The key factors affecting the variation of the ‘ozone valley’, which appears during the boreal summer in the upper troposphere and lower stratosphere (UTLS) over the South Asian High (SAH) and its adjacent areas, have not been determined. This study has performed statistical analysis to improve the understanding of the roles of the sea surface temperature (SST), tropopause height, and the West Pacific Subtropical High (WPSH) on the ozone valley. Based on the European Center for Medium-Range Weather Forecasts Interim Re-Analysis (ERA5), Modern Era Retrospective Analysis for Research and Applications dataset version 2 (MERRA2), and the Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) observation dataset, we examined the principal components of the zonal deviation of the total column ozone (TCO*) in the UTLS by applying the empirical orthogonal function (EOF), Liang-Kleeman information flow method, regression analysis, and composite analysis. The variations of the TCO* anomalies show three dominant modes, namely the east-west dipole mode in the low latitude region, the east-west tripole mode in the middle latitude region, and the south-north mode. According to the regression analysis and information flow, the three leading principal components of TCO* variations are related to the SST near Indonesia and the western Pacific Ocean in low latitudes, the tropopause height over the Iranian Plateau (IP), and the strength of the SAH over the eastern part of the Tibetan Plateau (TP), which is linked to the synchronousness between the SAH and the WPSH. For the east-west dipole mode in the low latitude region, composite analysis shows the interaction between the atmosphere and ocean causes the strengthening of the southern trough at 850 hPa and the divergence at 200 hPa, resulting in a decrease of the TCO* in the UTLS near the low latitude region around the TP. For the east-west tripole mode in the middle latitude region, the composite analysis shows obvious negative anomalies over the IP, where the TCO* reduces and the extent of the ozone valley over the IP increases with the rise of the tropopause. Comparatively, the south-north mode shows obvious positive anomalies over the TP, where the TCO* increases and the extent of the ozone valley over the TP decreases with a weak SAH. This mode is closely related to the location of the WPSH. In summary, the leading factors affecting the three dominant modes for the variations of the TCO* anomalies are SST, tropopause height, and the WPSH.

尚未确定影响“臭氧谷”变化的关键因素，该变化出现在北亚夏季高压对流层和低空平流层（UTLS）的北半球夏季，在北亚夏季高压和邻近地区。这项研究进行了统计分析，以增进对海平面温度（SST），对流层顶高度和臭氧谷上西太平洋副热带高压（WPSH）作用的了解。基于欧洲中型天气预报中心临时重新分析（ERA5），研究和应用数据集版本2（MERRA2）的现代时代回顾性分析以及同温层水和臭氧卫星均质化（SWOOSH）观测数据集，我们通过应用经验正交函数（EOF），Liang-Kleeman信息流方法，回归分析和复合分析，研究了UTLS中总柱状臭氧（TCO *）区域偏差的主要成分。TCO *异常的变化表现出三种主要模式，即低纬度地区的东西向偶极子模式，中纬度地区的东西方三极子模式和南北模式。根据回归分析和信息流，TCO *变化的三个主要成分与印度尼西亚和西太平洋低纬度附近的海温，伊朗高原（IP）上的对流层顶高度以及海平面的强度有关。青藏高原东部的SAH与SAH和WPSH之间的同步性有关。对于低纬度地区的东西向偶极子模式，综合分析表明，大气与海洋之间的相互作用导致了850 hPa南部海槽的加强和200 hPa处的发散，导致TCO *的降低。 TP周围低纬度区域附近的UTLS。对于中纬度地区的东西三向模式，综合分析显示出IP上存在明显的负异常，随着对流层顶的上升，TCO *减小，IP上的臭氧谷范围增加。相比之下，南北模式在TP上显示出明显的正异常，其中TCO *增大，而在TP上的臭氧谷减小，且SAH弱。此模式与WPSH的位置紧密相关。综上所述，