This chapter examines energy exchanges from the surface through the troposphere. Latent heat, sensible heat, and momentum fluxes are examined at surface interfaces and over seasonal and diurnal cycles. The mixed layer is compared over the ocean, humid, and dry tropics. Boundary layer clouds are examined in terms of their connection to the sub-cloud layer properties. Comparisons are made between heat and moisture transport under a variety of convective modes. The trade wind inversion, its maintenance, and east-west structure across the tropical oceans are explored.