Forward and Inverse Modelling of Atmospheric Nitrous Oxide Using MIROC4-Atmospheric Chemistry-Transport Model

Atmospheric nitrous oxide (N2O) contributes to global warming and stratospheric ozone depletion, so reducing uncertainty in estimates of emissions from different sources is important for climate policy. In this study, we simulate atmospheric N2O using an chemistry-transport model (ACTM), the results are first compared with situ measurements. Five combinations known (a priori) due natural soil, agricultural land, other human activities, sea–air exchange used. The lifetime 127.6 ± 4.0 yr control ACTM simulation (range indicates interannual variability). Regional optimized Bayesian inverse modeling 84 partitions globe at monthly intervals, measurements 42 sites around world covering 1997–2019. best estimated land ocean 12.99 0.22 TgN yr−1 2.74 0.27 yr−1, respectively, 2000–2009, 14.30 0.20 2.91 2010–2019. On regional scales, find that most recent emission estimation, lower Southern Ocean regions, fits better predicted by inversions. Marginally higher (lower) than inventory/model tropical (extratropical) regions validated independent aircraft observations. Global variabilities show a statistically significant correlation El Niño Oscillation (ENSO). Analysis shows increases over America (Temperate North, Central, Tropical), Central Africa, Asia (South, East, Southeast) between 2000s 2010s. Only Europe as whole recorded slight decrease chemical industry. Our inversions suggest revisions seasonal variations three 15 (East Asia, Temperate North America, Africa), region. terrestrial ecosystem (Vegetation Integrative SImulator Trace Gases) can annual total agreement observed growth rate since 1978, but lag-time scales nitrogen fertilizer application may need be revised.