关于对流层大气N_2O氮、氧稳定同位素负荷平衡的初步探讨

Improved Estimates for Nitrogen and Oxygen IsotopeBudget Balance of Tropospheric N2O*

对流层大气Ｎ２Ｏ的氮、氧稳定同位素负荷由地表和海洋释放的富轻同位素的Ｎ２Ｏ与平流层回流的富重同位素的Ｎ２Ｏ来平衡，但Ｋｉｍ和Ｃｒａｉｇ的计算方案无法使之平衡［１］．笔者根据全球Ｎ２Ｏ释放源最近的年释放量估算值，对Ｋｉｍ和Ｃｒａｉｇ［１］的计算方案进行了初步改进，在考虑土壤Ｎ２Ｏ生成过程中氮、氧稳定同位素的分馏效应和氧同位素的纬度变化效应后，推论出全球Ｎ２Ｏ释放源最近的年释放量估算值能使对流层大气Ｎ２Ｏ氮、氧稳定同位素负荷分别接近于平衡．

In steady state,the nitrogen and oxygen isotope budgets from the global N2O sources which are uniformly depleted in heavy isotopes and isotopically lighter than the tropospheric N2O are balanced respectively to the returned N2O from stratosphere enriched in the heavy isotopesKim and Craig(1993) failed to make their estimated results balanceThis paper improves Kim and Graigs estimation method based upon global N2O sources and their emissions updatedWhen considering isotopic fractionation effects during N2O producing in soils and the latitude effect for nitrogen and oxygen isotopic ratios of N2O,the results can make nitrogen and oxygen isotopes budget of tropospheric N2O approximately balanceFurthermore,this paper puts forward future studies which can validate above results