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由于空气负离子存在瞬时性,1 h或2 h的间断性监测很难准确反映其变化趋势。为获得空气负离子的实时变化趋势并准确分析其影响因子,以上海崇明岛5种人工林为研究对象,开展单层结构人工林空气负离子实时监测及主要影响因子的研究。结果表明:人工林空气负离子浓度日变化曲线呈双峰型曲线,但峰值出现的具体时间和大小因优势种不同而有所差异;人工林空气负离子浓度存在季节性差异,不同季节空气负离子浓度的均值大小次序为夏季((1 476±17.1)ions/cm~3)>冬季((1 310±25.2)ions/cm~3)>春季((1 197±12.6)ions/cm~3)>秋季((1 089±12.7)ions/cm~3);5种林分空气负离子浓度的年均值大小次序为池杉林((1 405±16.5)ions/cm~3)>混交林((1 269±18.1)ions/cm~3)>臭椿林((1 259±23.2)ions/cm~3)>水杉林((1 257±210)ions/cm~3)>香樟林((1 093±16.6)ions/cm~3);在一定范围内,林分空气负离子浓度与优势树种树高和环境相对湿度呈正相关,与温度和风速呈负相关;当光照度小于20 000 lx时,林分负离子浓度与光照度呈显著正相关;主成分分析表明,相对湿度和光照度是影响林分空气负离子浓度的主要因素。通过比较优势种光合作用日变化和林分空气负离子浓度日变化相似的“M”形双峰曲线,认为植物光合作用也是影响林分空气负离子浓度的重要因子。
Due to the transient nature of air negative ions, intermittent monitoring at 1 h or 2 h can hardly accurately reflect its changing trend. In order to obtain the real-time trend of air negative ion and to analyze its influencing factors accurately, five kinds of plantations in Chongming Island of Shanghai were selected as research objects to carry out the real-time monitoring of air negative ions in monolayer structure plantation and the main influential factors. The results showed that the diurnal variation curve of air anion concentration in plantation showed a bimodal curve, but the specific time and size of peak appeared different due to the dominant species. There was a seasonal difference in air anion concentration in plantations, and the air anion concentration in different seasons The order of the mean was summer ((1 476 ± 17.1) ions / cm ~ 3)> winter (1 310 ± 25.2) ions / cm ~ 3> ((1 089 ± 12.7) ions / cm ~ 3). The order of average annual air anion concentration of five stands was (1 405 ± 16.5) ions / cm ~ (1 259 ± 23.2) ions / cm ~ 3)> Metasequoia glyptostroboides ((1 257 ± 210) ions / cm ~ 3)> camphorlin (1 093 ± 16.6 ) ions / cm ~ 3). Within a certain range, the air anion concentration in the stand was positively correlated with the tree height and relative humidity of the dominant species and negatively correlated with temperature and wind speed. When the illumination was less than 20 000 lx, the negative ion concentration And the light intensity was significantly and positively correlated. The principal component analysis showed that the relative humidity and light intensity were the main factors affecting the air anion concentration in the stand. By comparing the “M” -shape bimodal curve with the diurnal variation of photosynthesis and the daily diurnal variation of air anion concentration, the photosynthesis of plants is also considered as an important factor affecting the air anion concentration in the stand.