Title: New Cross-Track Infrared Sounder (CrIS) Satellite Observations of Ammonia
Ammonia (NH3) is essential for agricultural activities and is one of the most important reactive nitrogen species in any ecosystem. It reacts quickly in the atmosphere with acidic species (i.e. nitric acid and sulfuric acid from NOx and SOx) to produce a significant fraction of fine mode particulate matter (PM2.5), which is associated with negative health impacts. Ammonia is also the only PM2.5 precursor that is both currently increasing and projected to continue to increase throughout the next century globally due to increased demand for more and better food (e.g. more livestock production, greater use of fertilizer for crops), especially in developing countries. Despite all this, there are still large uncertainties in our knowledge of the sources and spatiotemporal distributions of ammonia at regional and global scales. However, recent satellite observations are providing a greater understanding of its emission sources, atmospheric transport, and deposition. Presented here are initial results from our recently developed CrIS Fast Physical Retrieval (CFPR) NH3 satellite algorithm with example applications. This retrieval provides boundary-layer concentrations at a spatial resolution of ~12 km with an uncertainty of about 30% twice a day. These results include spatiotemporal maps of ammonia across North America highlighting the emissions from agriculture practices and forest fires (e.g. Fort McMurray fires), initial validations with ground-based observations, model evaluation examples, satellite derived ammonia/methane livestock emission ratio, and the dry deposition flux of nitrogen from ammonia.