PPAO_NH3_2022_2023

This dataset contains 6-hourly average atmospheric and seawater ammonia (NH₃) measurements from the Penlee Point Atmospheric Observatory (PPAO), United Kingdom from 2022 to 2023. The measurements include air-sea flux estimates of ammonia, alongside supporting meteorological and seawater parameters. The variable list below describes each column, a short description, and associated units. The dataset is provided in CSV format. Column descriptions Date_time - Timestamp of observation (UTC) CH4_dry_ppm - Dry methane mixing ratio (ppm) H2O_mmol - Water vapour mole fraction (mmol/mol) atmospheric_pressure_mbar - Atmospheric pressure (mbar) relative_humidity - Relative humidity (%) air_temperature_degC - Air temperature (°C) windspeed_ms - Wind speed (m s⁻¹) wind_direction_deg - Mean wind direction (°) NH3_ppb - Atmospheric ammonia concentration (ppb) NH4_seawater_uM - Seawater ammonium concentration (µM) seawater_temperature_degC - Seawater temperature (°C) seawater_salinity - Seawater salinity (PSU) seawater_pH - Seawater pH (total scale, unitless) Fd_umol_m2_day - NH₃ air-sea flux (positive = emission) (µmol m⁻² day⁻¹) NH3_seawater_nmol_m3 - Dissolved seawater NH₃ concentration (nmol m⁻³) *** Please note that missing values are are indicative of periods when data did not meet quality control standards, instrument downtime, calibration, and/ experimental tests.