NOx作为化石燃料燃烧的重要产物,在大气和生物地球化学循环中扮演着重要的角色,是重要的酸雨物质,它的最终产物是NO3-.为研究亚洲地区大气中NOx的变化历史,从喜马拉雅山中部达索普冰芯中恢复了1600-1997年期间降水中NO3-的浓度变化.结果表明:工业革命以前,大气降水中NO3-浓度变化较为平缓,在1600-1870年期间年平均NO3-浓度保持在约50μL.m-3;工业革命后,NO3-浓度开始增加,特别是1930年以后,伴随着人类活动排放的NOx持续增加,NO3-平均浓度开始迅速增加,1970年以后NO3-平均浓度达到了115μL.m-3,是工业革命前降水中NO3-浓度的两倍多.表明人类活动排放的NOx已影响到喜马拉雅山高山地带.
As the remnant of burning fossil fuels,NOx plays a key role in atmospheric and biogeochemical cycle. NOx in the atmosphere reacts to NO-3 finally. In order to research the historical variation of NOx in the atmosphere in Asia,in this paper,a nitrate record covering the period 1600-1997 from the Dasuopu Glacier in the Himalayas is analyzed. The result reveals that the Himalayas are sensitive to anthropogenic activity in southern Asia. Before 1870 atmospheric nitrate concentration in the Dasuopu ice core was relatively low and constant,but thereafter the concentration increased. Annually average nitrate concentrations doubled from 49 μL·m-3 in the first half of the 19th century to ~96 μL·m-3 in the period from 1930 to 1997 and reached to a maximum of 115 ppb in the period from 1970 to 1997. From 1600 to 1870 the changing tendency of nitrate concentration was near zero. However,in the period 1871-1997 a tendency of 4.3 μL·m-3 per decade was statistically significant at the 95% confidence level. This increasing rate had doubled to an average of 8.9 μL·m-3 per decade from 1930 to 1997,with an acceleration of 16.4 μL·m-3 per decade from 1970 to 1997. This acceleration in nitrate deposition was paralleled by a growing NOx emission over southern Asia resulted from an increasing energy demand. The snow accumulated annually on the Himalayan ice fields,such as the Dasupou Glacier,provides an excellent recording system that can monitor the current anthropogenic emissions.