CIMAs: A multi-source climate dataset for high-mountain environments in the Iberian Central System

The Climate research initiative for Iberian Mountain Areas (CIMAs) is a collaborative framework involving several Spanish institutions: the Spanish Meteorological Office (AEMET), Complutense University of Madrid (UCM), Institute of Geosciences (IGEO, CSIC-UCM) and CIEMAT. The main goal of the  initiative is to advance the characterization and understanding of climate variability and change in the Central System of the Iberian Peninsula. Mountain regions are particularly sensitive to climate change, however observational data in these environments remain scarce, heterogeneous and difficult to maintain. CIMAs addresses this challenge by integrating multi-source meteorological datasets from institutions with different measurement protocols, temporal resolutions and data formats, such as AEMET, the Guadarrama Monitoring Network (GuMNet), the Portuguese Meteorological Office (IPMA), hydrological agencies operating Automatic Hydrological Information Systems in Spain (SAIH Duero, SAIH Tajo) and the Portuguese National Water  Resources Information System (SNIRH).
In this work, we present the comprehensive CIMAs framework, which currently articulates three complementary lines of action. First, the development of the observational database, which includes spatial-temporal harmonization, metadata consolidation, systematic quality control, and a version-controlled architecture. Temperature and precipitation databases are currently operational, supplemented by the integration of wind and snow height products.
This robust observational dataset allows for the development and evaluation of regional climate simulations. The initiative employs WRF and HCLIM models to dynamically downscale ERA5 reanalysis up to very high resolutions (1 km) over the 1990-2025 period. These simulations successfully reduce temperature and precipitation biases over mountain areas. Ongoing developments aim to couple these regional models with the global MPI-ESM to simulate future climate scenarios driven by CMIP6 emission pathways up to the year 2300.
Moreover, CIMAs aims to translate this climate research into climate services tailored for end-users. Building upon the integrated observations and simulations, the goal is to develop tools for sustainable territorial planning, vulnerability assessment and sectoral applications such as hydrology, forestry and energy.
The CIMAs framework provides a structured, interoperable basis for integrating climate observations and simulations across high-mountain areas of the Iberian Peninsula. Supported by a dedicated web platform for data visualization and access, it offers a solid foundation for assessing simulation performance, improving regional climate knowledge, and developing actionable climate services.