He contributed widely to the understanding of climate variability, the effects of volcanic activity on the Earth System, and the role that clouds play for the energetics of atmospheric circulation. Professor Graf has a special interest in the effects of land-use change on the Tibetan Plateau on weather and climate in East Asia. He is now a visiting fellow of the Chinese Academy of Sciences, studying the variability of the Asian monsoon systems, the teleconnections between the tropical Pacific Ocean and the Northern Hemisphere, and the predictability of the El Niño Southern Oscillation system.