Adventures in Signal Detection with Susan Solomon

Detection of human effects on global climate is a common theme in Professor Susan Solomon’s illustrious scientific career. She is perhaps best known for making the definitive measurements that helped to elucidate the chemical pathways by which chlorofluorocarbons deplete stratospheric ozone. These measurements – and the insights Professor Solomon and her colleagues obtained from them – provided much of the scientific underpinning for the Montreal Protocol. Less well-known by the general public are Professor Solomon’s multi-decadal efforts to identify externally forced signals in many different climate variables. These studies have searched observational climate records not only for the signals of human-caused changes in ozone-depleting substances, well-mixed greenhouse gases, and particulate pollution, but have also identified the natural signatures of large and moderate volcanic eruptions. The spatial scale of Susan Solomon’s signal detection work extends from “Time of Emergence” (ToE) investigations at individual locations on the Earth’s surface to research involving global-scale “fingerprint” patterns. My talk summarizes some of the key scientific findings from Susan’s signal detection work. It also provides a few personal reflections on the rare privilege of collaborating with an extraordinary scientist, educator, and human being.