A New Approach for Measuring Aerosols on Cloudy Days
Researchers in the DOE’s Atmospheric Radiation Measurement (ARM) program developed a technique that may dramatically improve the accuracy (up to ten-fold) of aerosol concentration measurements from satellites on partly cloudy days. Clouds reflect almost the same amount of sunlight in the visible spectral range regardless of the wavelength of light. As a result, ratios of sunlight reflectance at different wavelengths can substantially eliminate the contaminating impact of clouds on aerosol measurements. This new technique, which combines measurements of reflected sunlight at several wavelengths, is a potential new research tool to study the complex and important relationship between aerosols and clouds and to estimate their impact on the regional and global climates.
Kassianov, E.I., and M. Ovtchinnikov. 2008. “On reflectance ratios and aerosol optical depth retrieval in the presence of cumulus clouds.” Geophys. Res. Lett., doi:10.1029/2008GL033231.