Catalysis of the reaction: NADP+ + (5Z,13E)-(15S)-9-alpha,15-dihydroxy-11-oxoprosta-5,13-dienoate = NADPH + H+ + (5Z,13E)-9-alpha-hydroxy-11,15-dioxoprosta-5,13-dienoate.
NADP-linked 15-hydroxyprostaglandin dehydrogenase