Numerical simulations of asian dust-aerosols and regional impact on weather and climate-part II: PRCM-dust model simulation

The Purdue Regional Climate Model (PRCM)-Dust, an on-line coupled regional climate-dust model, has been developed to study the dust life cycle and radiative effect of dust on regional weather and climate in Asia in April 1998. The dust model is built on the PRCM discussed in Part I. The dust module includes the major phases of the mineral dust cycle, such as emission, advection, diffusion, and deposition. Furthermore, the optical properties of the dust aerosols are included in the radiation calculation of the PRCM, so that the feedback of radiative forcing of dust-aerosols can be considered in the PRCM modeling. The PRCM-Dust successfully simulated the uplifted dusts to reached around 500-800 hPa over the source regions and remained at 3-5 km or higher to be transported further eastward. The spatial and temporal distributions of the dust aerosols were consistent with the satellite images, the TOMS Aerosol Index maps, lidar observations, and the surface network reports. The regional climatic impacts due to radiative effect of dust aerosols include warming over the high concentration regions in North Asia and cooling in dust-free South Asia. Since there is no nudging, restart, or other artificial forcing in the PRCM-Dust model, the simulated dust concentrations, size distribution, as well as meteorological and soil environments follow the conservation laws of physics. They are suitable to study the interactions among dusts, soil, and regional weather/climate.