HEAT AND WATER-VAPOR FLUXES IN AIR FLOWING SOUTHWARD OVER THE WESTERN NORTH ATLANTIC OCEAN

Abstract

Turbulent transports of sensible heat and water vapor have been measured from an airplane within southerly-flowing air masses over the western North Atlantic Ocean. It is found that the lower levels of these air masses are unstable and warmed by the transport, of heat from the water below, while the higher levels are stable and warmed by diffusion from the subsidence-inversion air aloft. Average values of the upward flux of sensible heat were found to be 2.1 mcal cm⁻² sec⁻¹ in the middle latitudes and 0.1 mcal cm⁻² sec⁻¹ in the tropics. The downward heat flux was 0.3 mcal cm⁻² sec⁻¹ in the region above the potential temperature minimum formed between the warm air aloft and the water-warmed air below. The flux of latent heat of condensation in the form of water vapor was found to be less than the flux of sensible heat from the ocean in the middle latitudes within 300 km of the east coast and about one order of magnitude greater than the sensible flux farther offshore and in the tropics. The observations are discussed in relation to various theories of heat transport and the process by which the atmosphere accumulates heat from the earth's surface.