资源环境科技发展态势分析平台

Monthly, high resolution (∼2 km) ammonia (NH₃) column maps from the Infrared Atmospheric Sounding Interferometer (IASI) were developed across the contiguous United States and adjacent areas. Ammonia hotspots (95^th percentile of the column distribution) were highly localized with a characteristic length scale of 12 km and median area of 152 km². Five seasonality clusters were identified with k‐means++ clustering. The Midwest and eastern United States had a broad, spring maximum of NH₃ (67% of hotspots in this cluster). The western United States, in contrast, showed a narrower mid‐summer peak (32% of hotspots). IASI spatiotemporal clustering was consistent with those from the Ammonia Monitoring Network. CMAQ and GFDL‐AM3 modeled NH₃ columns have some success replicating the seasonal patterns but did not capture the regional differences. The high spatial‐resolution monthly NH₃ maps serve as a constraint for model simulations and as a guide for the placement of future, ground‐based network sites.