 Another important type of climate model is the regional climate model (RCM). Like GCMs and ESMs, RCMs are designed to be comprehensive and to incorporate realistic, theory-based representations of climate system processes. Unlike GCMs and ESMs, however, RCMs represent only a portion of the globe (e.g., a continent or country), which allows them to have a higher spatiotemporal resolution without exceeding available computing power. With this higher resolution, RCMs can explicitly simulate smaller-scale processes, and they also have the potential to reveal spatial variations in conditions—due to complex topography, for instance—that cannot be resolved by GCMs/ESMs. These features make RCMs an attractive tool for studies of regional climate change (e.g., Mearns et al. 2013). A challenge, however, is specifying conditions at the horizontal boundaries of the modelled region in a physically-consistent way; in practice, these boundary conditions often are informed by results from GCM/ESM simulations.