Air-sea energy and mass exchanges represent the language of ocean-atmosphere communication. Surface energy fluxes force ocean and atmospheric dynamics and provide feedbacks in a coupled climate system. Accurate estimation of surface energy and mass fluxes is critical for the closure of the ocean energy balance. Surface energy fluxes play a crucial role in the multiscale variability of a coupled climate system and remain effective indicators of climate change. This session intends to provide a dialogue between developers and users of surface air-sea flux products. We invite papers dealing with a broad range of surface flux studies, including those focusing on the fundamentals of air-sea flux physics, on the production of air-sea flux estimates, and on application of air-sea flux products in other fields of climate science. Papers dealing with direct flux measurements, remotely sensed fluxes, air-sea fluxes from reanalyses and operational analyses will be welcome, first of all in the context of validation and inter-comparison of different products. We especially welcome studies of space-time variability at all scales - from synoptic and mesoscale to decadal and centennial. We also welcome analyses of model experiments with ocean, atmospheric and climate models driven by surface fluxes.