基于氮排放数据的中国大陆大气氮素湿沉降量估算

大气氮素湿沉降与氮的排放紧密相关,通过对已知的氮素排放数据与收集的氮素湿沉降实测数据对应分析发现,不同地区氮素的排放与湿沉降之间存在稳定的比值关系。根据这些比值关系,估算了1980—2007年中国大陆氮素湿沉降量,并运用GIS技术进行了大气氮素湿沉降强度和时空分布。结果表明,我国大陆区域氮素湿沉降呈明显的增长趋势,沉降总量由1980年的4.96Tg增长到2007年的11.80 Tg,单位面积通量分别为516 kg N.km-2.a-1和1 128 kg N.km-2.a-1。氮素湿沉降的空间分布不均,东部、东南沿海地区和中部地区沉降量较高,广大西部地区较低。化学氮肥的施用、燃料的使用和禽畜养殖规模扩大是导致氮湿沉降量增加的主要原因。

Estimation of Atmospheric Nitrogen Wet Deposition in China Mainland from Based on N Emission Data

There has been no systematic measurement of N deposition over space and time in China.However,N deposition is directly related to N emission.Therefore N deposition may be estimated from emission data.A dataset of miscellaneous measurements of wet N deposition in China were compiled and the relationship between emission and deposition was analyzed.The results showed that the deposition/emission ra-tio was dependant on region.The relationship was validated by comparing predicted deposition rates to an additional dataset of measured de-position rates that were not used in the derivation of the relationship.According to these relationships,N wet deposition in China mainland from 1980 to 2007 from an emission dataset was estimated.The results showed that total N wet deposition in China increased significantly from 4.96 Tg in 1980 to 11.80 Tg in 2007,and per unit area deposition rate increased from 516 kg N.km-2.a-1 to 1 128 kg N.km-2.a-1,re-spectively.Spatial and temporal changes of wet deposition were analyzed using GIS technique.N wet deposition rate varied greatly with re-gion,with higher values in southern,central and southeast coast China.At provincial scale,Shanghai had the highest N wet deposition flux,but with a lower increasing rate.N wet deposition rate was lower in the vast western region where there was a high increasing rate occurred in the last 27 years.Chemical fertilizer,fuels and intensive animal husbandry were the major factors influencing the amount of N wet deposition.