EUREC<sup>4</sup>A

Abstract. The science guiding the EUREC4A campaign and its measurements is presented. comprised roughly 5 weeks of in downstream winter trades North Atlantic – eastward southeastward Barbados. Through ability to characterize processes operating across a wide range scales, marked turning point our observationally study factors influencing clouds trades, how they will respond warming, their link other components earth system, such as upper-ocean or life cycle particulate matter. This characterization was made possible by thousands (2500) sondes distributed measure circulations on meso- (200 km) larger (500 400 h flight time four heavily instrumented research aircraft; global-class vessels; an advanced ground-based cloud observatory; scores autonomous observing platforms upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), along air–sea interface; network water stable isotopologue measurements; targeted tasking satellite remote sensing; modeling with new generation weather climate models. In addition providing outline novel composition into unified coordinated campaign, six distinct scientific facets that explored from Brazil Current rings turbulence-induced clustering droplets influence warm-rain formation are presented overview EUREC4A's outreach activities, environmental impact, guidelines for practice. Track data all standardized accessible at https://doi.org/10.25326/165 (Stevens, 2021), film documenting provided video supplement.