Abstract The aerosol change over the Tibetan Plateau (TP) is poorly understood due to the scarcity of aerosol measurements over the TP. The aerosol optical properties were measured with a CE-318 sun photometer from January to December in 2017 at the Litang station (30.00°N, 100.16°E, 3950.5 m a.s.l.) over the eastern edge of the TP to characterize the variations in the aerosol optical properties and assess the applicability of MODIS AOD products at the eastern edge of TP. The analyses show that the annual mean aerosol optical depth at 440 nm (AOD440nm) is 0.08 ± 0.03. The mean annual Angstrom exponent between 440 and 870 nm (AE440–870nm) is 0.72 ± 0.23. The monthly-averaged AOD440nm exhibits a maximum (0.11 ± 0.04) in July and minimum (0.05 ± 0.02) in January, while the monthly mean AE440–870nm shows a maximum (1.08 ± 0.19) in July and minimum (0.48 ± 0.32) in February. The findings based on measured AOD440nm and AE440–870nm indicate low AOD, dominated by coarse particles in winter and fine particles in summer over the eastern TP edge. Three datasets of MODIS AOD products with 3 km spatial resolution as well as with 10 km spatial resolution based on Dark Target (DT) and Deep Blue (DB) algorithms are validated using the ground-based measurements over the eastern edge of the TP. Although the validations show a low accuracy of MODIS AOD products of the three datasets over this TP region, the MODIS AOD products based on the DB algorithm with 10 km resolution could be used in the atmospheric environment over the eastern edge of the TP based on the best match between AOD data and ground-based measurements, the lowest retrieval error, and the largest percentage falling within the expected error envelope.

中文翻译：

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2017年基于地基遥感的青藏高原东缘气溶胶光学特性变化及MODIS AOD产品验证

摘要 由于青藏高原上空气溶胶测量的稀缺性，人们对青藏高原（TP）上的气溶胶变化知之甚少。2017 年 1 月至 12 月，在青藏高原东部边缘的理塘站（30.00°N，100.16°E，3950.5 m asl）使用 CE-318 太阳光度计测量气溶胶光学特性，以表征气溶胶的变化光学特性并评估 MODIS AOD 产品在青藏高原东部边缘的适用性。分析表明，440 nm (AOD440nm) 处的年平均气溶胶光学深度为 0.08 ± 0.03。440 到 870 nm (AE440–870nm) 之间的年平均埃指数为 0.72 ± 0.23。月平均AOD440nm在7月最大（0.11±0.04），1月最小（0.05±0.02），而月平均AE440-870nm在7月最大（1.08±0.19），最小（0.19）。48 ± 0.32) 在二月。基于测得的 AOD440nm 和 AE440-870nm 的发现表明 AOD 较低，在高原东部边缘以冬季粗颗粒和夏季细颗粒为主。使用青藏高原东部边缘的地面测量验证了基于暗目标 (DT) 和深蓝 (DB) 算法的 MODIS AOD 产品的三个数据集，其空间分辨率为 3 公里，空间分辨率为 10 公里。尽管验证表明该高原地区三个数据集的 MODIS AOD 产品精度较低，但基于分辨率为 10 km 的 DB 算法的 MODIS AOD 产品可用于高原东部边缘的大气环境。 AOD 数据和地面测量之间的最佳匹配，最低的检索误差，