Roger A. Pielke Sr. (born October 22, 1946) is an American meteorologist with interests in climate variability and climate change, environmental vulnerability, numerical modeling, atmospheric dynamics, land/ocean – atmosphere interactions, and large eddy/turbulent boundary layer modeling. He particularly focuses on mesoscale weather and climate processes but also investigates on the global, regional, and microscale. Pielke is an ISI Highly Cited Researcher.