How Similar are Temperature and Humidity Profiles in the Unstable Boundary Layer?

Abstract

A comparison was made between temperature and humidity profiles obtained from radiosonde measurements under unstable conditions over hilly terrain in northeastern Kansas during the summer and fall of 1987. The summer profiles were found to be similar in a layer over the height range given by 65(±45)m≤z;≤124(±54) m where z is the height above the ground surface reference level. Evidence for this similarity was the closeness of the scaled ratio of the temperature and humidity gradients at any given time to the mean Bowen ratio determined at ground-based surface flux stations. Between this layer and the ground surface some similarity was observed in the profiles but it was not manifested as strongly. Above the layer, in the outer region of the atmospheric boundary layer it was found that the profiles of humidity and potential temperature are completely dissimilar in terms of the surface Bowen ratio. The profiles of the fall campaign when soil moisture content was low and vegetation senescent displayed a less pronounced similarity.