Investigating the surface energy balance closure over mountain areas: results from the INTERFACE project

This contribution presents an overview of the activities and results of the INTERFACE project, which aims to quantify the non-closure of the surface energy balance across various Alpine sites, where processes related to the lack of closure, i.e., advection due to the development of thermally-driven circulations, are expected to be particularly significant. This objective is addressed by combining flux station and unmanned aerial system (UAS) measurements. The UAS provides spatially distributed observations around eddy-covariance sites, which are essential for estimating advection.

The analysis of eddy-covariance data from various sites representing diverse Alpine contexts (e.g., valley floor, slope, and mountain top) and climatic settings (North vs. South of the main Alpine crest) allows a systematic quantification and comparison of the characteristics of the surface energy balance, including the lack of closure. Particular emphasis is placed on the evaluation of the role of thermally-driven circulations in the non-closure of the surface energy balance, utilizing objective criteria to select days with well-developed slope and valley winds.

The INTERFACE project contributes to the TEAMx international research programme, which aims to improve our understanding of exchange processes in the atmosphere over mountains.