Compilation of a global inventory of emissions of nitrous oxide

摘要: A global inventory with 1°x1° resolution was compiled of emissions nitrous oxide (N 2 O) to the atmosphere, including from soils under natural vegetation, fertilized agricultural land, grasslands and animal excreta, biomass burning, forest clearing, oceans, fossil fuel biofuel combustion, industrial sources.A simple model production potential N O in vegetation developed analyze relative importance five major controls on production: (i) input organic matter, (ii) soil fertility, (iii) moisture status, (iv) temperature; (v) oxygen status. Indices for were derived gridded (1° x 1° resolution) data bases type texture, normalized difference index (NDVI) climate. The explains close 60% variability found measurements reported at about 30 sites six different ecosystems throughout world. results confirm conclusions earlier studies that source regions are tropics.Literature flux fields show fertilizerinduced emission is higher covering longer periods than which represent short periods. method estimate total annual direct based one year: O-N = I kg ha -1 yr plus 1.25 ± 1% amount fertilizer applied (kg ). This relationship used compile a arable land.The excreta estimates nitrogen (N) excretion by various categories domestic animals. estimated (-100 10 12 g ) suggests associated may be same order magnitude as caused use synthetic (-80 )To illustrate difficulty describe cycling ecosystems, budgets deforestation sequence Atlantic Zone Costa Rica. After clearing an important part mineralized. Part nitrate formed nitrification mineralized lost via leaching, while most loss occurs through denitrification. period 3 5 years easily decomposable material lost, denitrification fluxes decrease time levels lower undisturbed forest. enhanced following tropical accounting this decline along ageing indicates source.Global inventories also fuelwood N2O sources. For oceans literature used. complete all sources, compared inferred inversemodeling. general agreement inverse modeling results. However, there uncertainties, particularly tropics. comparison between modelling, resulted improved understanding some sources:- oceanic previous estimates; 0°N-30°N latitudinal zone Antarctic ocean much mean flux.- Most lands effects fertilizers comes northern hemisphere. Inputs deposition fixation leguminous crops use. Their release similar magnitude.- Fossil-fuel combustion sources dominant 30°N-90°N zone, mainly produced zone.- emitted coastal marine fresh water systems probably stems hemisphere.Global monthly prescribe three-dimensional atmospheric transport model. simulated hemispheric surface concentration ppb southern observations. modeled concentrations over strong continental interiors up those oceans. Predicted hemisphere somewhat summer winter, seasonality emissions. no seasonal variation small more consistent measurements. Inconsistencies predicted observed overestimation does not account consumption temperate N-limited episodic during early spring autumn. These errors possible underestimation winter exaggerate trends.Another reason inconsistencies measured trends remain unobserved, because remote location monitoring stations. In addition, precision adequate resolving trends.The increase related human food production. growing world population will inevitably lead demand. Moreover, increasing portion At present, 40% cereal 25% root tuber fed An reduction could achieved shift-away production, efficient N, advanced fertilization techniques.Solutions reduce include technical options (e.g. development new catalysts) energy saving. Several chemical processes generate O, but so far only nitric adipic acid have been quantified. currently decreasing producers agreed