Observational and modeling studies of urban atmospheric boundary-layer height and its evolution mechanisms

With a new retrieval method, the mixed layer height (MLH) over the urban area of Beijing is studied using data observed by an eye-safe, compact micro pulse lidar (MPL). The retrieval results show that the retrieved MLH agrees well with that from radiosonde data. The MLH and its growth rate are estimated from the MPL measurements. Entrainment zone thickness (EZT) is extracted from MPL datasets. Entrainment ratio calculated from MLH and EZT is about 0.24. Regional surface sensible heat fluxes are retrieved with a common thermodynamic model. The contribution of mechanical production on MLH evolution is also studied. These results determined from lidar remote sense are useful for modeling air pollution diffusion and transportation.