夏季南亚高压对其邻近UTLS区域臭氧分布的影响

Influence of South Asia high on ozone in the UTLS region during summer

利用欧洲中期数值预报中心(ECMWF)提供的ERA5高分辨率月平均再分析资料,分析了1991—2020年共30 a夏季6—8月南亚高压对其邻近上对流层—下平流层区域臭氧(O 3)分布的影响。结果表明:ERA5资料能清晰地刻画出南亚高压夏季6—8月的月变化及振荡特征,同时能很好地反映出对应的臭氧低值这一现象。此外,ERA5高分辨率资料还能揭示出臭氧低值的范围和强度变化与南亚高压的范围和强度变化之间存在紧密联系。当南亚高压异常偏强(弱)时,邻近区域的臭氧低值增强(减弱),当南亚高压中心位置发生振荡时,臭氧浓度纬向偏差的中心也随之发生变化,这种变化在南亚高压偏强年时更明显。但这种联系有一定复杂性,不同月份的相关性存在差异。南亚高压对臭氧浓度的这种影响主要与对流层的空气输送有关,臭氧低值中心位置和范围的变化与位涡低值、位温纬向偏差负值区域分布相对应。

Based on the ERA5 high-resolution monthly average reanalysis data provided by the European Centre for Medium-Range Weather Forecasts(ECMWF),the influence of the South Asia High(SAH)on the ozone distribution in the upper troposphere and lower stratosphere during June to August in summer for 30 years from 1991 to 2020 was analyzed.Results show that the ERA5 data can clearly depict the monthly variation and oscillation characteristics of SAH from June to August,and also can well reflect the corresponding low ozone values as a recognized phenomenon.Furthermore,ERA5 data can also reveal a strong link between the range and intensity variation of ozone lows and SAH.When the SAH is anomalously strong(weak),the ozone lows in the neighboring areas strengthen(weaken),and when the center of the SAH oscillates,the low center of the ozone zonal deviation also changes,and this change is more pronounced when the SAH is strong.However,this connection is complex and its correlation varies from month to month.The effect of SAH on ozone concentration is mainly related to the air transport in the troposphere,and the location and extent of the low center of ozone corresponds to the low region of the potential vorticity and the negative values of the potential temperature zonal deviation.