基于差分吸收激光雷达和数值模式探测杭州夏季臭氧分布

为获取杭州市夏季臭氧浓度时空分布特征和气象要素对臭氧浓度的影响,利用臭氧差分吸收激光雷达开展观测,同时利用WRF-Chem模式模拟臭氧时空特征和气象要素。实验结果表明:臭氧浓度模拟结果与激光雷达的观测结果具有很好的一致性。2016年夏季,杭州市18天内发生了4次臭氧重污染,每次持续2到5天,最高浓度达550nL/L。高空1~2km存在较高浓度的臭氧污染层,并存在垂直和水平传输,对近地面臭氧污染有明显影响。近地面臭氧浓度平均最低值出现在凌晨2时左右,为75nL/L;平均浓度最高值在中午12时左右出现,为90nL/L。近地面臭氧浓度的日变化明显,而高空的臭氧浓度日变化不明显。臭氧差分吸收激光雷达系统对臭氧时空分布的探测是可靠的。强太阳辐射、高温、低湿都是臭氧污染形成的有利环境条件,而强风对局地臭氧有扩散作用,降雨对臭氧有很好的消除作用。

Differential absorption lidar combined with numerical model used for detecting distribution of ozone during summer in Hangzhou

An ozone differential absorption lidar (DIAL) was used to carry out observations of the spatial and temporal distribution of summer ozone concentrations in Hangzhou, China, and to study how they are influenced by meteorological elements. The WRF-Chem model was used to simulate the characteristics of the ozone distribution, and for the analysis of meteorological factors. The simulated values for ozone concentration were in good agreement with the observed values obtained using the DIAL. In the summer of 2016, ozone pollution occurred on four occasions in 18 days, with each occasion lasting between two to five days, and with the highest concentration of 550 nL/L detected. There was a highly concentrated ozone layer at an altitude of one to two km, with vertical and horizontal movement having a significant influence on the ozone pollution near the ground. The lowest mean value of ozone concentration near the ground was 75 nL/L, which occurred around 2:00 am, while the average highest value was 90 nL/L, which occurred at 12:00 am. The daily ozone concentration near ground level exhibited diurnal variation, a pattern not apparent in the upper air. The DIAL system was reliable for the detection of ozone. Conditions of strong solar radiation, high temperature, and low humidity were seen as being conducive to the formation of ozone, while strong winds and rain had a diffusing effect.