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首页> 外文期刊>Atmospheric Chemistry and Physics Discussions >Ozone variability induced by synoptic weather patterns in warm seasons of 2014–2018 over the Yangtze River Delta region, China
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Ozone variability induced by synoptic weather patterns in warm seasons of 2014–2018 over the Yangtze River Delta region, China

机译：2014 - 2018年温暖季节在长江三角洲地区温暖季节概要臭氧变异性

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Ozone (O 3 ) pollution is of great concern in the Yangtze River Delta (YRD) region of China, and the regional O 3 pollution is closely associated with dominant weather systems. With a focus on the warm seasons (April–September) from 2014 to 2018, we quantitatively analyze the characteristics of O 3 variations over the YRD, the impacts of large-scale and synoptic-scale circulations on the O 3 variations and the associated meteorological controlling factors, based on observed ground-level O 3 and meteorological data. Our analysis suggests an increasing trend of the regional mean O 3 concentration in the YRD at 1.8?ppb per year over 2014–2018. Spatially, the empirical orthogonal function analysis suggests the dominant mode accounting for 65.7?% variation in O 3 , implying that an increase in O 3 is the dominant tendency in the entire YRD region. Meteorology is estimated to increase the regional mean O 3 concentration by 3.1?ppb at most from 2014 to 2018. In particular, relative humidity (RH) plays the most important role in modulating the inter-annual O 3 variation, followed by solar radiation (SR) and low cloud cover (LCC). As atmospheric circulations can affect local meteorological factors and O 3 levels, we identify five dominant synoptic weather patterns (SWPs) in the warm seasons in the YRD using the t -mode principal component analysis classification. The typical weather systems of SWPs include the western Pacific Subtropical High (WPSH) under SWP1, a continental high and the Aleutian low under SWP2, an extratropical cyclone under SWP3, a southern low pressure and WPSH under SWP4 and the north China anticyclone under SWP5. The variations of the five SWPs are all favorable to the increase in O 3 concentrations over 2014–2018. However, crucial meteorological factors leading to increases in O 3 concentrations are different under different SWPs. These factors are identified as significant decreases in RH and increases in SR under SWP1, 4 and 5, significant decreases in RH, increases in SR and air temperature (T2) under SWP2 and significant decreases in RH under SWP3. Under SWP1, 4 and 5, significant decreases in RH and increases in SR are predominantly caused by the WPSH weakening under SWP1, the southern low pressure weakening under SWP4 and the north China anticyclone weakening under SWP5. Under SWP2, significant decreases in RH, increases in SR and T2 are mainly produced by the Aleutian low extending southward and a continental high weakening. Under SWP3, significant decreases in RH are mainly induced by an extratropical cyclone strengthening. These changes in atmospheric circulations prevent the water vapor in the southern and northern sea from being transported to the YRD and result in RH significantly decreasing under each SWP. In addition, strengthened descending motions (behind the strengthening trough and in front of the strengthening ridge) lead to decreases in LCC and significant increases in SR under SWP1, 2, 4 and 5. The significant increases in T2 would be due to weakening cold flow introduced by a weakening continental high. Most importantly, the changes in the SWP intensity can make large variations in meteorological factors and contribute more to the O 3 inter-annual variation than the changes in the SWP frequency. Finally, we reconstruct an empirical orthogonal function (EOF) mode 1 time series that is highly correlated with the original O 3 time series, and the reconstructed time series performs well in defining the change in SWP intensity according to the unique feature under each of the SWPs.
机译：臭氧（o 3）污染在中国长三角（YRD）地区非常关注，区域O 3污染与主导天气系统密切相关。从2014年到2018年的温暖季节（4月至9月），我们定量分析了yrd上的o 3变化的特点，大规模和概要循环对O 3变异和相关气象的影响基于观察到的地层O 3和气象数据的控制因素。我们的分析表明，2014 - 2018年，yrd在yrd中的额外趋势率为3.8的浓度为1.8磅。在空间上，经验正交函数分析表明，优势模式占O 3的65.7？％变化，这意味着o 3的增加是整个YRD区域的主导倾向。估计气象学将区域平均值浓度增加3.1〜2018年至2018年。特别是，相对湿度（RH）在调制年度o 3变异方面发挥着最重要的作用，其次是太阳辐射（ SR）和低云盖（LCC）。随着大气循环可能影响局部气象因素和O 3级，我们使用T-MODE主成分分析分类，在YRD中的温暖季节中确定五个主导的舞蹈天气模式（SWPS）。 SWP的典型天气系统包括SWP1下的西太平洋亚热带高（WPSH），在SWP2下，在SWP3下，SWP3，SWP4下的南部低压和WPSH下的含有滋养旋风分离器和SWP5下的WPSH。五种SWP的变化都有利于2014 - 2018年o 3浓度的增加。然而，在不同的SWPS下，导致O 3浓度增加的关键气象因素是不同的。这些因子被鉴定为RH中的显着降低，SWP1,4和5下的SR增加，RH的显着降低，SR在SWP2下的SR和空气温度（T2）增加，SWP3下的RH值显着降低。在SWP1,4和5下，RH的显着降低，SR的增加主要是由SWP1下的WPSH弱化引起的，SWP4下的Southern低压减弱和SWP5下的华北抗岩弱化。在SWP2下，RH的显着降低，SR和T2的增加主要由Aleutian低延伸和大陆高弱化产生。在SWP3下，主要通过潜水旋风分离器强化诱导重量的显着降低。大气循环中的这些变化防止了南部和北海的水蒸气被运输到YRD，并导致每种SWP下的RH显着降低。另外，加强的下降动作（在加强槽的前后）导致LCC的降低，SWP1,2,4和5下SR的显着增加。T2的显着增加是由于弱冷流动由弱化大陆高。最重要的是，SWP强度的变化可以对气象因素进行大的变化，并且比SWP频率的变化更改为O 3年间变化。最后，我们重建了与原始O 3时间序列高度相关的经验正交函数（EOF）模式1时间序列，并且重建的时间序列在定义根据每个下面的唯一特征SWPS。

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