Nitrogen and oxygen isotope balance in tropospheric N2O—An improved budget

In steady state the stable isotopic composition of nitrogen and oxygen in tropospheric N2O is balanced by isotopically light N2O emitted from soils and oceans and isotopically heavy N2O as a return flux from the stratosphere. However, no such balance was reached in calculations given by Kim and Craig (1993). Modifications have been made on their calculations based on the most recent reports on annual global emission of N2O. It is considered that the nitrogen and oxygen isotope budget in tropospheric N2O are approximately in balance if isotopic fractionation effects during the production of N2O in soils and furthermore this paper puts forward further evidence for validating the above results.