Observations of vertical humidity distribution above the ocean surface and their relation to evaporation

Abstract

In order to obtain information on the effect of eddy viscosity and eddy diffusion at the boundary between sea and atmosphere, simultaneous measurements of humidity at two, three or four levels between 1 and 38 meters above the sea surface were made from Atlantis during its cruises off the east coast of the United States during the summer of 1935. The 340 series are published in the form of averages for 115 ten-minute intervals. It is now generally accepted that the wind speed in the lowest dekameters of the atmosphere varies as the logarithm of height, provided the lapse rate is not too far from the adiabatic (Lettau, 1939, p. 72 etc.). This is valid within the layer where the normal shearing stress may be considered constant with elevation and equal to the surface resistance. Accordingly the eddy viscosity coeffcient must increase linearly with elevation.