中文摘要：

随着我国经济的不断发展，人为活动导致的大气氮沉降显著升高，并已影响到偏远地区的生态系统．为了系统评价天山中部巴音布鲁克高寒草原的大气氮沉降现状，2010年5月至2011年12月对研究区域的氮素干、湿沉降进行观测分析．结果表明：研究区气态HNO3、NH3和NO2的年沉降通量分别为1．47、0．68和0．13kgN·hm^-2，颗粒物中铵态氮（NH4＋）和硝态氮（NO3-）的年通量分别为0．23、0．25kgN·hm^-2；降水中NH4＋-N和NO3--N的年沉降通量分别为2．47和1．59kgN·hm^-2．巴音布鲁克高寒草原的大气氮沉降通量为6．82kg N·hm^-2．其中，湿沉降为4．06kgN·hm^-2·a^-1，干沉降为2．76kgN·hm^-2·a^-1．研究区氮沉降具有明显的季节变化特征：干沉降主要集中在春、夏季，占干沉降总量的72．1％；湿沉降主要集中在夏、秋季，占湿沉降总量的78．3％．

英文摘要：

N deposition has increased significantly with economic development and intensive human activities in China and has affected natural ecosystems in remote areas. To evaluate the atmospheric N deposition of the Bayinbuluk alpine grassland of the central Tianshan Mountains, the dry and wet N depositions were monitored from May 2010 to December 2011. Fluxes of HNO3, NH3, NO2, par- tieulate ammonium and nitrate （pNH4＋and pNO3-） averaged at 1.47, 0.68, 0.13, 0.23 and 0.25 kg N· hm^-2 · a^-1, respectively. Wet depositions of NH4＋-N and NO3--N were 2.47 and 1.59 kg N · hm^-2 · a^-1 , respectively. Total atmospheric inorganic N deposition fluxes averaged at 6.82 kg N· hm^-2 · a^-1, and the wet and dry depositions were 4.06 and 2.76 kg N · hm^-2 ·a^-1 , respec- tively. Nitrogen deposition fluxes showed a significant seasonal change, with 72.1% of dry N depo- sition occurring in spring and summer, and 78.3% of wet N deposition concentrating in summer and autumn.