• 关键词：贵州  酸雨  穿透雨  淋溶  缓冲

• 基金项目：国家重点基础研究发展计划(973)项目(No.2005CB422207);国家自然科学基金项目(No.40671123)

• 宋文龙
• 北京师范大学地理学与遥感科学学院, 遥感科学国家重点实验室, 环境遥感与数字城市北京市重点实验室, 北京 100875

• 杨胜天
• 北京师范大学地理学与遥感科学学院, 遥感科学国家重点实验室, 环境遥感与数字城市北京市重点实验室, 北京 100875

• 温志群
• 北京师范大学地理学与遥感科学学院, 遥感科学国家重点实验室, 环境遥感与数字城市北京市重点实验室, 北京 100875

• 蔡明勇
• 北京师范大学地理学与遥感科学学院, 遥感科学国家重点实验室, 环境遥感与数字城市北京市重点实验室, 北京 100875

• 白晓辉
• 北京师范大学地理学与遥感科学学院, 遥感科学国家重点实验室, 环境遥感与数字城市北京市重点实验室, 北京 100875

• 高芳
• 北京师范大学环境学院, 北京 100875

• 摘要：在贵州龙里地区开展酸雨模拟实验,并进行天然降雨连续监测,采集马尾松、灌丛冠层穿透雨,结果表明:①研究区降雨中主要阳离子浓度依次为NH⁴⁺>Ca²⁺>K⁺>Na⁺>Mg²⁺,降雨pH值大于6.0时,降雨中NH⁴⁺含量降低,Ca²⁺占优势;降雨中主要阴离子浓度依次为SO₄^2->NO₃^->Cl^-;冠层穿透雨与降雨相比,Na⁺、K⁺、Ca²⁺、Mg²⁺、Cl^-、NO₃^-、SO₄^2-和有机酸富集,特别是K⁺、Ca²⁺、SO₄^2-和有机酸富集倍数最大.②森林冠层对酸雨的缓冲作用体现在酸雨中H⁺与树叶组织中的盐基阳离子发生交换反应,淋出K⁺、Mg²⁺、Ca²⁺等阳离子,减少了酸雨中H⁺含量.Na⁺相对惰性,在降雨和穿透雨中的含量变化不大;K⁺、Mg²⁺、Ca²⁺的淋出是冠层缓冲降雨酸度的主要原因,其中K⁺和Ca²⁺作用最突出,其次是Mg²⁺.③贵州典型森林群落植被冠层的缓冲作用随降雨pH值而变化.对pH值接近3.0的强酸性降雨,经过冠层形成的穿透雨pH值大于降雨,典型森林群落植被冠层对酸雨的缓冲作用依次为马尾松林>针阔混交林>灌丛;对4.0<pH<6.0的降雨,马尾松林冠层使降雨更加酸化,典型森林群落植被冠层对酸雨的缓冲作用依次为针阔混交林>灌丛>马尾松林;对pH值大于6.0的非酸性降雨,经过冠层后被酸化,穿透雨pH值小于降雨;穿透雨pH值基本在4.0～6.0范围内.

• Abstract：Based on the simulation experiments of acid rain and continuous monitoring of precipitation and throughfall in the forest canopy layer of coniferous forest and shrubs at Longli in Guizhou province,the results show that: firstly,the concentrations of cations in precipitation in the study area decrease in the order of NH₄⁺,Ca²⁺,Na⁺,K⁺ and Mg²⁺,and Ca²⁺ becomes dominant over NH₄⁺ when the pH of the rain is above 6.0. Of the measured anions,sulfate is the dominant,NO₃^- the next and chloride is the least. In the through fall,Na⁺,K⁺,Ca²⁺,Mg²⁺,Cl^-,NO₃^-,SO₄^2- and organic acid are enriched,and the enrichment factors of K⁺,Ca²⁺,SO₄^2- and organic acids are larger than those of other ions. Secondly,the H⁺ in acid rain exchanges with K⁺、Mg²⁺ and Ca2 in leaf tissue;As a result,the concentration of H⁺ in acid rain decreases due to the buffering of the canopy. Na⁺ is inert and its concentration in throughfall changes little. The leaching of K⁺,Mg²⁺,Ca²⁺ is the main reason for canopy buffering,in which K⁺ and Ca²⁺ dominate. Thirdly,the canopy buffering of typical forest community in the study area is influenced by the pH of precipitation. For strong acid rain with pHclose to 3.0,the pH of the through fall is higher than the precipitation,and the buffering is strongest in the coniferous forest,the mixed forest next,and the shrubs the weakest. For acid rain with pH between 4.0 and 6.0,the coniferous forest acidifies the rain,and the buffering is strongest in mixed forest,the coniferous forest is the weakest. For rain with pHabove 6.0,the canopy also acidifies the rain. The pHof the throughfall remains within the range of 4.0 to 6.0.

• Key words：Guizhou  acid rain  throughfall  leaching  buffering

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