B11B-0424
Sensitivity of terrestrial N2O emission to atmospheric nitrogen deposition
Monday, 14 December 2015
Poster Hall (Moscone South)
Akihiko Ito1, Kengo Sudo2, Kazuya Nishina1, Kentaro Ishijima3 and Motoko Ito Inatomi4, (1)NIES National Institute of Environmental Studies, Ibaraki, Japan, (2)Nagoya University, Nagoya, Japan, (3)JAMSTEC Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan, (4)Ibaraki University, Mito, Japan
Abstract:
Terrestrial N2O emission is generated from several nitrogen sources including biological fixation, agricultural fertilizer, and atmospheric deposition. There remain large uncertainties how much N2O is produced from atmospheric deposition. This is a crosscutting issue between global warming and atmospheric pollution. In this study, we assessed the sensitivity of global terrestrial N2O emission to atmospheric deposition, using a process-based model VISIT. In the model, N2O emission is estimated separately for nitrification and denitrfication with the NGAS parameterization. The global simulations were conducted from 1901 to 2014 at spatial resolution of 0.5 degree. Atmospheric deposition of ammonium, NOy, and organic nitrogen simulated by the atmospheric chemistry model CHASER from the pre-industrial time to the present was used. Annual total nitrogen deposition was estimated to increase from 27 Tg N in 1901 to 77 Tg N in 2014. The total N2O emission was also estimated to increase in the period, but it was largely attributable to the increased emission from croplands. We need further investigations for the N2O emission from natural soils, which may be nitrogen-limited.
