Aerosol and Clouds
Effects of spectral dispersion on clouds and precipitation in mesoscale convective systems
Article first published online: 17 MAR 2011
Copyright 2011 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 116, Issue D6, 27 March 2011
How to Cite
2011), Effects of spectral dispersion on clouds and precipitation in mesoscale convective systems, J. Geophys. Res., 116, D06202, doi:10.1029/2010JD014598., and (
- Issue published online: 17 MAR 2011
- Article first published online: 17 MAR 2011
- Manuscript Accepted: 21 JAN 2011
- Manuscript Revised: 7 JAN 2011
- Manuscript Received: 8 JUN 2010
- spectral dispersion
 The effects of spectral dispersion on clouds and precipitation in mesoscale convective systems have been studied by conducting 10 numerical simulations with different values of spectral dispersion (ɛ = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0) in the clean, semipolluted, and polluted backgrounds. The simulation results show that spectral dispersion affects cloud microphysical properties markedly in each aerosol regime. With an increase in spectral dispersion, both the raindrop concentration and the rainwater content increase, while the mean radius of the raindrops diminishes substantially. Moreover, it is found that the effects of spectral dispersion on simulated precipitation differ in these three aerosol backgrounds and relative humidity. In the clean background and at relatively lower humidity, the average accumulated precipitation is reduced significantly with an increase in spectral dispersion. Precipitation varies nonmonotonically in the semipolluted background, increasing with spectral dispersion at smaller values, while decreasing at larger values. In the mean time, precipitation is continuously enhanced with increasing spectral dispersion in the polluted background. Furthermore, sensitivity tests demonstrate that the possible impacts of spectral dispersion on precipitation varies depending on the relative humidity. For instance, at high relative humidity, an increase in spectral dispersion even in a clean atmosphere leads to more precipitation. Our results could shed light on understanding the influences of aerosols on clouds and precipitation, especially the second aerosol indirect effect.