Abstract
Measurements of the concentration and size distribution of aerosol particles in the size-ranges of 0.5–20 µm and 16–700 nm diameters were made during six fog episodes over the south Indian Ocean. Observations show that concentrations of particles of all sizes start decreasing 1–2 hours before the occurrence of fog. This decrease is more prominent for coarse particles of >1 µm diameter and continues until 10–20 minutes before the onset of fog when particle concentrations in all size ranges rapidly increase by one/two orders of magnitude in ∼20 minutes. Thereafter, concentrations of particles of all sizes gradually decrease until the dissipation of fog. After the fog dissipation, concentrations of coarse mode particles rapidly increase and restore to their pre-fog levels but concentrations of the Aitken mode particles decrease slowly and reach their pre-fog levels only after 1–2 hours. The net effect of fog is to change the bimodal size distributions of aerosols with a coarse mode at 1.0 µm and an accumulation mode at 40–60 nm to a power law size distribution. It is proposed that the preferential growth and sedimentation of the coarse mode hygroscopic particles in the initial phase cause a large decrease in the aerosol surface area. As a result, the low vapour pressure gases which were initially being used for the growth of coarse mode particles, now accelerate the growth rates of the accumulation and Aitken mode particles.
Similar content being viewed by others
References
Clarke A D, Davis D, Kapustin V N, Eisele F, Chen G, Paluch I, Lenschow D, Bandy A R, Thornton D, Moore K, Mauldin L, Tanner D, Litchy M, Carroll M A, Collins J and Albercook G 1998 Particle nucleation in the tropical boundary layer and its coupling to marine sulfur sources; Science 282 89–92.
Clarke A D, Davis D, Kapustin V N, Eisele F, Chen G, Paluch I, Lenschow D, Bandy A R, Thornton D, Moore K, Mauldin L, Tanner D, Litchy M, Carroll M A, Collins J and Deshpande C G and Kamra A K 2004 The atmospheric electric conductivity and aerosol measurements during fog over the Indian Ocean; Atmos. Res. 70 77–87.
Deshpande C G and Kamra A K 2004 The atmospheric electric conductivity and aerosol measurements during fog over the Indian Ocean; Atmos. Res. 70 77–87.
Dolezalek H 1962 The atmospheric electric fog effect; Rev. Geophys. 1 231–282.
Hoppel WA and Frick G M 1990 Submicron aerosol size distributions measured over the tropical and South Pacific; Atmos. Environ. 24A 645–659.
Kerminen V M, Teinila K and Hillamo R 2000 Chemistry of sea-salt particles in the summer Antarctic atmosphere; Atmos. Environ. 34 2817–2825.
Korhonen P, Kulmala M, Laaksonen A, Viisanen Y, McGraw R and Seinfeld J H 1999 Ternary nucleation of H2SO4, NH3 and H2O in the atmosphere; J. Geophys. Res. 104(D21) 26,349–26,353.
Kulmala M, Pirjola L and Makela J M 2000 Stable sulphate clusters as a source of new atmospheric particles; Nature 404 66–69.
Moore K F, Sherman D E, Reilly J E and Collett Jr J L 2004 Drop size dependent chemical composition in clouds and fogs; Atmos. Environ. 38 1389–1402.
Norman M and Leck C 2005 Distribution of marine boundary layer ammonia over the Atlantic and Indian Oceans during the Aerosols99 cruise; J. Geophys. Res. 110 D16302, doi:10.1029/2005JD005866.
Pant V, Deshpande C G and Kamra A K 2008 On the aerosol number concentration-wind speed relationship during a severe cyclonic storm over south Indian Ocean; J. Geophys. Res. 113 D02206, doi: 10.1029/2006JD008035.
Pant Vimlesh, Deshpande C G and Kamra A K 2009 The concentration and number size distribution measurements of the Marine Boundary Layer aerosols over the Indian Ocean; Atmos. Res. 92 381–393.
Putaud J P, Mihalopoulos N, Nguyen B C, Campin J M and Belviso S 1992 Seasonal variations of atmospheric sulfur dioxide and dimethylsulfide concentrations at Amsterdam Island in the southern Indian Ocean; J. Atmos. Chem. 15 117–131.
Quinn P K, Asher W E and Charlson R J 1992 Equilibria of the marine multiphase ammonia system; J. Atmos. Chem. 14 11–30.
Saiz-Lopez A, Mahajan A S, Salmon R A, Bauguitte S J B, Jones A E, Roscoe H K and Plane J M C 2007 Boundary layer halogens in coastal Antarctica; Science 317 348–351.
Sasakawa M and Uematsu M 2002 Chemical composition of aerosol, sea fog, and rainwater in the marine boundary layer of the northwestern North Pacific and its marginal seas; J. Geophys. Res. 107(D24) 4783, doi:101029/2001JD001004.
Sasakawa M, Ooki A and Uematsu M 2003 Aerosol size distribution during sea fog and its scavenge process of chemical substances over the northwestern North Pacific; J. Geophys. Res. 108(D3) 4120, doi:101029/2002JD002329.
Serbu G P and Trent E M 1958 A study of the use of atmospheric electric measurements in fog forecasting transactions; Amer. Geophys. Union 39 1034–1042.
Ulevicius V, Trakumas S and Girgzdys A 1994 Aerosol size distribution transformation in fog; Atmos. Environ. 28 795–800.
Wang P K, Grover S N and Pruppacher H R 1978 On the effect of electric charges on the scavenging of aerosol particles by cloud and small rain drops; J. Atmos. Sci. 35 1735–1743.
Zhang K M, Knipping E M, Wexler A S, Bhave P V and Tonnesen G S 2006 Reply to comment on “Size distribution of sea-salt emissions as a function of relative humidity”; Atmos. Environ. 40 591–592.
Zhuang L and Huebert B J 1996 Lagrangian analysis of the total ammonia budget during Atlantic Stratocumulus Transition Experiment/Marine Aerosol and Gas Exchange; J. Geophys. Res. 101(D2) 4341–4350.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Pant, V., Deshpande, C.G. & Kamra, A.K. Changes in concentration and size distribution of aerosols during fog over the south Indian Ocean. J Earth Syst Sci 119, 479–487 (2010). https://doi.org/10.1007/s12040-010-0032-7
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12040-010-0032-7