Dataset: Biosphere-atmosphere flux measurements of ammonia at a high temporal resolution across ecosystems, climates, and pollution regimes

This dataset contains more than 40,000 records of high-resolution NH₃ biosphere-atmosphere flux measurements compiled from 15 non-agricultural sites across temperate, sub-mediterranean, and continental climates (1991-2024). Measurements were obtained using micrometeorological techniques, primarily the aerodynamic gradient method (AGM) but also relaxed eddy accumulation (REA), and the state-of-the-art eddy covariance method (EC). The measurements cover a range of land use types including grasslands, heathlands, peatlands, dunelands, coniferous and deciduous forests, croplands and bare soil. All datasets have been quality-controlled, harmonized to consistent variable names and units, following CF-convention, and stored in NetCDF format. Flux uncertainties have been included where possible through error propagation. We also supply recalculated fluxes, using the same integrated stability functions across sites. This dataset has been compiled to support the quantification of ecosystem-specific NH₃ inputs, investigation of environmental drivers behind NH₃ exchange, and the validation, calibration and development of NH₃ surface exchange models. The dataset presented here is intended as a living resource: if you have NH₃ flux measurements you would like to contribute to this database, please contact the corresponding author at [e-mail]. Important: We ask users to properly cite the original publications associated with each site when using the data in their own work, appropriately crediting all contributors involved in collecting and processing the data. The original publications can be found both as a global attribute in the NetCDF file and the metadata statement. File overview: Overview file (README.txt): A plain-text summary listing all sites and files included in the dataset, providing an entry point for navigating the database structure. Site NetCDF file ({site_name}.nc): Contains all measurement data and embedded metadata for a single site, structured according to the CF metadata conventions, including NH₃ fluxes, concentrations, meteorological variables, quality flags and uncertainty estimates. Site metadata statement ({site_name}_metadata.txt): A plain-text summary of the site-level global attributes, variable descriptions and units, as reviewed by the data providers. Example notebook (example.ipynb): A Jupyter Notebook demonstrating how to load and inspect the NetCDF files using the Python packages xarray, netCDF4, matplotlib, pandasand numpy.