北京夏季O3日变化及通量研究

2002年夏季，以北京325m气象塔为观测平台，进行了大气污染物臭氧(O3)及其前体物氮氧化物(NOx)和气象要素加强期的同步观测，并对观测资料做了详尽分析。结果表明：边界层内存在明显的臭氧浓度垂直差异；低层(120m)O3浓度呈明显的日变化，且昼夜振幅较大；夜间高层(280m)O3的化学消耗较弱，可维持较高的浓度；稳定度(Ri)在低层以中性态居多，振幅较小，而在高层以不稳定态居多，振幅较大。两层O3湍流输送通量都呈单峰变化。白天，在O3前体物和局地光化学反应共同作用下，120m左右处的O3污染最大。

Diurnal Variation and Flux of O3 in Summer Atmospheric Boundary Layer Observed on a Meteorological Tower of 325 m in Beijing

O_3,NOx concentrations and meteorological parameters in the urban atmospheric boundary layer in July 2002 were synchronously measured on a meteorological tower of 325m in Beijing.Analysis results show that the O_3 concentration differs remarkably at different levels,showing a distinct diurnal variation at the low level (120m) and maintaining a higher value at night at the higher level (280m) due to a weaker chemical depletion of O_3.In daytime the ozone pollution is most severe at 120m due to the joint effect of O_3 progemtor and local photochemistry reaction.The stability (Ri) is mostly neutral and the variations of Ri are small at lower levels;and it is frequently unstable,and its variation is large at higher levels.The O_3 fluxes transferred by turbulence show a single-peak change both in the lower and higher levels.