Radiative Properties of Non-spherical Black Carbon Aerosols

Black carbon (BC), as the main absorbing aerosol in the atmosphere, has significant impacts on climate forcing. In recent years, the BC radiative effects have gained increasing interest in remote sensing and climate modeling. However, the radiative properties of BC are significantly affected by the complex morphologies. While a spherical structure is commonly assumed in current climate models and remote sensing techniques, it can introduce substantial errors compared to the laboratory measurements and modeling results from more morphologically realistic models. Thus, the effects of BC non-spherical properties on the radiative properties should be carefully considered. This chapter summarizes the main progress in the studies on the radiative properties of non-spherical BC. First, we have reviewed the morphological characteristics of BC based on the fractal theory, and commonly used non-spherical BC optical models are summarized. Then we have described the measured/modeled BC radiative properties and the optical measurements constrained by BC morphologies. Furthermore, the methods for the parameterizations of the radiative properties of non-spherical BC are summarized, and the coupling of non-spherical BC optical models and chemical transport models are presented. Finally, the summary and future remarks are provided.