Abstract The global distribution of aerosol optical depth (AOD) is simulated using an aerosol transport model coupled to an atmospheric general circulation model with high spatial and temporal resolution. Daily representative AOD from model simulation is estimated after consideration of observation sampling in daytime (ground-based) and overpass time (satellite) after cloud masking. Large deviations in AOD are found after considering temporally inhomogeneous sampling, with positive differences over desert regions and negative differences over anthropogenic pollution and biomass burning regions. Mean difference in daily AOD of 5.33% (standard deviation of 8.02%), because of temporal inhomogeneous sampling, is identified based on observation time information from the Moderate-Resolution Imaging Spectroradiometer (MODIS). Relative differences in AOD of >50% and >30% were found in 7.9% and 22.8% of the data, respectively. Based on the observation time information from the AERONET, relative root mean square error (rRMSE) of AOD due to temporal inhomogeneous sampling is estimated to be 4.30–18.66%. After correcting for temporal sampling inhomogeneity, the simulated global AOD was compared with AODs from MODIS and AERONET. The simulated AOD becomes lower than MODIS AOD because of emission and transport discrepancies related to dust, a limited accounting of nitrate processes, and limitation errors from MODIS AOD retrieval. A regional positive bias in SPRINTARS AOD was found in biomass burning regions, which is due to transport pattern errors related to the initial injection height of emissions. A weak correlation is found over the regions with multiple aerosol sources because of complex interactions of individual aerosol types.

中文翻译：

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MIROC-SPRINTARS 观测和模拟之间气溶胶光学深度的比较：时间不均匀采样的影响

摘要 使用气溶胶传输模型与具有高时空分辨率的大气环流模型耦合，模拟气溶胶光学深度 (AOD) 的全球分布。模型模拟的每日代表性 AOD 是在考虑云掩蔽后白天（地面）和立交桥时间（卫星）的观测采样后估算的。在考虑时间不均匀采样后发现 AOD 存在较大偏差，沙漠地区存在正差异，人为污染和生物量燃烧地区存在负差异。由于时间不均匀采样，每日 AOD 的平均差异为 5.33%（标准偏差为 8.02%），这是根据来自中分辨率成像光谱仪 (MODIS) 的观测时间信息确定的。分别在 7.9% 和 22.8% 的数据中发现 AOD 的相对差异 >50% 和 >30%。根据来自 AERONET 的观测时间信息，由于时间不均匀采样导致的 AOD 相对均方根误差 (rRMSE) 估计为 4.30-18.66%。在对时间采样不均匀性进行校正后，将模拟的全局 AOD 与来自 MODIS 和 AERONET 的 AOD 进行比较。由于与粉尘相关的排放和传输差异、硝酸盐过程的有限计算以及 MODIS AOD 检索的限制误差，模拟的 AOD 变得低于 MODIS AOD。在生物质燃烧区域发现 SPRINTARS AOD 的区域正偏差，这是由于与排放初始注入高度相关的传输模式错误。