稻田生态系统O_(3)干沉积特性及其对气孔吸收的贡献

Ozone dry deposition characteristics and its contribution to stomatal absorption in a paddy ecosystem

选择江苏省南京市南京信息工程大学永丰农业气象试验站水稻种植区站点,实时观测气象因子、O_(3)浓度、干沉积通量、沉积速率.基于课题组在本地修正过的水稻气孔导度模型量化O_(3)干沉积通量在气孔与非气孔通道的分配特征.结果表明:整个水稻观测期间,O_(3)干沉积速率与通量在夜间变化平缓,白天变化剧烈,均值分别为0.34cm/s与-0.0049μmol/(m^(2)·s),峰值则分别出现在08:30与12:30.此外,水稻生长季期间平均日累积O_(3)总通量、气孔通量与非气孔通量分别为0.40,0.14,0.26mmol/(m^(2)·d),其累积值分别为27.8,9.8,18.0mmol/m^(2).平均O_(3)气孔通量和非气孔通量所占总O_(3)通量的比例分别为34.0%和66.0%,其中白天的比例分别为49.0%与51.0%.

This study selected the main rice planting area in Yongfeng Agro-meteorological Experimental Station of Nanjing University of Information Science and Technology,Nanjing City,Jiangsu Province to carry out continuous observations of meteorological factors,ozone concentration,dry deposition flux,and deposition rate.Based on the modified rice stomatal conductance model,the distribution characteristics of O_(3) dry deposition flux in stomata and non-stomata channels were quantified.During the observation period of rice,the rate and flux of O_(3) dry deposition displayed a relatively gentle change during the nighttime and a more intense change during the daytime,and their average values were 0.34cm/s and-0.0049μmol/(m^(2)·s),respectively,and their peaks appeared at 08:30 and 12:30,respectively,In addition,the daily accumulated O_(3) flux,stomatal flux and non-stomatal flux during the observation period of rice were 0.40,0.14,and 0.26mmol/(m^(2)·d),respectively,and their cumulative values were 27.8,9.8,and 18.0mmol/m^(2),respectively.During the growing season of rice,the ratios of average stomatal O_(3) flux and non-stomatal O_(3) flux to total O_(3) flux were 34.0%and 66.0%,respectively,and the ratios during the daytime were 49.0%and 51.0%,respectively.