Climate research in the department covers a broad range of topics using both modeling and experimental approaches. Global and regional climate models are used to investigate the effects of aerosols (e.g., mineral dust, wildfire aerosols, pollution aerosols) on clouds and the hydrological cycle (Liu). Moreover, numerical techniques are applied to understand how precipitation efficiency will change in a future climate and what factors (i.e., microphysical and/or dynamical) are responsible (Lebo). Regional climate modeling focused on orographic precipitation and snowpack dynamics is utilized to improve observational areal estimates of precipitation and snowpack and in order to estimate changes to these variables in a changing global climate (Geerts). A global cloud and aerosol dataset is currently being developed to support climate model evaluation and improvement (Wang). Another focus area is the evaluation and improvement of mixed-phase cloud parameterization in climate models (Liu). After carbon dioxide, methane and absorbing aerosol, which are both being observed using state-of-the-art observation platforms, are the two species with the largest positive radiative forcing and understanding their sources is critical to quantifying the anthropogenic influence on climate (Murphy).