School of Atmospheric Science, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
Environ Sci Pollut Res Int. 2019 Mar;26(8):7969-7979. doi: 10.1007/s11356-019-04203-4. Epub 2019 Jan 25.
In this study, MODerate resolution Imaging Spectroradiometer (MODIS) Collection 6.1 (C6.1) level-2 Dark Target (DT) Aerosol Optical Depth (AOD) observations at 550 nm (AOD) for the highest quality flag assurance (QA = 3) were obtained to analyze spatiotemporal variations of aerosol optical properties over the Yellow and the Bohai Sea from 2002 to 2017. Spectral AOD observations at 470 nm (AOD) and 660 nm (AOD) were obtained to calculate Angstrom Exponent (AE) and classify the aerosol types including clean continental (CC), clean maritime (CM) biomass and urban industrial (BUI), dust (D), and mixed (MXD) aerosol types. Results showed a very distinct spatial pattern of AOD distribution over the Bohai Sea which looks suspicious, i.e., high aerosol loadings (AOD > 0.8) throughout the entire time period, whereas relative low AOD distribution was observed over the adjacent land pixels especially in autumn and winter, which suggested that the DT algorithm might be influenced by a large number of sediments located in the Bohai Sea. Significant differences in spatial distributions were found in different seasons in terms of area coverage as a maximum number of pixels were available during autumn, and regional high and low aerosol loadings were observed during autumn and summer, respectively. Trend analysis from 2002 to 2017 showed that AOD was increased up to 0.04 over the Bohai Sea and decreased up to 0.04 over the Yellow Sea, and this trend varies from month to month. Aerosol classification showed significant contributions of BUI and CC over the region, and contributions of CM, DUST, and MXD aerosols over the Yellow Sea were relatively high compared to the Bohai Sea.
本研究获取了 2002 年至 2017 年期间 MODerate resolution Imaging Spectroradiometer（MODIS）第六代 1 级暗目标（DT）气溶胶光学厚度（AOD）550nm（AOD）MODIS 数据（最高质量保证等级 QA=3），分析了黄海和渤海地区气溶胶光学特性的时空变化。获取了 470nm（AOD）和 660nm（AOD）的光谱 AOD 观测值，以计算 Angstrom 指数（AE）并对气溶胶类型进行分类，包括清洁大陆（CC）、清洁海洋（CM）生物质和城市工业（BUI）、沙尘（D）和混合（MXD）气溶胶类型。结果表明，渤海上空的 AOD 分布存在非常明显的空间模式，这看起来很可疑，即在整个时间段内，气溶胶负荷（AOD>0.8）都很高，而相邻陆地像素的 AOD 分布相对较低，特别是在秋季和冬季，这表明 DT 算法可能受到渤海大量沉积物的影响。在不同季节，AOD 的空间分布存在显著差异，在秋季，AOD 的分布面积最大，在秋季和夏季，区域高和低气溶胶负荷分别被观测到。2002 年至 2017 年的趋势分析表明，AOD 在渤海增加了约 0.04，在黄海减少了约 0.04，这种趋势逐月变化。气溶胶分类表明，该地区 BUI 和 CC 的贡献显著，与渤海相比，CM、DUST 和 MXD 气溶胶在黄海的贡献相对较高。
