As part of the EUREC4A-OA project (H. Bellenger, S. Speich, LMD), which is the French oceanographic component of the larger EUREC4A field experiments, the “flux mast” national instrument was installed on the Reseach Vessel R/V Atalante from Genavir. The flux mast holds instruments that measure atmospheric turbulence and meteorological variables. The collected data are used to estimate the turbulent fluxes of momentum and heat at the air-sea interface. Specifically, the flux mast instruments measure  air pressure, air temperature, humidity, air refraction index, H2O, the three components of the wind vector, and the upward and downward solar and infrared radiation fluxes. The fluxes calculated are the latent and sensible heat fluxes, and the friction velocity.