西宁近郊大气氮干湿沉降研究

发布时间：2017-12-31 08:05

本文关键词：西宁近郊大气氮干湿沉降研究?　出处：《环境科学》2017年04期 　论文类型：期刊论文

【摘要】：本研究在青海省西宁市城郊二十里铺莫家泉湾气象站开展了完整的2年(2014和2015年)大气无机氮干沉降和混合沉降(湿沉降加部分干沉降)监测.干沉降估算通过被动采样器采集的NH_3和NO_2浓度和Geos-Chem全球化学模式模拟的气体干沉降速率相乘获得;混合沉降的测定采用雨量器.结果表明,气态NH_3和NO_2年均浓度分别为8.8μg·m-3和19.6μg·m-3,且2015年NH_3月均浓度显著高于2014年.NH_3浓度的季节变化呈现春夏高、秋冬低的特征,而NO_2浓度季节变化幅度较小.降水中NH_4~+-N和NO-3-N年均浓度为2.2 mg·L~(-1)和1.8 mg·L~(-1),秋季降水NH_4~+-N浓度比其他季节低55%,而NO-3-N浓度在秋冬季比春夏季高约26%.气态NH_3和NO_2的干沉降量分别为9.0 kg·(hm~2·a)~(-1)和2.8 kg·(hm~2·a)~(-1),降水中NH_4~+-N和NO-3-N的混合沉降量分别为7.6 kg·(hm~2·a)~(-1)和6.2 kg·(hm~2·a)~(-1).还原态氮(NH_3和NH_4~+-N)在氮沉降中占主导地位.大气氮素总沉降(干沉降加混合沉降)量为25.6 kg·(hm~2·a)~(-1),为城郊农田提供重要的环境养分;但这一氮素输入量超过了陆地生态系统氮沉降临界负荷[10~20 kg·(hm~2·a)~(-1)],意味着研究区周边林地(如北山)和水体生态系统面临"氮饱和"的环境风险.
[Abstract]:In this study, the atmospheric inorganic nitrogen dry deposition and mixed deposition (wet deposition plus partial dry deposition) were carried out at the Mujiaquan Bay Meteorological Station in Ershipu, Xining City, Qinghai Province, for 2 years (2014 and 2015). Dry deposition estimation is obtained by multiplying the concentrations of NH_3 and NO_2 collected by passive samplers and the dry deposition rates of gases simulated by the Geos-Chem global chemical model. The average annual concentration of gaseous NH_3 and NO_2 are 8.8 渭 g 路m-3 and 19.6 渭 g 路m-3, respectively. The monthly mean concentration of NH_3 in 2015 was significantly higher than that in 2014. The seasonal variation of the concentration of NH3 showed the characteristics of high in spring and summer and low in autumn and winter. The seasonal variation of NO_2 concentration is relatively small. The average annual concentrations of NH4 ~ -N and NO-3-N are 2.2 mg 路L ~ (-1) and 1.8 mg 路L ~ (-1) in precipitation. The NH _ 4 ~ -N concentration in autumn precipitation was 55% lower than that in other seasons. The concentration of NO-3-N in autumn and winter was about 26% higher than that in spring and summer. The dry deposition of gaseous NH_3 and NO_2 were 9.0 kg 路hmc2 路a ~ (-1), respectively. And 2.8 kg 路hm ~ (2 路a) ~ (-1). The mixed precipitation of NH _ 4 ~ -N and NO-3-N in precipitation was 7.6 kg 路hmc2 路a ~ (-1) and 6.2 kg 路hm ~ (2 路a) ~ (-1), respectively. The total atmospheric nitrogen deposition (dry deposition plus mixed deposition) was 25.6 kg 路hmmf2 路a ~ (-1). -1). Providing important environmental nutrients for suburban farmland; But this nitrogen input exceeds the critical load of nitrogen deposition in terrestrial ecosystems. [It means that forest land (such as Beishan) and water ecosystem in the study area face the environmental risk of "nitrogen saturation".
【作者单位】：中国农业大学资源与环境学院;中国科学院生态环境研究中心城市与区域生态国家重点实验室;青海省气象局;北京大学物理学院大气与海洋科学系;中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室;
【基金】：国家自然科学基金项目(41425007)
【分类号】：X51
【正文快照】： 物理研究所大气边界层物理和大气化学国家重点实验室,北京100029)氮(N)是自然界所有有机体生长的一种必需元素,控制着陆地和海洋生态系统的净生产力[1].空气中的氮素主要以三重键结合的氮气(N2)形式存在,约占空气总体积的78%,其不能被生物体直接利用,除非转化成活性氮(Nr,除N2

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