Use of the Doppler spectral width to improve the estimation of the convective boundary layer height from UHF wind profiler observations

Enhancement of the air refractive index structure parameter C²_n often occurs at the top of the convective boundary layer (CBL), where the absolute values of the vertical gradients of virtual potential temperature and mixing ratio have a peak. This well-known behavior of the C²_n profiles is often used to locate the height of the mixed layer Z, from UHF wind profiler observations. In the present study, Z_i determination with the C²_n-based technique was investigated for a case of clear-air CBL and a case of cloud-topped CBL. In certain circumstances, such as multifold C²_n peaks or poorly defined peaks, these techniques fail to correctly retrieve CBL height. In order to improve Z_i determination, a new method based on the conjoint use of C²_n and Doppler spectral width profiles is proposed and discussed.