龙凤山大气近地层O3浓度变化及与其它因素的关系

VARIABILITY AND RELATED FACTORS OF THE SURFACE O3 AT LONGFENGSHAN IN NORTHEAST CHINA

中文关键词:  地面臭氧  氧化氮  气象影响  多变量

英文关键词:Surface O₃  Nox  Meteorological affect  Multivariate

中文摘要:

      研究首次在龙凤山区域大气本底站测得的地面O₃浓度及其变化的资料表明,中国东北农村地面大气O₃浓度总体水平不很高,但在少数特殊的天气条件下,时均浓度可超过国家二级标准。O₃浓度存在明显的季节和日变化,其月平均浓度1995年1月最低(27.5ppb),1994年11月最高(43.2ppb)。O₃日变化幅度夏季的晴天最大(28ppb),冬季的阴天最小(8ppb)。气象要素(尤其是风速、气温和相对湿度等)和NO_x与地面O₃浓度有较密切的关系。用多变量分析法探讨了地面O₃各指标随气象因子和NO_x共同变化的规律,并拟合了寒冷和温暖期里与地面O₃日最高浓度、日最低浓度及日变化幅度有关的方程。

英文摘要:

      Surface O₃ was monitored at GAW's Longfengshan Regional Station(127°36'E, 44°44'N, 330.5m a.s. l), located in northeast China, from Aug. 15, 1994 to Jul. 31, 1995. Data show that the O₃ level at the site was generally not high, though relatively high O₃ concent ration (hourly mean>80 ppb) occurred in the first decade of November 1994. Large seasonal variation with the maximum monthly mean concentration (43.2 ppb) in November 1994 and the minimun (27.5 ppb) in January 1995 was observed. Significant diurnal variation always existed during measurement, but the daily O₃ amplitude depended very much on the weather and the season. The average daily amplitude was about 28 ppb on the clear days in the summer and nearly 8 ppb on the overcast days in the winter. The relationships between some of the meteorological parameters and the surface O₃ have been identified. Wind speed and temperature were found to be positively correlated to the surface O₃ level, while the relative humidity negatively. NO_x also had effects on the surface O₃ concent ration, especially in the colder period when the surface NO_x concentration was relatively high. The "gas phase titration" between NO_x and O₃ could significantly decrease the nighttime surface O₃ concentration so that there was good anticorrelation between the nocturnal NO_x and O₃ concent rations. The daily amplitude was mainly related to the water vapor content, the sunlight time and the UV radiation. Empirical functions of the daily maximum, minimun and amplitude of the surface O₃ both in the colder and in the warmer seasons have been obtained using the step-by-step regression. The data calculated based on the functions coincide well with those observed.