Exploiting kilometer-scale grid spacing for climate simulations over High Mountain Asia

Mountains play a major role in shaping the weather and climate of the world. However, current under- standing of mountain climate and how it will change with further warming of the atmosphere is still very limited. The uncertainty is in large part related to the coarse grid spacing of current climate models (12-50 kilometres in regional and >50 kilometres in global climate models), which are not able to properly represent the complex mountainous orography and related processes. Thus, employing climate models with a kilometer-scale grid spacing provides a promising path. Here, we present simulations using the COSMO (COnsortium for Small-Scale MOdelling) climate model (COSMO-CLM) performed with a horizontal grid spacing of 2.2 km over all of High Mountain Asia. We evaluate model performance based on preliminary results from case study simulations of different precipitation events and year-long simulations, as well as the added value of kilometer-scale grid spacing. Our analysis lays the foundation for future applications of kilometer-scale runs for decadal simulations of both past and future climate, which comprise the ultimate goal of our project.