Assessment of temperature variability over the Central System of the Iberian Peninsula: Multi-resolution model evaluation

Mountain regions are particularly vulnerable to climate change, as warming reduces snow and ice reserves, thus amplifying positive temperature feedbacks. These processes also have consequences for the hydrological cycle and, therefore, having wide-ranging impacts on society by altering ecosystem services and products. This highlights the importance of understanding how climate change affects mountain areas. However, the limited availability of long-term climate records at high elevations, due to adverse weather conditions, makes high-resolution regional climate models essential for studying complex terrain. The CIMAs (Climate Research Iniciative for Iberian Mountain Areas) project is focused on analyzing climate variability and the impact of climate change on the Central System of the Iberian Peninsula. The studied area is the largest mountain range of the peninsula, reaching 2.592 m at its highest point (Almanzor Peak) and includes surrounding areas with lowest altitudes. CIMAs data is gathered from several institutions in Portugal and Spain and distributes over the domain of interest. It was used to asses the accuracy of two regional climate models: the WRF and the HCLIM models at 4 and 1 km horizontal resolution. Both were configured as convection permitting to allow for explicitly simulating convection. In addition, both models were driven by the same boundary conditions provided by the ERA5 reanalysis, which was also used to evaluate the added value of increased resolution by each regional model. Results show how increasing resolution improves the simulation of temperature at high elevations and allow for better understanding of the climatology of temperature in this mountain range. The comparison of the WRF and HCLIM simulations with observations highlights differences, mostly in the reproduction of extremes.