Validation of the CrIS, IASI, AIRS and GOSAT-NH3 products

Ammonia (NH3) is an essential form of reactive nitrogen whose emissions originate primarily from manure and fertilizer. Atmospheric ammonia is a major precursor of anthropogenic aerosols, for example ammonium nitrate, and negatively impacts both human and ecosystem health. While important, the overall budget of ammonia remains highly uncertain, as in-situ measurements of ammonia are still sparse and typically only provide a very coarse spatial-temporal coverage. Satellite ammonia observations provide a tool to study the budget in detail, however NH3 satellite products validation studies are challenging due to the small scale spatiotemporal variability of atmospheric ammonia. Furthermore, the validation studies typically only focus on a single satellite product and/or comparison to in-situ surface concentrations. This limits such studies to more of an evaluation on how well a satellite represents a surface point measurement instead of validating the satellite vertical sounding (e.g. profile and total column) observations. The ground-based Fourier Transform infrared (FTIR)-NH3 product is an excellent dataset that can more directly evaluate the satellite column and profile type products as it shares a similar sounding measurement. Here we present an update to the FTIR-NH3 record, which includes an extension in both the number of sites as well as the observation period of these stations. Furthermore, we present the latest evaluation and intercomparison results for the most current CrIS (1, and 2), IASI(-A, -B and -C), AIRS and GOSAT(1) ammonia products.