Summer Land-Atmosphere Coupling over Europe: A Comparative Evaluation of Observation-based Datasets

Land–atmosphere coupling has long been recognized to modulate the surface fluxes partition in transitional evaporative regimes, where soil moisture anomalies control evapotranspiration. However, globally available in-situ observations for these variables remain limited. This study provides, for the first time, a comprehensive assessment of the similarities, dissimilarities, and limitations among observation-based datasets of surface soil moisture, evapotranspiration, potential evapotranspiration, and 2-meter mean air temperature across Europe. The analysis focuses on the IPCC-defined regions of Northern Europe, Eastern Europe, Western-Central Europe, and the Mediterranean during summer (June–August) for the recent 20-year period (2003–2022). In addition, the study evaluates and compares the representation of land–atmosphere coupling across the different datasets. The results show that most datasets exhibit strong agreement across most regions and effectively capture land–atmosphere interactions. The coupling analysis further reveals a clear north–south contrast: Northern Europe is energy-limited, where atmospheric coupling dominates, whereas the Mediterranean is water-limited, with stronger terrestrial coupling. Central and Eastern Europe show more variability within the season and across years. Overall, the findings highlight reasonable consistency among datasets in representing land–atmosphere processes, despite existing uncertainties.

Keywords: surface soil moisture, evapotranspiration, land-atmosphere coupling, summer