Date: Wednesday, November 27, 2013
Time: 10:00 am
Location: PHYS 401
Study of the Relative Humidity Impact on Atmospheric Aerosols by Phase Function and Polarization Measurements Using the Polarized Imaging Nephelometer PI-Neph
Atmospheric aerosols influence the Earth's radiation budget by scattering and absorbing sunlight radiation. Aerosols also modify the microphysical and radiative properties, as well as the water content and lifetime of clouds. In atmosphere conditions, aerosol particles experience hygroscopic growth due to the relative humidity (RH) influence. Wet aerosols particles are larger than their dry equivalents; therefore, they scatter more light. The quantitative knowledge of the RH effect on aerosols and its influence on the ability to scatter light is of substantial importance when comparing ground-based observations with other optical aerosol measurements techniques such satellite and photometry retrievals as well as for climate forcing calculations. This study focuses on measurements of aerosol optical properties under the effect of RH by performing different experiments where aerosols are humidified. Our next goal is to investigate the effect of water on aerosol phase function and polarized phase function using the UMBC Polarized Imaging Nephelometer (PI-Neph) designed and built by the LACO group. This study will produce the first reports of laboratory generated and ambient aerosol polarization measurements at high levels of RH.