Incorporating Nitrogen Stable Isotopes into Atmospheric Chemistry Models

Abstract:

Accurately constraining N emissions in space and time has been a challenge for atmospheric scientists. It has been suggested that ¹⁵N isotopes (δ¹⁵N) may be a way of tracking N emission sources across various spatial and temporal scales. However, the complexity of multiple N sources that can quickly change in intensity has made this a difficult problem. ¹⁵N was incorporated into the emission dataset converted from different versions of National Emission Inventories by SMOKE emission model to test how emission sources would impact the δ¹⁵N value of NO_x. The ¹⁵N incorporated emission dataset was used as inputs to run CMAQ, to explore how atmospheric processes would alter the δ¹⁵N of atmospheric NO_x. ¹⁵N was incorporated into CMAQ’s chemical mechanisms RACM and CB, to analyze how tropospheric photochemistry alter the δ¹⁵N of atmospheric NO_x.