Wu Sun's current work uses atmospheric observations and remotely sensed photosynthetic proxies to constrain space-time patterns of North American carbon fluxes from divergent model estimates. Before joining the Department of Global Ecology at Carnegie, he obtained his B.Sc. in Geology from Nanjing University and Ph.D. in Atmospheric and Oceanic Sciences from UCLA. His research focused on using carbonyl sulfide (COS) measurements to infer photosynthesis. His Ph.D. work combined chamber observations and reactive transport modeling to understand physical and biotic drivers of COS exchange between soils and the atmosphere. His latest work explored applications of COS as a leaf-scale tracer for stomatal conductance.