Cloud screening algorithm for AERONET database
Jinhuan Qiu · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2005
A reasonable cloud screening algorithm is very important to ensure accuracy of aerosol optical thickness determinations from AERONET database. In this paper, a new cloud screening algorithm is developed. The algorithm uses cloud fraction and a so-called scaling height of the tropospheric aerosol, derived from sunphotometer measurements and surface visibility data, to build the screening criterion. The criterion constraints the scaling height varying in some range. In the condition of no cloud day, the variation range is the monthly-mean scaling height plus 3σ (σ: the standard deviation of scaling height). The larger the cloud fraction is, the smaller the range. The new cloud screening algorithm is used to determine aerosol optical thicknesses from AERONET data measured in Beijing during 2001-2002. According to the application results, the reasonableness of the new algorithm is analyzed.