Abstract
In this paper, the authors investigated some microphysical and optical properties of continental clean aerosols from OPAC to determine the effect of hygroscopic growth at the spectral range of 0.25 μm to 2.5 μm and eight relative humidities (RHs) (0%, 50%, 70%, 80%, 90%, 95%, 98% and 99%). The microphysical properties extracted were radii, volume mix ratio, number mix ratio and mass mix ratio as a function of RH while the optical properties are scattering and absorption coefficients and asymmetric parameters. Using the microphysical properties, growth factors of the mixtures were determined while using optical properties the enhancement parameters were determined and then parameterized using some models. We observed that the data fitted the models very well. The angstrom coefficients show that the mixture has bimodal type of distribution with the dominance of fine mode particles.
Highlights
Aerosol in the atmosphere is comprised of numerous and diverse components originating from both natural and anthropogenic activities.An important factor affecting the role aerosols play in climate change is their hygroscopicity and is currently modeled in global climate models (GCMs), mostly to better predict the scattering properties and size distribution under varying humidity conditions [1]
The authors investigated some microphysical and optical properties of continental clean aerosols from OPAC to determine the effect of hygroscopic growth at the spectral range of 0.25 μm to 2.5 μm and eight relative humidities (RHs) (0%, 50%, 70%, 80%, 90%, 95%, 98% and 99%)
Growth factors of the mixtures were determined while using optical properties the enhancement parameters were determined and parameterized using some models
Summary
Aerosol in the atmosphere is comprised of numerous and diverse components originating from both natural and anthropogenic activities.An important factor affecting the role aerosols play in climate change is their hygroscopicity and is currently modeled in global climate models (GCMs), mostly to better predict the scattering properties and size distribution under varying humidity conditions [1]. Numerous studies have investigated the relationship between aerosol scattering and relative humidity RH in terms of the hygroscopic growth factor gf(RH) using humidified nephelometers. These have been used for airborne or ground-based determination of the growth factor considering a “dry” RH over the range from 20% - 40% and a ‘‘wet’’ RH up to 90% [2,3,4,5]. Aerosol particles tend to grow at large relative humidity values as a result of their hygroscopicity. Changes in relative humidity modify their size distribution and refractive index and the optical properties of the aerosol, including the scattering coefficient [6,7,8,9]. A strong correlation of spectral aerosol optical thickness with precipitable water, especially for continental air masses, was shown by Rapti [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
