Aerosol Indices Derived from MODIS Data for Indicating Aerosol-Induced Air Pollution
Aerosol Indices Derived from MODIS Data for Indicating Aerosol-Induced Air Pollution
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DOI：
10.3390/rs6021587
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发表时间：
2014-02
期刊：
影响因子：
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通讯作者：
Junliang He;Y. Zha;Jiahua Zhang;Jay Gao
中科院分区：
文献类型：
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作者：
Junliang He;Y. Zha;Jiahua Zhang;Jay Gao
气溶胶光学深度（AOD）是估算大气中气溶胶浓度、评估大气污染严重程度以及研究其对气候影响的关键变量。在本研究中，借助 6S 辐射传输模型，我们模拟了每个中分辨率成像光谱辐射计 (MODIS) 波段中与 AOD 相关的表观反射率。关系的紧密程度用于识别最敏感和最不敏感的 MODIS 波段。然后使用这两个波段构建三个气溶胶指数（差值、比率和归一化差值），以快速有效地估计 AOD。这三个指数分别与气溶胶机器人网络（AERONET）太湖站、北京站和香河站现场测量的AOD相关。研究发现，蓝色波段（波段3）的表观反射率对AOD最敏感，而中红外波长（波段7）的表观反射率最不敏感。差异气溶胶指数最准确地反映气溶胶引起的大气污染，太湖站相关系数为0.585、0.860、0.685和0.333，北京站相关系数为0.721、0.839、0.795和0.629，北京站相关系数为0.778、0.782、0.837和0.778。香河站春季、夏季、秋季和冬季分别为0.643。结论是，新提出的差异气溶胶指数可以有效地利用 MODIS 卫星图像相对容易地研究气溶胶引起的空气污染水平。
Aerosol optical depth (AOD) is a critical variable in estimating aerosol concentration in the atmosphere, evaluating severity of atmospheric pollution, and studying their impact on climate. With the assistance of the 6S radiative transfer model, we simulated apparent reflectancein relation to AOD in each Moderate Resolution Imaging Spectroradiometer (MODIS) waveband in this study. The closeness of the relationship was used to identify the most and least sensitive MODIS wavebands. These two bands were then used to construct three aerosol indices (difference, ratio, and normalized difference) for estimating AOD quickly and effectively. The three indices were correlated, respectively, with in situ measured AOD at the Aerosol Robotic NETwork (AERONET) Lake Taihu, Beijing, and Xianghe stations. It is found that apparent reflectance of the blue waveband (band 3) is the most sensitive to AOD while the mid-infrared wavelength (band 7) is the least sensitive. The difference aerosol index is the most accurate in indicating aerosol-induced atmospheric pollution with a correlation coefficient of 0.585, 0.860, 0.685, and 0.333 at the Lake Taihu station, 0.721, 0.839, 0.795, and 0.629 at the Beijing station, and 0.778, 0.782, 0.837, and 0.643 at the Xianghe station in spring, summer, autumn and winter, respectively. It is concluded that the newly proposed difference aerosol index can be used effectively to study the level of aerosol-induced air pollution from MODIS satellite imagery with relative ease.