New elevational transects for elevation-dependent warming detection and analysis in the Pyrenees.

As part of the LIFE-SIP “Pyrenees4clima” project (2024–2032), several tasks have been launched to detect and analyse elevation-dependent warming (EDW) in the Pyrenees. This mountain range, located in southwestern Europe and connecting the Iberian Peninsula with the rest of the continent, reaches over 3,000 m in its central sector (Aneto Peak, 3,404 m) and still hosts several glaciers. Its west–east orientation, the influence of the Atlantic Ocean and the enclosed Mediterranean Sea, and its location between the westerlies and the subtropical anticyclones make it a particularly relevant region for climate change studies.

One key task involves compiling the longest and most robust temperature series across the range to identify trends and assess significant differences by elevation. Preliminary results already reveal a clear signal of accelerated warming at higher altitudes.

A second, more innovative approach is the establishment (began on summer 2025 and expected to be completed during 2026) of two new altitudinal transects to monitor temperature and relative humidity in detail, identify elevation-related patterns, explore links with atmospheric circulation, and quantify the role of factors such as snow cover in EDW. These transects are located in the Catalan (Bonabé Valley) and the Aragonese (Panticosa) Pyrenees . Both follow UHOP (Unified High Elevation Observatories Platform) guidelines and include an ANCHOR-type station for high-quality, multi-variable measurements. Data collection points are spaced vertically by 200–300 m along ridge zones to minimize cold-air pooling, covering elevations from 1,500–1,600 m up to 2,700–3,050 m. Based on previous experience, we use Gemini Tinytag Plus 2 sensors with radiation shields, anchored to trees or rocks depending on site conditions. Special attention has been given to challenges in snow-covered sectors, including sensor burial, frost, avalanches, and cornice collapses. Automated methods for data quality control are also under development.

This presentation aims to share the expertise gained so far and highlight existing uncertainties to ensure the highest possible data quality and continuity for the complex study of EDW in the Pyrenees.