Abstract
Potential temperature, specific humidity and wind profiles measured by radiosondes under unstable but windy conditions during FIFE in northeastern Kansas were analyzed within the framework of Monin-Obukhov similarity. Around 86% of these profiles were found to have a height range over which the similarity, formulated in terms of the Businger-Dyer functions, is valid and for which the resulting surface fluxes are in good agreement with independent measurements at ground stations. When scaled with the surface roughness z 0 = 1.05 m and the displacement height d 0 = 26.9 m, for the potential temperature this height range was 45 (±31) ⩽ (z − d 0 )/z 0 ⩽ 104 (±54) and the comparison of the profile-derived surface fluxes with the independent measurements gave a correlation coefficient of r = 0.96. For the specific humidity these values are 42 (±29) ⩽ (z − d 0 )/z 0 ⩽ 96 (±38) and r = 0.94. In terms of the height of the bottom of the inversion H i , in the morning hours the upper limit of (z − d 0 ) in the Monin-Obukhov layer is approximately 0.3H i , whereas for a fully developed ABL it is closer to 0.1H i . Probably, as a result of the short sampling times and perhaps also of the small gradients under the windy conditions, the exact height range of validity was difficult to establish from a mere inspection of these profiles.
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Brutsaert, W., Sugita, M. The extent of the unstable Monin-Obukhov layer for temperature and humidity above complex hilly grassland. Boundary-Layer Meteorol 51, 383–400 (1990). https://doi.org/10.1007/BF00119675
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DOI: https://doi.org/10.1007/BF00119675