Abstract
We introduce an innovative method to distinguish soil nitrogen oxides
(NOx=NO+NO2) emissions from satellite-based total NOx emissions using
its seasonal characteristics. To evaluate the approach, we compare the
deviation between the tropospheric NO2 concentration observed by
satellite and two atmospheric composition model simulations driven by
the newly estimated soil NOx emissions and the Copernicus Atmosphere
Monitoring Service (CAMS) inventory. The estimated average soil NOx
emissions in Europe are 2.5 kg N ha-1 yr-1 in 2019, and the annual soil
NOx emissions is approximately 2.5 times larger than that of the CAMS
inventory. Our method can easily be extended to other regions at middle
or high latitudes with similar seasonal characteristics of soil
emissions. The soil emissions are subtracted from the total NOx
emissions yielding realistic anthropogenic NOx emissions. We further
show this also yields realistic anthropogenic CO2 emissions using known
CO2/NOx factors from bottom-up inventories.