Monthly Patterns of Ammonia Over the Contiguous United States at 2‐km Resolution

Abstract

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 (95th 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 midsummer 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.

Ammonia Dry Deposition in an Alpine Ecosystem Traced to Agricultural Emission Hotpots

“…42 Satellite NH 3 measurements show large hotspots over the agricultural regions but relatively lower abundances over the Denver area. 43 Golston et al investigated NH 3 emissions from the CAFOs (dominated by cattle and cows 31 ) and found 50% underestimation by the U.S. National Emission Inventory 2014. 31 In addition, during transport to alpine areas, NH 3 emitted from urban and agricultural regions could be deposited along the path or partitioned into particulate NH 4 + in the aerosol.…”

“…Concentrated animal feeding operations (CAFOs) are the dominant sources of NH 3 emissions from the agricultural areas . Satellite NH 3 measurements show large hotspots over the agricultural regions but relatively lower abundances over the Denver area . Golston et al investigated NH 3 emissions from the CAFOs (dominated by cattle and cows) and found 50% underestimation by the U.S. National Emission Inventory 2014 .…”

The Chesapeake Bay program modeling system: Overview and recommendations for future development

“…To mitigate this uncertainty, model algorithms were developed from field-scale observations (e.g., Bash et al, 2013) but this results in uncertainty for land use types where these detailed measurements are absent. Additionally, ambient atmospheric measurements of nitric acid and ammonia, primary components of nitrogen dry deposition, are uncommon making even a qualitative evaluation difficult (Wang et al, 2021). Improvements in satellite air-quality measurements, specifically NH 3 (Wang et al, 2021), are filling in many of these measurement gaps but do not yet have a sufficient history of observations to assess trends in ambient concentrations.…”

“…Additionally, ambient atmospheric measurements of nitric acid and ammonia, primary components of nitrogen dry deposition, are uncommon making even a qualitative evaluation difficult (Wang et al, 2021). Improvements in satellite air-quality measurements, specifically NH 3 (Wang et al, 2021), are filling in many of these measurement gaps but do not yet have a sufficient history of observations to assess trends in ambient concentrations.…”

4D‐Var Inversion of European NH3 Emissions Using CrIS NH3 Measurements and GEOS‐Chem Adjoint With Bi‐Directional and Uni‐Directional Flux Schemes

“…In terms of spatial coverage and long-term trends, satellite observations of NH 3 offer distinct advantages over surface NH x observations. Space-based observations of NH 3 have thus been leveraged to study and constrain the spatiotemporal variation and magnitude of NH 3 emissions and model simulations of NH x during the past decade (Cao et al, 2020;Chen et al, 2021;Clarisse, Van Damme, Gardner, et al, 2019;Dammers et al, 2019;Evangeliou et al, 2021;Marais et al, 2021;Schiferl et al, 2016;Van Damme et al, 2020;Van Damme et al, 2018;R. Wang et al, 2021;Warner et al, 2016Warner et al, , 2017L.…”