One-year observation of urban mixed layer characteristics at Tsukuba, Japan using a micro pulse lidar

One-year characteristics of the urban mixed layer is observed by an eye-saf e, compact micro pulse lidar (MPL). Retrieval method of the mixed layer hei ght (MLH) and the encroachment model of the mixed layer growing are present ed. Two case Studies are carried out using summer and late winter data. Com parisons are made between the aerosol optical thickness, the rawinsonde dat a and the model calculation. The development of the mixed layer exhibits te mporal behavior similar to that of the aerosol optical thickness, but with a time difference of about 1-2 h. The growth rate of the MLH agrees well wi th the encroachment model only in the morning, with considerate deviation d uring the daytime because of the wind effect. One-year growth rate and the maximum MLH are estimated from the MPL measurement between May 1999 and May 2000. The results show that the properties of mixed layer are strongly cor related with the seasonal meteorological conditions. This work also demonst rates that an automated, compact lidar system such as a MPL is quite useful for long-term monitoring of the mixed layer. (C) 2001 Elsevier Science Ltd . All rights reserved.