Simulation Of Dust Aerosol Longwave Radiative Effect And Its Influence On Atmospheric Boundary Layer Using Lidar Measurements

Using new lidar data and a comprehensive model system through numerical experiments, the paper discusses the interaction between dust aerosol longwave radiative effect and atmospheric boundary layer (ABL) in the summer floating dust weather condition of Lanzhou over complex terrain. By employing the WRF-ABL model system including WRF v2.1 which is multinest of nonhydrostatic numerical model, coupled with ABL model, in which the aerosol radiative effect is considered. The paper conducts numerical simulations and analyses of the dust aerosol longwave radiative effect as well as the ABL response in summer of Lanzhou on the basis of the data of backscatter lidar CAML^TM CE-370-2. The floating dust appeared on June 17, 2006. A valuable exploration to investigate the dust aerosol radiative effect and ABL response has been made.First of all, we get the aerosol extinction coefficient retrieved from the CAML^? CE-370-2 backscatter lidar data under the floating dust weather condition from 17 June to 18 June 2006, and analyze the dust aerosol properties. Secondly, simulate the lower layer wind speed and temperature fields in summer over Lanzhou, which are considered as the input background of ABL model, through WRF v2.1 using the NNRP2 data of 2006. Thirdly, put the aerosol extinction coefficient from lidar into the comprehensive WRF-ABL model, and quantify the effect of the dust aerosol longwave radiative effect to the ABL structure. The main simulation results are as follows. At night, the dust aerosols make the lower layer cool, the surface temperature decreases by 0.1K, and the temperature decreases by 0.08～0.1K below 50m. The maximum of cooling rate is 0.11K/h in the layer about 2000～2500m. As to the wind speed of the layer below 1000m, it is bigger under the dust weather condition than the condition where there is no dust. The wind speed increases by 0.002m/s below 50m. The maximum of the wind speed increase occurs about 150～300m with 0.005m/s. After the dust weather lasting about 4 hours, the surface temperature decreases by 0.16K, and the temperature decreases by 0.08～0.23K below 50m. The maximum of the temperature decrease occurs about 2200～2500m with 0.43K. As to the wind speed of the layer below 1000m, it is bigger under the dust weather condition than the condition where there is no dust. The wind speed increases by 0.015～0.042m/s below 50m. The maximum of the wind speed increase occurs about 200～300m with 0.05m/s.