www.atmos-chem-phys-discuss.net/8/15855/2008/ doi:10.5194/acpd-8-15855-2008 © Author(s) 2008. This work is distributed under the Creative Commons Attribution 3.0 License. Effects of sea surface winds on marine aerosols characteristics and impacts on longwave radiative forcing over the Arabian Sea 1Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum, 695 022, India 2Centre for Atmospheric and Oceanic Science, Indian Institute of Sciences, Bangalore, India Abstract. Collocated measurements of spectral aerosol optical depths (AODs), total and BC mass concentrations, and number size distributions of near surface aerosols, along with sea surface winds, made onboard a scientific cruise over southeastern Arabian Sea, are used to delineate the effects of changes in the wind speed on aerosol properties and its implication on the shortwave and longwave radiative forcing. The results indicated that an increase in the sea-surface wind speed from calm to moderate (<1 to 8 m s−1) values results in a selective increase of the particle concentrations in the size range 0.5 to 5 μm, leading to significant changes in the size distribution, increase in the mass concentration, decrease in the BC mass fraction, a remarkable increase in AODs in the near infrared and a flattening of the AOD spectrum. The consequent increase in the longwave direct radiative forcing almost entirely offsets the corresponding increase in the short wave direct radiative forcing (or even overcompensates) at the top of the atmosphere; while the surface forcing is offset by about 50%. Discussion Paper (PDF, 939 KB) Interactive Discussion (Closed, 6 Comments) Publication in ACP not foreseen Citation: Nair, Vijayakumar S., Suresh Babu, S., Satheesh, S. K., and Krishna Moorthy, K.: Effects of sea surface winds on marine aerosols characteristics and impacts on longwave radiative forcing over the Arabian Sea, Atmos. Chem. Phys. Discuss., 8, 15855-15899, doi:10.5194/acpd-8-15855-2008, 2008. Bibtex EndNote Reference Manager XML |