Aircraft engine soot as ice nuclei in contrail and cirrus formation

Benjamin Demirdjian (1) , Daniel Ferry (1) , Jean Suzanne (1) , Olga B. B Popovicheva (2) , Natalia M. M Persiantseva (2) , E. E Lukhovitskaya (2) , Natalia K. K Shonija (3) , Nina A. Zubareva (3)

1 CRMCN - Centre de recherche de la matière condensée et des nanosciences
2 Institute of Nuclear Physics
3 Department of Chemistry, Moscow State University

Numerous field observations and modeling studies show a significant role of aircraft black carbon emission on contrail and cirrus formation leading to radiative forcing and climate changes [1]. An increased concentration of aircraft-generated soot particles may initiate heterogeneous reactions influencing the chemical composition of the atmosphere. However, the current ability to predict the climate consequences is limited by qualitative estimations because the data about the physico-chemical properties of aircraft engine soot are scarce. The majority of the present information is based on laboratory-made soots which show a surprising variation in their nucleation properties [2, 3]. As a consequence, we have investigated the physico-chemical properties of aircraft engine soot with respect to their ability to act as cloud condensation nuclei (CCN). A comparison with laboratory-generated kerosene soot shows a significant influence of combustion conditions on the morphology, microstructure, chemical composition, surface nature, and hydrophilicity of soot. The composition and structure heterogeneities separate the engine soot particles in two components: a main fraction made out mainly of amorphous carbon with small amount of oxygen and a fraction of impurities containing an appreciable amount of metal and sulfur. The high concentration of soluble sulfates, of inorganics and of organics in the fraction that contains impurities, explains the engine soot hygroscopicity suggesting a CCN activation at the contrail threshold conditions. Laboratory–made kerosene soot is not able to reproduce the hydrophilicity of engine soot but we show that it is a good surrogate for the insoluble black carbon fraction of aircraft soot in the upper troposphere. [1]IPCC Special Report. Aviation and the global atmosphere, edited by J.E. Penner et al., Cambridge, University Press, 1999. [2]Lamel G. and Novakov T., Water nucleation properties of carbon black and diesel soot particles, Atmos. Environ., 29, 813-823,1995. [3]Diehl K., and Mitra S.K., A laboratory study of the effect of a kerosene-burner exhaust on ice nucleation and the evaporation rate of ice crystals, Atmos. Environ., 32, 3145-3151, 1998.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Océan, Atmosphère

Benjamin Demirdjian, Daniel Ferry, Jean Suzanne, Olga B. B Popovicheva, Natalia M. M Persiantseva, et al.. Aircraft engine soot as ice nuclei in contrail and cirrus formation. First European University: Chemical and biological approaches in Environment, Sep 2004, Marseille, France. ⟨hal-03248778⟩