Ammonia measurements from space with the Cross-track Infrared Sounder (CrIS): characteristics and applications

Presented is an overview demonstrating the current capabilities of the Cross-Track Infrared Sounder (CrIS) Fast Physical Retrieval (CFPR) ammonia (NH₃) product for monitoring, air quality forecast model evaluation, dry deposition estimates, and emissions estimates. Updates from the most recent version of the CFPR-NH₃ are provided, which includes accounting for non-detects under cloud-free conditions when the atmospheric ammonia signal falls below the detection limit of the CrIS sensor. CrIS' ability to observe seasonal variations in ammonia concentrations, such as the detection of spring maximum values over agricultural regions from the fertilizing of crops will also be demonstrated. Furthermore, we show the contribution of wildfires, which is especially important in regions where there are little or no agriculture sources, such as in the northern latitudes of North America during summer. Initial comparisons of CrIS NH₃ satellite observations with air quality model simulations show that in most regions there is general agreement on the spatial distribution of the anthropogenic hotspots, while other areas are markedly different. Finally, we show the use of CrIS satellite ammonia observations to estimate annual and seasonal emissions at county levels and compare them with seasonal emissions available from the bottom-up inventories.