The ACSPO Clear-Sky Mask (ACSM) B. Petrenko 1,2 , A. Ignatov 1 , P. Dash 1,3 , Y. Kihai 1,2 , X. Liang 1,3 1 NOAA/NESDIS/STAR 2 Global Science and Technology, Inc. 3 Cooperative Institute for Research in the Atmosphere OSI SAF SST Retrieval Workshop 5-7 March 2013, Lannion, France