Description:

Significant progress has been made in the understanding of basic physical mechanisms of aerosol–cloud interactions which has resulted in a reduction in the uncertainty in climate forcing. Studying these physical mechanisms requires detailed information on the size, shape, mass, and optical properties of individual aerosol and cloud particles and their bulk properties over a broad range of atmospheric conditions. Over the last few decades, instrumentation and sensing platforms have evolved, providing increasingly more accurate and larger quantities of data about aerosol and cloud particle properties. This session focuses on  (1) the current status of aerosol and cloud in-situ measurement systems, their strengths and weaknesses and their limitations and uncertainties; (2) the outstanding challenges in in-situ measurement systems that need to be overcome to close gaps in understanding of aerosol and cloud processes; (3) recommendations for moving forward through instrument development programs, laboratory and field campaigns, and new technologies.