Variations of aerosol optical thickness, water vapor and Ångström parameter over the semi-arid zone of TajikistanSabur F. Abdullaev, Vladimir A. Maslov, Bahron I. Nazarov, Nasridin Kh. Minikulov and Abdugani M. DjuraevE3S Web Conf., 99 (2019) 03004DOI: https://doi.org/10.1051/e3sconf/20199903004