Observation of sensible and latent heat flux profiles with lidar

[摘要] We present the first measurement of the sensible heat flux ( H ) profile in the convective boundary layer (CBL) derived from the covariance of collocated vertical-pointing temperature rotational Raman lidar and Doppler wind lidar measurements. The uncertainties of the H measurements due to instrumental noise and limited sampling are also derived and discussed. Simultaneous measurements of the latent heat flux profile ( L ) and other turbulent variables were obtained with the combination of water-vapor differential absorption lidar (WVDIAL) and Doppler lidar. The case study uses a measurement example from the HOPE (HD(CP) 2 Observational Prototype Experiment) campaign, which took place in western Germany in 2013 and presents a cloud-free well-developed quasi-stationary CBL. The mean boundary layer height  z i was at 1230 m above ground level. The results show – as expected – positive values of H in the middle of the CBL. A maximum of ( 182±32 ) W m −2 , with the second number for the noise uncertainty, is found at 0.5  z i . At about 0.7  z i , H changes sign to negative values above. The entrainment flux was ( - 62 ± 27 )  W m −2 . The mean sensible heat flux divergence in the observed part of the CBL above 0.3  z i was −0.28  W m −3 , which corresponds to a warming of 0.83 K h −1 . The L profile shows a slight positive mean flux divergence of 0.12 W m −3 and an entrainment flux of (214±36)  W m −2 . The combination of H and L profiles in combination with variance and other turbulent parameters is very valuable for the evaluation of large-eddy simulation (LES) results and the further improvement and validation of turbulence parameterization schemes.

[学科分类] 内科医学