Workshop Report/Summary

Opportunities to Improve Representation of Clouds and Aerosols in Climate Models with Classified Observing Systems: Proceedings of a Workshop: Abbreviated Version (2016)

The impact of aerosols on the atmosphere is widely acknowledged as one of the most significant and uncertain aspects of climate change projections. Aerosols influence the climate directly by increasing the amount of sunlight reflected back to space and indirectly through their interactions with clouds. Small changes in cloud cover, thickness, altitude, and cloud particle size and type (liquid vs. ice) affect the Earth's radiative balance significantly, but these complex processes are incompletely captured in climate models.

At the request of the Intelligence Community, the National Academies of Sciences, Engineering, and Medicine held a classified workshop in September 2015 that brought together scientists from the civil and intelligence communities to determine the usefulness of classified observing systems to advance understanding of cloud and aerosol interactions. Workshop discussions highlighted several technical, scientific and policy challenges in utilizing the classified data. The most significant challenge, according to several participants, is the difficulty in accessing the data due to their classification. Another major limitation is calibration accuracy, which is critical for data usability for environmental applications. Many workshop participants said that the best path forward is to test the potential utility of the classified data by bringing small groups of civilian scientists with the appropriate clearances together with scientists from the IC to conduct pilot projects. A classified Proceedings of a Workshop was also produced as part of this project.