Patra, P. K., E. J. Dlugokencky, J. W. Elkins, G. S. Dutton, Y. Tohjima, M. Sasakawa, A. Ito, R. F. Weiss, M. Manizza, P. B. Krummel, R. G. Prinn, S. O'Doherty, D. Bianchi, C. Nevison, E. Solazzo, H. Lee, S. Joo, E. A. Kort, S. Maity, and M. Takigawa, 2022: Forward and inverse modelling of atmospheric nitrous oxide using MIROC4-atmospheric chemistry-transport model. J. Meteor. Soc. Japan, 100, 361-386.
Graphical Abstract Published
Plain Language Summary: Atmospheric nitrous oxide (N2O) contributes to global warming and stratospheric ozone depletion. Here we aim to better estimate the global and regional N2O emissions from different sources using high-quality atmospheric observations, JAMSTEC’s atmospheric chemistry-transport model (MIROC4-ACTM) and known (a priori) N2O emissions due to natural soil, agricultural land, other human activities and sea-air exchange. Regional N2O emissions are optimised by Bayesian inverse modelling for 84 partitions of the globe at monthly intervals for the period 1997- 2019. Our best estimate global land and ocean emissions are 14.30±0.20 and 2.91±0.27 TgN yr-1, respectively, for 2010-2019 (2010s), corresponding to N2O lifetime of about 127 yr.
- Global land and ocean emission variabilities show significant correlation with El Niño Southern Oscillation (ENSO). Global land emissions increased by 10% in 2010s from 13 TgN yr-1 in 2000s.
- The most recent ocean emission estimation (Fig. 1a), with lower emissions in the Southern Ocean regions, fits better with that predicted by the inversions, i.e., lower increments (Fig. 1d).
- Regional land emissions show increases over much of the America, Central Africa, and Asia regions between the 2000s and 2010s. Only Europe and Japan recorded a slight decrease in N2O emissions.