Experimental, observational, and numerical research on intentional and inadvertent weather modification

Since the discovery of the dry ice and silver iodide effects on clouds by Shaefer and Vonnegut in the late 1940s and early 1950s, artificial weather modification operations that deliberately introduce seeding materials into clouds to impact precipitation have been practiced all around the world. Along with the intentional activities, clouds and precipitation have been inadvertently changed by human activities such as industrial air pollution and urbanization. Despite the inherent difficulty in assessing the effect of intentional and inadvertent weather modification, various materials, methods, technologies, and applications of conducting and evaluating weather modification have been developed. During the last several decades, fundamental theories, observational instruments, and especially numerical models have advanced dramatically in the fields of cloud microphysics, dynamics, and cloud-aerosol interactions to a level that the effects of intentional and inadvertent weather modification can be more or less quantitatively assessed. In this special issue on intentional and inadvertent weather modification research, we have invited several papers that use experimental, observational, and numerical techniques to study the effect.