Abstract
Remote sensing of the lower planetary boundary layer in the vicinity of a meteorological tower on many occasions reveals the existence of shear instability (Kelvin-Helmholtz) waves. In general, such waves are found within shallow strata which are marked by strong thermal stability and large vertical wind shear. The independent and concurrent measurements of the vector wind and temperature, made on a 152-m high tower, allow the construction of wind and temperature profiles. From such measurements, the Richardson number profile is constructed as well as the instability regime according to Drazin's criterion. The results show that regions of shear-instability waves as depicted by the remote sensor (an acoustic sounder) agree well with Drazin's instability regime, and that within such regions the Richardson number is indeed ⩽0.25.
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Emmanuel, C.B. Richardson number profiles through shear instability wave regions observed in the lower planetary boundary layer. Boundary-Layer Meteorol 5, 19–27 (1973). https://doi.org/10.1007/BF02188308
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DOI: https://doi.org/10.1007/BF02188308