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姜玉洁, 张玲, 朱寿鹏, 等. 2023. 冬春两湖盆地地区大气气溶胶污染的年代际变化特征及其与东亚经向风南北反相位的联系[J]. 大气科学, 48(X): 1−16. doi: 10.3878/j.issn.1006-9895.2212.22179
引用本文: 姜玉洁, 张玲, 朱寿鹏, 等. 2023. 冬春两湖盆地地区大气气溶胶污染的年代际变化特征及其与东亚经向风南北反相位的联系[J]. 大气科学, 48(X): 1−16. doi: 10.3878/j.issn.1006-9895.2212.22179
JIANG Yujie, ZHANG Ling, ZHU Shoupeng, et al. 2023. Characteristics of Interdecadal Variability in Atmospheric Aerosol Pollution in the Twain-Hu Basin Region in Winter and Spring and Its Association with North–South Antiphase Modes of Meridional Winds in East Asia [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 48(X): 1−16. doi: 10.3878/j.issn.1006-9895.2212.22179
Citation: JIANG Yujie, ZHANG Ling, ZHU Shoupeng, et al. 2023. Characteristics of Interdecadal Variability in Atmospheric Aerosol Pollution in the Twain-Hu Basin Region in Winter and Spring and Its Association with North–South Antiphase Modes of Meridional Winds in East Asia [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 48(X): 1−16. doi: 10.3878/j.issn.1006-9895.2212.22179

冬春两湖盆地地区大气气溶胶污染的年代际变化特征及其与东亚经向风南北反相位的联系

Characteristics of Interdecadal Variability in Atmospheric Aerosol Pollution in the Twain-Hu Basin Region in Winter and Spring and Its Association with North–South Antiphase Modes of Meridional Winds in East Asia

  • 摘要: 基于MERRA-2及ERA5逐月再分析资料,本文采用EOF分析、线性回归和合成分析等方法,分析了1980~2020年长江流域中游两湖盆地地区气溶胶光学厚度(AOD)的年代际变化特征及东亚经向风南北反位相模态对其的影响。结果表明,在年代际尺度上两湖盆地地区AOD呈现非线性的变化趋势,20世纪80、90年代处于低值,21世纪初AOD持续升高,2010年后开始下降。空间场上表现为全区一致的变化特征,高值区主要位于两湖盆地中部,以洞庭湖为中心呈南北纵向分布。进一步对两湖盆地AOD年代际变化与大气环流异常关系的分析表明,在东亚经向风南北反相模的影响下,偏北风输送是影响两湖盆地AOD年代际变化的主要气象原因。在年代际尺度上,当西伯利亚高压的强度、面积增大,东亚大槽西移,西北太平洋副热带高压脊线南移时,东亚经向风南北反相模趋于正相位(即长江以北有异常偏南风、长江以南有异常偏北风)。此时,两湖盆地位于气旋性环流异常的底部,在异常的偏北风的作用下,西北地区的气溶胶向两湖盆地输送加强。且两湖盆地处于两个异常气旋性环流的中间,气压梯度小,风速偏弱,使得两湖盆地气溶胶输入大于输出,促进21世纪初AOD年代际升高。

     

    Abstract: Based on MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications) and ERA5 (Fifth major global reanalysis produced by ECMWF) monthly reanalysis data, EOF (Empirical Orthogonal Function) analysis, linear regression, and composite analysis are used to analyze the interdecadal variation characteristics of AOD (aerosol optical depth) in the Twain-Hu Basin in the middle reaches of the Yangtze River basin during 1980–2020 and influence of the north–south antiphase mode of meridional wind in East Asia. The results show that AOD in the Twain-Hu Basin region shows a nonlinear trend on the interdecadal scale, exhibiting low AOD values in the 1980s and 1990s, a continuous increase at the beginning of the 21st century, and a decline after 2010. The spatial performance is characterized by a consistent variation across the study region, and high-value areas are mainly located in the middle of the Twain-Hu Basin, with Dongting Lake being the center in a north–south longitudinal distribution. Further analysis of the relationship between the interdecadal variation in AOD and anomalous atmospheric circulation in the Twain-Hu Basin indicates that northerly wind transportation under the influence of the north–south antiphase mode of meridional winds in East Asia is the main meteorological cause of interdecadal variations in AOD in the Twain-Hu Basin. On the interdecadal scale, when the intensity and area of the Siberian high pressure increase, the East Asian trough shifts westward, and the western Pacific subtropical high shifts southward, the north–south antiphase mode of the meridional winds in East Asia tends to be in a positive phase (i.e., there are anomalous southerly winds to the north of the Yangtze River and anomalous northerly winds to the south of the Yangtze River). Under this positive phase, the Twain-Hu Basin is located at the bottom of anomalous cyclonic circulation; hence, anomalous northerly winds enhance aerosol transport to the Twain-Hu Basin. Moreover, the Twain-Hu Basin is located in the middle of two anomalous cyclonic circulations, resulting in a small pressure gradient and weak wind speed. Therefore, the aerosol input in the Twain-Hu Basin is larger than the output, enhancing the interdecadal increase in AOD in the early 21st century.

     

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