广州近地面臭氧浓度特征及气象影响分析

Guangzhou ground level ozone concentration characteristics and associated meteorological factors

利用2015年广州市近地面逐时臭氧(O_3)观测资料及气象数据,分析了广州地区近地面的O_3浓度时空分布特征及其与气象因子的关系.结果表明:广州地区城郊的O_3浓度高于中心城区;广州地区近地面的O_3浓度超标时间主要出现在4—9月,8月O_3浓度最高,3月O_3浓度最低;O_3浓度日变化呈现"单峰型"分布,早上7:00—8:00出现最低值,15:00达到峰值;O_3浓度与气温呈正相关,当气温高于30℃时,O_3浓度随温度升高增加明显;与相对湿度呈负相关,当相对湿度大于60%时,O_3浓度显著降低;当气压小于1010 hpa时,与气压呈负相关,当气压大于1010 hpa时,与气压呈正相关;当风力为2~3级吹西北偏西至西南偏西风区间时,O_3浓度最高,说明广州偏西部可能存在O_3污染源区;O_3浓度在晴天最高,其次是少云和多云天气,最低是在雨天.总体而言,气温高、日照长、辐射强、气压低、湿度小及2~3级的风力是广州地区近地面产生高浓度O_3的主要气象因素.当广州O_3浓度出现超标时,气温变化范围为25.9~37.4℃,相对湿度变化范围为29%~83%,气压变化范围为989.4~1009.1 h Pa,风速变化范围为0.7~5.8 m·s^(-1),紫外辐射强度日最大1 h均值最小为32.6 W·m^(-2),10:00—14:00均值最小为27.3 W·m^(-2).

Based on hourly surface ozone measurements and meteorological data in 2015,the temporal-spatial distributions of ozone concentration in Guangzhou and its relationship with meteorological factors are analyzed.The results show that,（1）the ozone concentration in suburban area is higher than that in downtown;（2）the ground level ozone concentration exhibit clear monthly variations,in which highest occurs in September,whereas the lowest occurs in December;The diurnal pattern of ozone shows a single peak mode.From 7 am to 8 am,the ozone concentration is the lowest,while 3 pm is the highest;Ozone concentration is positively correlated with temperature.When the temperature is higher than 30℃,ozone concentration increased significantly.However,ozone concentration was negatively correlated with RH;When the RH was higher than 60%,ozone concentration decreased significantly;When the pressure is lower than 1010 h Pa,ozone concentration is negatively correlated with pressure.When pressure is higher than 1010 h Pa,ozone is positively correlated with pressure.When the wind scale approaches 2-3,ozone concentration is relatively high.In terms of wind direction,the ozone concentration is highest when wind is WNW to WSW,suggesting an ozone contribution from the west of Guangzhou.In terms of solar intensity,ozone concentration turned out to be the highest in the sunny days,followed by cloudy days,and then rainy days.In general,high temperature,long sunshine,strong radiation,low air pressure,low humidity and wind speed are the main meteorological factors associated with high ozone concentration in Guangzhou.When the concentration of ozone exceeds 200 μg·m^-3,the corresponding meteorological conditions are：temperature,25.9-37.4 ℃;relative humidity,29%-83%;atmospheric pressure,989.4-1009.1 h Pa;wind speed,0.7-5.8 m·s^-1.The minimum of diurnal maximum UV radiation intensity is 32.6 W·m^-2,and the minimum of 10：00-14：00 average is 27.3 W·m^-2.