Meteorological Causes of Boundary-layer Ozone Surge in September 2022 over Shaowu of Fujian Province
Using the multi-source observation data and the methods such as weather classification,statistical synthesis,and physical quantity diagnosis,this article explores the characteristics of abnormal increase of O3 in the boundary layer and the comprehensive application of atmospheric thermodynamics in September 2022 at Shaowu Station of Fujian Province(a National Meteorological Sounding Station and O3 Sounding Observation Scientific Experimental Base)so as to reveal the causes for the abnormal increase of O3 in the boundary layer and the mechanism of the influence of atmospheric thermodynamic and dynamic conditions on it.The results show that in September 2022,the near-surface daily maximum 8 h average ozone concentrations(O3-8h)in Shaowu increased by 125.4％at most compared to the long-term(2015-2021)mean.Particularly,during the non-photochemical period from 21 o'clock to the next 7 o'clock,the O3-1h concentration rose by 137.1％.The boundary layer O3 volumetric mixture ratio(OVMR)surpassed the seasonal average significantly,and the observed total ozone column on September 21 reached its maximum in the same layer throughout the year.The surge in O3 level primarily resulted from the combination effects of subtropical high-pressure systems and the peripheries of three typhoons during September 2022,which led to a noticeable rise in solar radiation,reduced cloud cover,rising surface temperature,lowered relative humidity,and less precipitation as well as long-lasting strong northerly winds.The high O3 level of boundary layer on the 7th and the 21st occurred under a stable atmospheric stratification with dry air and thin moist layer.In the meantime,the value of downward convective available potential energy(DC APE)was relatively high,ranging from 200 to 800 J·kg-1,and the easterly winds prevailed in the lower levels at speed of 4～8 m·s-1.To sum up,the configuration of meteorological elements and the thermodynamic and dynamic conditions are favorable for the photochemical production of O3,and also favorable for the horizontal transport of O3-rich air from upwind areas and the downward intrusion of O3 into the boundary layer.The latter is the main contributor to the anomalous increase in near-surface O3 concentration.
Ozone soundingdiurnal cycle of O3_1htotal ozone columnmeteorological causesShaowu of Fujian Province
NETL
NSTL
万方数据
