmospheric general circulation models: Results from an AMIP diagnostic subproject, Clim. Dynam., 12, 325–257, 1996. Wang, Y. Q., Zhou, L., and Hamilton, K.: Effect of convective entrainment/detrainment on the simulation of the tropical precipitation diurnal cycle, Mon. Weather Rev., 135, 567–585, 2007. Yang, G Y. and Slingo, J.: The diurnal cycle in the Tropics, Mon. Weather Rev., 129, 784–801, 2001. Zhang, B. J. and McFarlane, N. A.: Sensitivity of climate simulations to the parameterization of cumulus convection in the Canadian Climate Centre general circulation model, Atmos.-Ocean, 33, 407–446, 1995. Zhang, G. J. and Mu, M. Q.: Simulation of the Madden-Julian oscillation in the NCAR CCM3 using a revised Zhang-McFarlane convection parameterization scheme, J. Climate, 18, 4046–4064, 2005.