中文关键词氮湿沉降铵态氮硝态氮雪玉洞流域来源分析 英文关键词nitrogen wet depositionNH₄⁺-NNO₃^--NXueyu Cave watershedsource analysis

作者	单位	E-mail
段世辉	西南大学地理科学学院, 岩溶环境重庆市重点实验室, 重庆 400715	1789935451@qq.com
蒋勇军	西南大学地理科学学院, 岩溶环境重庆市重点实验室, 重庆 400715	jiangjyj@swu.edu.cn
张远瞩	西南大学地理科学学院, 岩溶环境重庆市重点实验室, 重庆 400715
胡刘婵	西南大学地理科学学院, 岩溶环境重庆市重点实验室, 重庆 400715
曾泽	西南大学地理科学学院, 岩溶环境重庆市重点实验室, 重庆 400715
吕现福	西南大学地理科学学院, 岩溶环境重庆市重点实验室, 重庆 400715

中文摘要 以重庆市远郊的丰都雪玉洞流域为研究对象，利用气象站和大气氮沉降仪获取2015年7月~2017年12月的大气降水、NH₄⁺-N和NO₃^--N等数据，通过NH₄⁺-N/NO₃^--N比以及气团后向轨迹模拟探讨了流域大气无机氮湿沉降来源.结果表明：①在观测期内，流域DIN总沉降通量为21.37×10³ kg·a^-1，单位面积沉降通量为14.25 kg·（hm²·a）^-1，其中NH₄⁺-N和NO₃^--N分别为7.72 kg·（hm²·a）^-1和6.53 kg·（hm²·a）^-1，分别占DIN湿沉降量的54%和46%；②DIN湿沉降通量和浓度表现出明显的季节变化，春夏季DIN湿沉降量比秋冬季节高50%，而秋冬季湿沉降的DIN浓度比春夏季高30%；③NH₄⁺-N/NO₃^--N介于0.29~2.27之间，雨季（4月~9月） NH₄⁺-N/NO₃^--N>1，旱季（10月~次年3月） NH₄⁺-N/NO₃^--N<1，表明流域雨季DIN湿沉降主要来源农业源，旱季主要来源于城市源；④流域雨季主要受东南风的影响，大气湿沉降的NH₄⁺-N来源于当地与流域东南方向的农业源，旱季主要受西南风影响，大气湿沉降的NO₃^--N来源于流域西南方向的重庆市区和涪陵等城市源. 英文摘要 Xueyu Cave watershed is located in Fengdu County in the outskirts of Chongqing, where rainfall events were monitored continuously from July 2015 to December 2017. We explored the variation of mass concentration of atmospheric dissolved inorganic nitrogen (NH₄⁺-N and NO₃^--N), and quantitatively calculated its wet deposition fluxes, then the sources of NH₄⁺-N and NO₃^--N were tracked using the Xueyu cave air mass backward trajectory model. The results showed that:①During the monitoring period, the average annual dissolved inorganic nitrogen (DIN) deposition in the watershed was 14.25 kg·(hm²·a)^-1, of which NH₄⁺-N and NO₃^--N were 7.72 kg·(hm²·a)^-1 and 6.53 kg·(hm²·a)^-1, accounting for 54% and 46% of DIN wet precipitation, respectively, and indicating that NH₄⁺-N is the dominant species, followed by NO₃^--N; ②DIN wet deposition flux and concentration showed marked seasonal changes. The DIN wet deposition flux in spring and summer was 50% higher than that in autumn and winter, while the DIN concentration of wet deposition in autumn and winter was 30% higher than those in spring and summer. ③NH₄⁺-N/NO₃^--N was between 0.29 and 2.27, and NH₄⁺-N/NO₃^--N > 1 during the rainy season (April to October) and NH₄⁺-N/NO₃^--N < 1 during the dry season (November to March), indicating that the main sources of DIN wet deposition results from agricultural activities in the rainy season, and urban contributions in the dry season. ④In the study area, the southeastern winds are dominant in the rainy season but southwestern winds are dominant in the dry season. These determine the sources of DIN wet deposition (agricultural or urban).

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