关键词: 污染日, 经验正交函数, 奇异值分解

Abstract:

Using the daily maximum 8-hour moving average values of near-surface ozone concentration data from 2013 to 2020 in the Beijing-Tianjin-Hebei region and concurrent atmospheric reanalysis data, this study employs Empirical Orthogonal Functions (EOF) and Singular Value Decomposition (SVD) techniques to analyze the variations in near-surface ozone concentrations, the typical spatial distribution of ozone modal concentrations, and their relationships with major meteorological factors. The results indicate that the near-surface ozone concentration in the Beijing-Tianjin-Hebei region overall shows an increasing trend, with significant increases noted from 2017 to 2019, exhibiting a spatial distribution pattern of higher concentrations in the south and lower in the north. The first mode of the EOF reveals consistent spatial variability in near-surface ozone concentrations across the region, with the most significant changes observed in the areas around the junctions of Baoding, Shijiazhuang, Hengshui, and Cangzhou. The daily maximum 8-hour moving average values of ozone concentration are positively correlated with the temperature at 15:00 and the meridional wind speed, and negatively correlated with the relative humidity at the same time, with these correlations being most significant in the southern part of the Beijing-Tianjin-Hebei region.

Key words: Pollution day, Empirical Orthogonal Function (EOF), Singular Value Decomposition (SVD)