Fundamental Study on Control of Atmospheric Environment by Vegetation

NO和NO2通量的微气象测量从Oct.to Dec.in 1994年以上的植被和从Jul.to Oct.in 1995年以上的植被和裸露的土壤。试验地点为沟叶结缕草（Zoysia matrella Merr.）修剪到1厘米（平均叶面积指数4.2）和未开垦的裸露土壤，在大坂府立大学。使用梯度法，连同那些CO2和水蒸气的通量测定。用于计算的数据是在表面附近，在2和8厘米的高度处获得的。在实验室内用荧光分析仪测定了遮光聚四氟乙烯袋中空气中NO和NO2的浓度。在许多情况下，草坪和裸地上方的NO通量方向都是向上的。NO2通量的季节变化范围为-0.1 ~0.3 mgN m^<-2>h^<-1>（Jul.to）-0.1 ~0.1 mgN m^<-2>h^<-1>（10月份），草地上方NO2通量的方向基本上是向下的，而裸地上方的方向不确定。在草坪上方，通量和浓度之间呈负相关。NO_2在草坪上的沉积速率从12月的0.4cm·s ~（-1）下降<-1>Jul.to到12月的0.1cm·s ~<-1>（-1），这可能与气孔吸收NO_2的季节性变化有关。

NO and NO2 fluxes were measured micrometeorologically from Oct.to Dec.in 1994 above vegetation and from Jul.to Oct.in 1995 above vegetation and bare soil. The experimental sites were a lawn (Zoysia matrella Merr.) trimmed to 1 cm (average LAI 4,2) and uncultivated bare soil, in Osaka Prefecture University. The fluxes were determined using a gradient method, together with those of CO2 and water vapor. Data for calculation were obtained near the surfaces, at heights of 2 and 8 cm. NO and NO2 concentration of the air sampled in shaded Teflon bags was determined with a chemiluminescent analyzer in a laboratory. The direction of NO flux was upward above both the lawn and bare soil in many cases. The NO flux changed seasonally from -0.1 -0.3 mgN m^<-2>h^<-1> in Jul.to -0.1 -0.1 mgN m^<-2>h^<-1> in Oct. The direction of NO2 flux was almost downward above the lawn, while that above the bare soil was uncertain. Above the lawn, negative correlations between the flux and concentration were recognized. The NO2 deposition velocity on the lawn decreased from about 0.4cm s^<-1> in Jul.to 0.1 cm s^<-1> in Dec. This was probably caused by the seasonal change in NO2 absorption through stomata.