[This dataset is embargoed until January 4, 2027]. Measurements were conducted at a long-term environmental monitoring site at Easter Bush Farm in Midlothian, central Scotland. The aerodynamic gradient (AG) flux method was used to measure gas fluxes of H2, and also of CO2. A mast with four inlet heights (0.55, 0.90, 1.70 and 3.05 m) was positioned within an enclosure between two grazed grassland fields. An eddy covariance (EC) mast was erected also in the enclosure adjacent to the AG mast to provide a reference measurement against which to assess the performance of the AG method. Continuous measurements of soil temperature and soil volumetric water content (VWC) were made throughout the measurement period at 5, 10, 20 and 50 cm depth in the soil using buried CS655 water content reflectometers and CS109 temperature probes (both Campbell Scientific, Utah, USA). Air temperature and relative humidity were measured by a HMP60 Humidity and Temperature Probe (Vaisala, Vantaa, Finland) at a height of 1.85 m. Full details about this dataset can be found at https://doi.org/10.5285/077fecc1-6244-4fd7-9d41-6f98763f5f14
