General information and application procedure for PhD Programmes in Sofia University "St. Kliment Ohridski" can be found
here.
Department of Meteorology and Geophysics is accredited to train PhD students in two programs "Meteorology" and "Physics of Ocean, Atmosphere and Near-Earth Space".
Until recently there was a PhD program in "Geophysics".
PhD Program in "Meteorology"
Synopsis for candidate-doctoral exam for admission in PhD Program "Meteorology" (in Bulgarian).
PhD Program in "Physics of Ocean, Atmosphere and Near-Earth Space"
PhD Program in "Geophysics" - inactive