南京地区近地面臭氧浓度与气象条件关系研究

通过分析2013—2015年南京地区相关气象要素对近地面臭氧浓度的影响,建立了用于不同季节高浓度臭氧污染事件的预报预警模型,并归纳总结了南京地区高浓度臭氧出现的天气形势.结果表明,近地面臭氧浓度的变化与气象要素密切相关,气温、能见度、日照小时、总(净)辐射辐照度等要素与O_3浓度呈显著正相关,与相对湿度、总(低)云量呈负相关.高浓度臭氧污染是多因子综合作用的结果,典型气象条件表现为:太阳辐射强,低云量少,相对湿度适宜,地面小风速及特定的风向.通过定义高浓度臭氧潜势指数HOPI和风向指数WDI,并综合考虑14:00地面气温、相对湿度及8:00各标准层的相关气象要素,建立了逐季节多指标叠套的高浓度臭氧预报方程.采用2016年资料对其进行检验,发现预报值与观测值的相关系数分别达0.72(冬季)、0.76(春季)和0.73(夏季),说明方程具有较好的拟合效果和可预报性.通过普查历史天气图,归纳了伴随南京地区高浓度臭氧事件出现的8种主要天气形势,即高压类(高压中心G0、高压后部G1)、低压类(低压底部D0、低压前部D1、低压倒槽D2)、均压类(高压相关的均压JG、低压相关的均压JD、其它均压J).其中,以高压后部地面形势出现概率最大,低压前部均压场出现时对应臭氧平均浓度最高.

Study on the relationship between surface ozone concentrations and meteorological conditions in Nanjing, China

The seasonal high-concentration ozone events forecasting models are established, by the analyzing of meteorological factors impacts on the surface ozone concentrations during 2013-2015 in Nanjing, China, and the related high-concentration ozone synoptic situations are also summarized. The results showed that the variation of surface ozone concentration is closely related to meteorological conditions. The temperature, visibility, sunshine hours, and total (net) irradiance had significant positive correlation with O₃ concentration. Relative humidity (RH), and the total (low) cloud amount was negatively related to O₃ concentrations. High concentration ozone pollution is influenced by comprehensive factors and results of typical meteorological conditions such as strong solar radiation, low cloud amount, suitable RH and low-wind speed with specific directions. Through the definition of high concentration ozone potential index (HOPI) and wind direction index (WDI), and considering the surface temperature, and RH at 14:00 with weather factors from the standard layers at 8:00, a multi-index-nested prediction equation for seasonal high-concentration ozone is established. The prediction equation was tested using the related data of 2016, the results showed that the correlation coefficients between the predicted value and the observed value was 0.72 (winter), 0.76 (spring) and 0.73 (summer), and the prediction equation has good fitting effects and accurate predictability. By analyzing the historical weather situations, 8 types main synoptic situations with high-concentration O₃ in Nanjing are summed up, namely high pressure (high pressure center G0, rear of high pressure G1), low pressure (bottom of low pressure D0, front of low pressure D1, inverted trough with low pressure D2), equalized pressure (equalized pressure field related to high pressure JG, equalized pressure field related to low pressure JD and other equalized pressure field J). The G1 situation is most common, and the JD situation appears with highest average ozone concentration.