Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 7 5 2007 10.5194/acpd-7-14675-2007 http://www.atmos-chem-phys-discuss.net/7/14675/2007/ http://www.atmos-chem-phys-discuss.net/7/14675/2007/acpd-7-14675-2007.html http://www.atmos-chem-phys-discuss.net/7/14675/2007/acpd-7-14675-2007.pdf 14675 14706 2007-10-15 Introduction of prognostic rain in ECHAM5: design and Single Column Model simulations R. Posselt rebekka.posselt@env.ethz.ch U. Lohmann Institute for Atmospheric and Climate Science, ETH Zurich, Universitaetsstrasse 16, 8092 Zurich, Switzerland Prognostic equations for the rain mass mixing ratio and the rain drop number concentration are introduced into the large-scale cloud microphysics parameterization of the ECHAM5 general circulation model (ECHAM5-RAIN). For this a rain flux from one level to the next with the appropriate fall speed is introduced. This maintains rain water in the atmosphere to be available for the next time step. Rain formation in ECHAM5-RAIN is, therefore, less dependent on the autoconversion rate than the standard ECHAM5 but shifts the emphasis towards the accretion rates in accordance with observations. ECHAM5-RAIN is tested and evaluated with two cases: the continental mid-latitude ARM Cloud IOP (shallow frontal cloud case – March 2000) and EPIC (a marine stratocumulus study – October 2001). The prognostic equations for rain hardly affect the amount and timing of precipitation at the surface in different Single Column Model (SCM) simulations for heavy precipitating clouds because heavy rain depends mainly on the large-scale forcing. In case of thin, drizzling clouds (i.e., stratocumulus), an increase in surface precipitation is caused by more sub-time steps used in the prognostic rain scheme until convergence is reached. Cloud microphysical quantities, such as liquid and rain water, are more sensitive to the number of sub-time steps for light precipitation. This results from the decreasing autoconversion rate and increasing accretion rate. Albrecht, B A.: Aerosols, cloud microphysics, and fractional cloudiness, Science, 245, 1227–1230, 1989. ARM: ARM Cloud IOP, prefixhttp://iop.archive.arm.gov/arm-iop/, access: April 2007, 2000. Bretherton, C S., Uttal, T., Fairall, C W., Yuter, S E., Weller, R A., Baumgardner, D., Comstock, K., Wood, R., and Raga, G B.: The EPIC 2001 stratocumulus study, Bull. Amer. Meteorol. Soc., 85, 967–977, 2004. Denman, K.L., Brasseur, G., Chidthaisong, A., Ciais, P., Cox, P., Dickinson, R., Hauglustaine, D., Heinze, C., Holland, E., Jacob, D., Lohmann, U., Ramachandran, S., da~Silva~Dias, P., Wofsy, S., and Zhang, X.: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, chap. Couplings Between Changes in the Climate System and Biogeochemistry, pp. 499 – 588, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2007. EPIC: EPIC Integrated Dataset, prefixhttp://www.atmos.washington.edu/~caldwep/research/ScDataset/sc_integ_data_fr.htm, access: April 2007, 2005. Feingold, G., Cotton, W R., Kreidenweis, S M., and Davis, J T.: The impact of giant cloud condensation nuclei on drizzle formation in stratocumulus: Implications for cloud radiative properties, J. Atmos. Sci., 56, 4100–4117, 1999. Fowler, L D., Randall, D A., and Rutledge, S A.: Liquid and ice cloud microphysics in the CSU general circulation model. Part I: Model description and simulated microphysical processes, J. Clim., 9, 489–529, 1996. Ghan, S J. and Easter, R C.: Computationally efficient approximations to stratiform cloud microphysics parameterization, Mon. Weather Rev., 120, 1572–1582, 1992. Grabowski, W W.: Toward cloud resolving modeling of large-scale tropical circulations: A simple cloud microphysics parameterization, J. Atmos. Sci., 55, 3283–3298, 1998. Grabowski, W W.: A parameterization of cloud microphysics for long-term cloud-resolving modeling of tropical convection, Atmos. Res., 52, 17–41, 1999. Grabowski, W W. and Smolarkiewicz, P K.: A multiscale anelastic model for meteorological research, Mon. Weather Rev., 130, 939–956, 2002. Hatfield, J L. and Prueger, J H.: Impacts of changing precipitation patterns on water quality, J. Soil Water Conserv., 59, 51–58, 2004. Jensen, M. and Johnson, K.: 3rd ARM Quaterly Report: Continuous Profiles of Cloud Microphysical Properties for the Fixed Atmospheric Radiation Measurement Sites (DOE/SC-ARM/P-0609), Tech. rep., Atmospheric Radiation Measurement (ARM) Program, 2006. Johnson, D B.: The Role of Giant and Ultragiant Aerosol Particles in Warm Rain Initiation, J. Atmos. Sci., 39, 448–460, 1982. Khairoutdinov, M. and Kogan, Y.: A New Cloud Physics Parameterization in a Large-Eddy Simulation Model of Marine Stratocumulus , Mon. Weather Rev., 128, 229 – 243, 2000. Lohmann, U. and Feichter, J.: Global indirect aerosol effects: a review, Atmos. Chem. Phys., 5, 715–737, 2005. Lohmann, U. and Roeckner, E.: Design and performance of a new cloud microphysics scheme developed for the ECHAM general circulation model, Clim. Dyn., 12, 557–572, 1996. Lohmann, U., Feichter, J., Chuang, C C., and Penner, J E.: Prediction of the number of cloud droplets in the ECHAM GCM, J. Geophys. Res., 104, 9169–9198, 1999. Lohmann, U., Stier, P., Hoose, C., Ferrachat, S., Kloster, S., Roeckner, E., and Zhang, J.: Cloud microphysics and aerosol indirect effects in the global climate model ECHAM5-HAM, Atmos. Chem. Phys., 7, 3425–3446, 2007. Lopez, P.: Implementation and validation of a new prognostic large-scale cloud and precipitation scheme for climate and data-assimilation purposes, Quart. J. R. Met. Soc., 128, 229–257, prefixhttp://dx.doi.org/10.1256/00359000260498879, 2002. Marshall, J S. and Palmer, W M.: The distribution of raindrops with size, J. Meteorol., 5, 165–166, 1948. Penner, J E., Quaas, J., Storelvmo, T., Takemura, T., Boucher, O., Guo, H., Kirkevag, A., Kristjansson, J E., and Seland, O.: Model intercomparison of indirect aerosol effects, Atmos. Chem. Phys., 6, 3391–3405, 2006. Pruppacher, H R. and Klett, J D.: Microphysics of Clouds and Precipitation, Kluwer Academic Publishers, 1997. Roeckner, E., Bäuml, G., Bonaventura, L., Brokopf, R., Esch, M., Giorgetta, M., Hagemann, S., Kirchner, I., Kornblueh, L., Manzini, E., Rhodin, A., Schlese, U., Schulzweida, U., and Tompkins: The atmospheric general circulation modell ECHAM5, Part I: Model description, Tech. Rep. 349, Max-Planck-Institute for Meteorology, Hamburg, Germany, 2003. Rogers, R R., Baumgardner, D., Ethier, S A., Carter, D A., and Ecklund, W L.: Comparison of raindrop size distributions measured by radar wind profiler and by airplane, J. Appl. Meteorol., 32, 694–699, 1993. Rosenfeld, D., Lahav, R., Khain, A., and Pinsky, M.: The role of sea spray in cleansing air pollution over ocean via cloud processes, Science, 297, 1667–1670, 2002. Rotstayn, L D.: A physically based scheme for the treatment of stratiform clouds and precipitation in large-scale models .1. Description and evaluation of the microphysical processes, Q. J. R. Meteorol. Soc., 123, 1227–1282, 1997. Smolarkiewicz, P K. and Margolin, L G.: On forward-in-time differencing for fluids: An Eulerian/semi-Lagrangian nonhydrostatic model for stratified flows, Atmos-Ocean Special, 35, 127–157, 1997. Smolarkiewicz, P K. and Margolin, L G.: MPDATA: A finite-difference solver for geophysical flows, J. Comput. Phys., 140, 459–480, 1998. Srivastava, R C.: Parameterization of raindrop size distributions, J. Atmos. Sci., 35, 108–117, 1978. Stier, P., Feichter, J., Kinne, S., Kloster, S., Vignati, E., Wilson, J., Ganzeveld, L., Tegen, I., Werner, M., Balkanski, Y., Schulz, M., and Boucher, O.: The aerosol-climate model ECHAM5-HAM, Atmos. Chem. Phys., 5, 1125–1156, 2005. Storelvmo, T., Kristjansson, J E., Myhre, G., Johnsrud, M., and Stordal, F.: Combined observational and modeling based study of the aerosol indirect effect, Atmos. Chem. Phys., 6, 3583–3601, 2006. Tompkins, A M.: A prognostic parameterization for the subgrid-scale variability of water vapor and clouds in large-scale models and its use to diagnose cloud cover, J. Atmos. Sci., 59, 1917–1942, 2002. Twomey, S.: Pollution and planetary albedo, Atmos. Environ., 8, 1251–1256, 1974. Wood, R.: Drizzle in stratiform boundary layer clouds. Part II: Microphysical aspects, J. Atmos. Sci., 62, 3034–3050, 2005. Xu, K M., Zhang, M H., Eitzen, M A., Ghan, S J., Klein, S A., Wu, X Q., Xie, S C., Branson, M., Genio, A. D D., Iacobellis, S F., Khairoutdinov, M., Lin, W Y., Lohmann, U., Randall, D A., Somerville, R. C J., Sud, Y C., Walker, G K., Wolf, A., Yio, J J., and Zhang, J H.: Modeling springtime shallow frontal clouds with cloud-resolving and single-column models, J. Geophys. Res.-Atmos., 110, D15S04, 2005. Yanai, M., Esbensen, S., and Chu, J H.: Determination of bulk properties of tropical cloud clusters from large-scale heat and moisture budgets, J. Atmos. Sci., 30, 611–627, 1973.