Toward a Global Planetary Boundary Layer Observing System: A Summary

Abstract A global planetary boundary layer (PBL) observing system is urgently needed to address fundamental PBL science questions and societal applications related to climate, weather, and air quality. Such a PBL observing system should optimally combine emerging yet technically viable space-based observations of the PBL thermodynamic structure with complementary surface-based and suborbital assets, while taking advantage of, and helping improve, climate and weather models as well as data assimilation systems. The Earth science community has expressed great interest in improving the characterization of the atmospheric PBL in the recent National Academies of Sciences, Engineering, and Medicine (NASEM) 2017–27 decadal survey for Earth Science and Applications from Space (ESAS). Specifically, higher spatial and temporal resolution observations of PBL temperature and water vapor profiles, and of PBL height, were selected as priorities by the decadal survey, which recommended a PBL mission in its incubation class. In response, NASA established the Decadal Survey Incubation program and a PBL Study Team focused on prioritizing PBL science and technology that would require advancement and development prior to implementation. In this paper, we summarize the key findings of the NASA PBL Study Team report. Significance Statement The planetary boundary layer (PBL) is the atmospheric turbulent layer adjacent to Earth’s surface. Humans live in the PBL, and the weather and climate that we experience have a tremendous impact on our health, safety, and economy. The science community has manifested an urgent need for a global PBL observing system focused on PBL profiles of temperature and water vapor, as well as PBL height, to address fundamental PBL science questions and societal applications. The measurement requirements of such a system will likely not be satisfied using a single measurement technology, and this global PBL observing system should optimally combine a diverse set of space-based observations with suborbital and surface-based measurements.