How aerosol particles act as nuclei for ice and other crystalline phases like hydrates, and how this can quantitatively be described in models, are among the major open questions in atmospheric cloud and climate research. From an ice-microphysical perspective, atmospheric clouds may be subdivided into the following classes, according to their cloud top temperature or region of occurence:
- warm clouds (above 0°C)
- mixed-phase clouds (0°C to -35°C)
- cirrus clouds (below -35°C)
- polar stratospheric clouds (PSCs)
- noctilucent clouds (NLCs).
Except the warm clouds which involve only the gaseous and liquid water phases, these clouds are influenced by a variety of ice nucleation modes induced by soluble and insoluble aerosol particles of different origin and nature.
AIDA ice nucleation experiments
The ice nucleation properties of aerosol particles have been and are still investigated in research projects using the AIDA facility as a cloud simulation chamber. A major objective of this research is to improve existing and develop new parameterisations for describing ice nucleation in cloud, weather forecast and climate models. This is one of the major challenges for improving qantitative precipitation forecast and future climate change projections.
So far we have addressed the following issues of ice nucleation research:
- Homogeneous freezing of sulphuric acid solution particles (Haag et al., 2003; Möhler et al., 2003)
- Freezing rates of pure water droplets (Benz et al., 2005)
- Ice nucleation of aqueous and crystalline ammonium sulphate particles (Abbatt et al, 2006)
- Ice nucleation of soot aerosol particles with different content / coating of inorganic and organic substances (Möhler et al., 2005a, 2005b; Kärcher et al., 2007)
- Ice nucleation of desert dust from different source regions (Mangold et al., 2005; Field et al., 2006; Möhler et al., 2006; Gallavardin et al., 2008; Cziczo et al., 2009a)
- Effect of coating with secondary organics and sulphuric acid on ice nucleation of minerals (Möhler et al., 2008; Cziczo et al., 2009b)
- Ice nucleation efficiency of bacterial cells (Möhler et al., 2007, 2008)
- Ice nucleation on metal oxide nanoparticles as surrogates for meteoric dust (Saunders et al., 2010)
- Ice nuleation of crystalline and glassy organic particles (Murray et al., 2010)
We acknowledge the contribution of national and international partners to AIDA ice nucleation campaigns.
For further information please contact Dr. Ottmar Möhler
Selected AIDA publications on ice nucleation
Abbatt, J. P. D., S. Benz, D. J. Cziczo, Z. Kanji, U. Lohmann, and O. Möhler (2006), Solid ammonium sulfate aerosols as ice nuclei: A pathway for cirrus cloud formation, Science, 313(5794), 1770-1773.
Benz, S., K. Megahed, O. Möhler, H. Saathoff, R. Wagner, and U. Schurath (2005), T-dependent rate measurements of homogeneous ice nucleation in cloud droplets using a large atmospheric simulation chamber, J. Photochem. Photobiol. A, 176(1-3), 208-217.
Cziczo, D. J., O. Stetzer, A. Worringen, M. Ebert, S. Weinbruch, M. Kamphus, S. J. Gallavardin, J. Curtius, S. Borrmann, K. D. Froyd, S. Mertes, O. Mohler, and U. Lohmann (2009a), Inadvertent climate modification due to anthropogenic lead, Nature Geoscience, 2(5), 333-336.
Cziczo, D. J., K. D. Froyd, S. J. Gallavardin, O. Moehler, S. Benz, H. Saathoff, and D. M. Murphy (2009), Deactivation of ice nuclei due to atmospherically relevant surface coatings, Environmental Research Letters, 4(4), doi:10.1088/1748-9326/1084/1084/044013.
Field, P. R., O. Möhler, P. Connolly, M. Krämer, R. Cotton, A. J. Heymsfield, H. Saathoff, and M. Schnaiter (2006), Some ice nucleation characteristics of Asian and Saharan desert dust, Atmos. Chem. Phys., 6, 2991-3006.
Gallavardin, S. J., K. D. Froyd, U. Lohmann, O. Moehler, D. M. Murphy, and D. J. Cziczo (2008), Single Particle Laser Mass Spectrometry Applied to Differential Ice Nucleation Experiments at the AIDA Chamber, Aerosol Sci. Tech., 42(9), 773-791.
Haag, W., B. Kärcher, S. Schaefers, O. Stetzer, O. Möhler, U. Schurath, M. Krämer, and C. Schiller (2003), Numerical simulations of homogeneous freezing processes in the aerosol chamber AIDA, Atmos. Chem. Phys., 3, 195-210.
Kärcher, B., O. Möhler, P. J. DeMott, S. Pechtl, and F. Yu (2007), Insights into the role of soot aerosols in cirrus cloud formation, Atmos. Chem. Phys., 7(16), 4203-4227.
Mangold, A., R. Wagner, H. Saathoff, U. Schurath, C. Giesemann, V. Ebert, M. Kramer, and O. Möhler (2005), Experimental investigation of ice nucleation by different types of aerosols in the aerosol chamber AIDA: implications to microphysics of cirrus clouds, Meteorol. Z., 14(4), 485-497.
Möhler, O., O. Stetzer, S. Schaefers, C. Linke, M. Schnaiter, R. Tiede, H. Saathoff, M. Krämer, A. Mangold, P. Budz, P. Zink, J. Schreiner, K. Mauersberger, W. Haag, B. Kärcher, and U. Schurath (2003), Experimental investigation of homogeneous freezing of sulphuric acid particles in the aerosol chamber AIDA, Atmos. Chem. Phys., 3, 211-223.
Möhler, O., S. Büttner, C. Linke, M. Schnaiter, H. Saathoff, O. Stetzer, R. Wagner, M. Krämer, A. Mangold, V. Ebert, and U. Schurath (2005a), Effect of sulfuric acid coating on heterogeneous ice nucleation by soot aerosol particles, J. Geophys. Res., 110, D11210, doi:11210.11029/12004JD005169.
Möhler, O., C. Linke, H. Saathoff, M. Schnaiter, R. Wagner, A. Mangold, M. Krämer, and U. Schurath (2005b), Ice nucleation on flame soot aerosol of different organic carbon content, Meteorol. Z., 14(4), 477-484.
Möhler, O., P. R. Field, P. Connolly, S. Benz, H. Saathoff, M. Schnaiter, R. Wagner, R. Cotton, M. Krämer, A. Mangold, and A. J. Heymsfield (2006), Efficiency of the deposition mode ice nucleation on mineral dust particles, Atmos. Chem. Phys., 6, 3007-3021.
Mohler, O., P. J. DeMott, G. Vali, and Z. Levin (2007), Microbiology and atmospheric processes: the role of biological particles in cloud physics, Biogeosci., 4(6), 1059-1071.
Möhler, O., D. G. Georgakopoulos, C. E. Morris, S. Benz, V. Ebert, S. Hunsmann, H. Saathoff, M. Schnaiter, and R. Wagner (2008), Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions, Biogeosci., 5(5), 1425-1435.
Möhler, O., S. Benz, H. Saathoff, M. Schnaiter, R. Wagner, J. Schneider, S. Walter, V. Ebert, and S. Wagner (2008), The effect of organic coating on the heterogeneous ice nucleation efficiency of mineral dust aerosols, Environmental Research Letters, 3(2), doi:10.1088/1748-9326/1083/1082/025007.
Murray, B. J., T. W. Wilson, S. Dobbie, Z. Cui, S. M. R. K. Al-Jumur, O. Möhler, M. Schnaiter, R. Wagner, S. Benz, M. Niemand, H. Saathoff, V. Ebert, S. Wagner, and B. Kärcher (2010), Heterogeneous nucleation of ice particles on glassy aerosols under cirrus conditions, Nature Geoscience, 3, 233-237, DOI: 210.1038/NGEO1817.
Saunders, R. W., O. Möhler, M. Schnaiter, S. Benz, R. Wagner, H. Saathoff, P. J. Connolly, R. Burgess, B. J. Murray, M. Gallagher, R. Wills, and J. M. C. Plane (2010), An aerosol chamber investigation of the heterogeneous ice nucleating potential of refractory nanoparticles, Atmos. Chem. Phys., 10, 1227-1247.