Numerical Simulation Of Atmospheric Boundary Layer Response To Aerosol Radiative Effect Using Lidar Measurements

Using new lidar data and a comprehensive model system through idealized numerical experiments, it was investigated that the interaction between urban aerosol radiative effect and atmospheric boundary layer (ABL) in the typical winter weather condition of Lanzhou over complex terrain. Based on the previous researches, the WRF v2.1, version 2.1 with multinest of nonhydrostatic numerical model WRF, was coupled with the ABL model, in which the radiative effect of urban aerosol particles is considered. And they constituted the WRF_ABL model system. After verifying the model sufficiently, the paper performed the numerical simulations and theoretical analyses of the smog aerosol radiative effect as well as the ABL response in Lanzhou in winter 2005 by using the data of backscatter lidar CAML? CE370-2. The work improved the WRF_ABL model system, and had a numerical experiment of the lidar data in the WRFABL model system. A valuable explore to investigate the smog aerosol radiative effect and ABL response had been made.First of all, by using the data of NNRP2 and the ABL measurement campaign during December 1989 in Lanzhou city, the verification of WRF v2.1 model system was worked out. It showed that the model could run steadily and the performance of the simulation of meteorological fields was preferable. Secondly, the WRF v2.1 model was coupled with the ABL model through the nesting scheme. The numerical simulation and case analysis of the ABL structure were performed in the winter heating period of Lanzhou. The results showed that, the simulation was substantially reasonable, and the model was able to be used in investigation of the smog aerosol radiative effects in Lanzhou in winter. Finally, employing the established WRF v2.1 model integrated with the ABL model and in consideration of the radiative effect of atmospheric aerosol, a case analysis on the quantitative influence of the aerosol radiative effect on boundary layer structure of Lanzhou in winter 2005 was discussed by using the lidar data. The primary characteristic was that the long wave radiative effect of aerosol led the lower layer (50~600m) cooling with 0.13—0.18℃/h at night. The wind speed decreased between 50~450m level, the value was 0.1m/s. During daytime, there was an obviously heat increasing in ABL due to the aerosol short wave radiative effect with the increment of about 0.65℃/h below 50m, and about 1.2℃/h in 50~600m. The maximum of the temperature increase occurred near 300m, and the value was 1.68°C/h. Influenced by the temperature increase, the horizontal wind field was adjusted correspondingly, and the wind speed increased by 0.025m/s below 100m level and decreased by 0.22m/s in 100~750m level, the maximum of the wind speed decrease occurred near 300m, the value was 0.6m/s.