Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 6 9 2006 10.5194/acp-6-2389-2006 http://www.atmos-chem-phys.net/6/2389/2006/ http://www.atmos-chem-phys.net/6/2389/2006/acp-6-2389-2006.html http://www.atmos-chem-phys.net/6/2389/2006/acp-6-2389-2006.pdf 2389 2399 2006-06-29 Aerosol activation and cloud processing in the global aerosol-climate model ECHAM5-HAM G. J. Roelofs g.j.h.roelofs@phys.uu.nl P. Stier J. Feichter E. Vignati J. Wilson Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University, Utrecht, The Netherlands Max Planck Institute for Meteorology, Hamburg, Germany Institute for the Environment and Sustainability, European Commission Joint Research Centre, Ispra, Italy California Institute of Technology, Pasadena, USA A parameterization for cloud processing is presented that calculates activation of aerosol particles to cloud drops, cloud drop size, and pH-dependent aqueous phase sulfur chemistry. The parameterization is implemented in the global aerosol-climate model ECHAM5-HAM. The cloud processing parameterization uses updraft speed, temperature, and aerosol size and chemical parameters simulated by ECHAM5-HAM to estimate the maximum supersaturation at the cloud base, and subsequently the cloud drop number concentration (CDNC) due to activation. In-cloud sulfate production occurs through oxidation of dissolved SO₂ by ozone and hydrogen peroxide. The model simulates realistic distributions for annually averaged CDNC although it is underestimated especially in remote marine regions. On average, CDNC is dominated by cloud droplets growing on particles from the accumulation mode, with smaller contributions from the Aitken and coarse modes. The simulations indicate that in-cloud sulfate production is a potentially important source of accumulation mode sized cloud condensation nuclei, due to chemical growth of activated Aitken particles and to enhanced coalescence of processed particles. The strength of this source depends on the distribution of produced sulfate over the activated modes. This distribution is affected by uncertainties in many parameters that play a direct role in particle activation, such as the updraft velocity, the aerosol chemical composition and the organic solubility, and the simulated CDNC is found to be relatively sensitive to these uncertainties. Abdul-Razzak, H. and Ghan, S. J.: A parameterization of aerosol activation, 2, Multiple aerosol types, J. Geophys. Res., 105, 6837–6844, doi:10.1029/1999JD901161, 2000. Abdul-Razzak, H. and Ghan, S. J.: A parameterization of aerosol activation, 3, Sectional representation, J. Geophys. Res., 107, 4026, doi:10.1029/2001JD000483, 2002. Albrecht, B. A.: Aerosols, cloud microphysics and fractional cloudiness, Science, 245, 1227–1230, 1989. Bauer, S. E. and Koch, D.: Impact of heterogeneous sulfate formation at mineral dust surfaces on aerosol loads and radiative forcing in the Goddard Institute for Space Studies general circulation model, J. Geophys. Res., 110, D17 202, doi:10.1029/2005JD005870, 2005. Boucher, O. and Lohmann, U.: The sulfate-CCN-cloud albedo effect: A sensitivity study with two general circulation models, Tellus 47B, 281–300, 1995. Easter, R. C., Ghan, S. J., Zhang, Y., Saylor, R. D., Chapman, E. G., Laulainen, N. S., Abdul-Razzak, H., Leung, L. R., Bian, X., and Zaveri, R. A.: MIRAGE: Model description and evaluation of aerosols and trace gases, J. Geophys. Res., 109, D20 210, doi:10.1029/2004JD004571, 2004. Ervens B., Feingold, G., Frost, G. J., and Kreidenweis, S. M.: A modeling study of aqueous production of dicarboxylic acids: 1. Chemical pathways and speciated organic mass production, J. Geophys. Res., 109, D15 205, doi:10.1029/2003JD004387, 2004. Facchini, M. C., Mircea, M., Fuzzi, S., and Charlson, R. J.: Cloud albedo enhancement by surface-active organic solutes in growing droplets, Nature, 401, 257–259, 1999. Feingold, G. and Kreidenweis, S.: Cloud processing of aerosol as modeled by a large eddy simulation with coupled microphysics and aqueous chemistry, J. Geophys. Res, 107, 4687, doi:10.1029/2002JD002054, 2002. Flossmann, A. I.: The scavenging of two different types of marine aerosol particles using a two-dimensional detailed cloud model, Tellus B, 43, 301–321, 1991. Fountoukis, C. and Nenes, A.: Continued development of a cloud droplet formation parameterization for global climate models, J. Geophys. Res., 110, D11 212, doi:10.1029/2004JD005591, 2005. Ghan, S. J., Easter, R. C., Hudson, J., and Breon, F.-M.: Evaluation of aerosol indirect radiative forcing in MIRAGE, J. Geophys. Res., 106, 5317–5334, 2001. Guo, H., Penner, J. E., Herzog, M., and Liu, X.: Comparison of the vertical velocity used to calculate the cloud drop number concentration in a cloud-resolving and a global climate model, Fourteenth ARM Science team Meeting proceedings, Albuquerque, New Mexico, 22–26 March 2004. Han, Q., Rossow, W. B., and Lacis, A. A.: Near-global survey of effective droplet radii in liquid water clouds using ISCCP data, J. Climate, 7, 465–497, 1994. Hagemann S., Arpe, K., and Roeckner, E.: Validation of the hydrological cycle in the ECHAM5 model, J. Climate, in press, 2006. Hänel, G.: The role of aerosol properties during the condensational stage of cloud: a reinvestigation of numerics and microphysics, Beitr. Phys. Atmosph., 60, 321–339, 1987. Hegg, D. A. and Larson, T. V.: The effects of microphysical parameterization on model predictions of sulfate production in clouds, Tellus, B42, 272–284, 1990. Jones, A., Roberts, D., Woodage, M., and Johnson, C.: Indirect sulphate aerosol forcing in a climate model with an interactive sulphur cycle, J. Geophys. Res., 106, 20 293–20 310, 2001. Kreidenweis, S. M., Walcek, C. J., Feingold, G., Gong, W., Jacobson, M. Z., Kim, C., Liu, X., Penner, J. E., Nenes, A., and Seinfeld, J. H.: Modification of aerosol mass and size distribution due to aqueous phase SO$_2$ oxidation in clouds: Comparisons of several models, J. Geophys. Res., 108, 4213, doi:10.1029/2002JD002697, 2003. Kroll, J. H., Nga, L., Murphy, S. M., Flagan, R. C., and Seinfeld, J. H.: Secondary organic aerosol formation from isoprene photooxidation under high-NO$_\rm x$ conditions, Geophys. Res. Lett., 32, L18 808, doi:10.1029/2005GL023637, 2005. Kulmala, M., Laaksonen, A., Korhonen, P., Ahonen, T., and Baret, J.: The effect of atmospheric nitric acid vapor on cloud condensation nucleus activation, J. Geophys. Res., 98, 22 949–22 958, 1993. Lance, S., Nenes, A., and Rissman, T. A.: Chemical and dynamical effects on cloud droplet number: Implications for estimates of the aerosol indirect effect, J. Geophys. Res., 109, D22 208, doi:10.1029/2004JD004596, 2004. Lelieveld, J. and Crutzen, P. J.: Influences of cloud photochemical processes on tropospheric ozone, Nature, 343, 227–233, 1990. Lim, H. J., Carlton, A. G., and Turpin, B. J.: Isoprene forms secondary organic aerosol through cloud processing: model simulations, Environ. Sci. Technol., 39, 4441–4446, 2005. Lohmann, U. and Roeckner, E.: Design and performance of a new cloud microphysics scheme developed for the ECHAM4 general circulation model, Clim. Dyn., 12, 557–572, 1996. Lohmann, U., Feichter, J., Chuang, C. C., and Penner, J. E.: Predicting the number of cloud droplets in the ECHAM GCM, J. Geophys. Res., 104, 9169–9198, 1999. Lohmann, U. and Feichter, J.: Global indirect aerosol effects: a review, Atmos. Chem. Phys., 5, 715–737, 2005. Maria, S. F., Russell, L. M., Gilles, M. K., and Myneni, S. C. B.: Organic aerosol growth mechanisms and their climate-forcing implications, Science, 306, 1921–1924, 2004. Meskhidze, N., Nenes, A., Conant, W. C., and Seinfeld, J. H.: Evaluation of a new cloud droplet activation parameterization with in situ data from CRYSTAL-FACE and CSTRIPE, J. Geophys. Res.,~110, D16 202,~doi:10.1029/2004JD005703, 2005. Nenes, A. and Seinfeld, J. H.: Parameterization of cloud droplet formation in global climate models, J. Geophys. Res., 108, 4415, doi:10.1029/2002JD002911, 2003. O'Dowd, C. D., Facchini, M. C., Cavalli, F., Ceburnis, D., Mircea, M., Decesari, S., Fuzzi, S., Yoon, Y. J., and Putaud, J.-P.: Biogenically-driven organic contribution to marine aerosol, Nature, 431, 676–680, 2004. Pruppacher, H. R. and Klett, J. D.: Microphysics of clouds and precipitation, Kluwer Acad. Dordrecht, The Netherlands, p. 167–190, 1997. Roelofs, G. J.: A cloud chemistry sensitivity study and comparison of explicit and bulk cloud model performance, Atmos. Environ., 27A, 2255–2264, 1993. Roelofs, G. J., Ganzeveld, L. G., and Lelieveld, J.: Simulation of global sulfate distribution and the influence on effective cloud drop radii with a coupled photochemistry-sulfur~cycle model, Tellus 50B, 224–242, 1998. Roelofs, G. J. and Jongen, S.: A model study of the influence of aerosol size and chemical properties on precipitation formation in warm clouds, J. Geophys. Res., 109, D22 201, doi:10.1029/2004JD004779, 2004. Rotstayn, L. D. and Lohmann, U.: Simulation of the tropospheric sulfur cycle in a global model with a physically based cloud scheme, J. Geophys. Res. 107, 4592, doi:10.1029/2002JD002128, 2002. Spracklen, D. V., Pringle, K. J., Carslaw, K. S., Chipperfield, M. P., and Mann, G. W.: A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties, Atmos. Chem. Phys., 5, 2227–2252, 2005. 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. Vignati, E., Wilson, J., and Stier, P.: M7: An efficient size-resolved aerosol microphysics module for large-scale aerosol transport models, J. Geophys. Res., 109, D22 202, doi:10.1029/2003JD004485, 2004. Wild, M. and Roeckner, E.: Radiative fluxes in the ECHAM5 general circulation model, J. Climate, in press, 2006. Wilson, J., Cuvelier, C., and Raes, F.: A modeling study of global mixed aerosol fields, J. Geophys. Res., 106, 34 081–34 108, 2001. Wurzler, S. C., Levin, Z., and Reisin, T. G.: Cloud processing of dust particles and subsequent effects on drop size distributions, J. Aerosol. Sci., 28, 427–428, 1997.