Abstract Aerosols affect global as well as regional climate by interacting with solar radiations and by altering the cloud properties. Due to the scarcity of ground observations over entire India, especially over Indo-Gangetic Plains (IGP), satellite-based measurements provide better spatial and temporal coverage for the evaluation of aerosol optical properties. This study presents the inter-comparison of multiple satellites (MISR, MODIS, and OMI) and ground-based aerosol optical depth (AOD) for the 2010–2017 (8 years) period over IGP (Gandhi College, Jaipur, and Kanpur) region. Satellite observations are spatially and temporally collocated by an average of 50 × 50 km square box and ±30 minutes, respectively. Results indicate a higher correlation with MODIS (R2 = 0.7 at Gandhi College) followed by MISR and OMI AOD. Irrespective of few observations (219) at Jaipur, MISR shows the highest percentage (58%) of data points within the error envelope because of multiple angle viewing and spectral capability gives the accurate information in high reflecting desert areas. MISR and OMI have a systematic negative bias trend for higher AOD at all test sites, while MODIS has a negative bias over the Jaipur region only. The temporal analysis reveals the higher concentration of fine mode aerosols captured by MISR and MODIS in December month over Gandhi College and Kanpur region, whereas Jaipur is over-loading with coarser aerosols during April to June month from the Thar Desert and Middle East dust storms. Seasonal distribution over the IGP region indicates higher AOD in summer owing to dust storms. Inter-comparison shows that MODIS has higher seasonal AOD as compared to MISR. The spatial correlation between MODIS and MISR is high during the summer and winter seasons. The OMI sensor performance over the IGP region has not been found to match with existing patterns. These findings are useful in the context of selecting the most reliable satellite AOD products for future studies.

中文翻译：

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印度地区多卫星和 Aeronet AOD 的比对

摘要 气溶胶通过与太阳辐射相互作用和改变云特性来影响全球和区域气候。由于整个印度，尤其是印度恒河平原 (IGP) 的地面观测稀缺，基于卫星的测量为气溶胶光学特性的评估提供了更好的空间和时间覆盖范围。本研究介绍了 2010-2017 年（8 年）期间 IGP（甘地学院、斋浦尔和坎普尔）地区多颗卫星（MISR、MODIS 和 OMI）和地基气溶胶光学深度 (AOD) 的相互比较. 卫星观测在空间和时间上分别以平均 50 × 50 km 的方格和 ±30 分钟的范围配置。结果表明与 MODIS 的相关性更高（甘地学院的 R2 = 0.7），其次是 MISR 和 OMI AOD。尽管斋浦尔的观测很少 (219)，但由于多角度观察和光谱能力在高反射沙漠地区提供准确信息，因此 MISR 显示误差包络内数据点的百分比最高 (58%)。MISR 和 OMI 在所有测试站点都具有较高的 AOD 的系统性负偏差趋势，而 MODIS 仅在斋浦尔地区具有负偏差。时间分析显示，MISR 和 MODIS 在 12 月在甘地学院和坎普尔地区捕获的细模式气溶胶浓度较高，而斋浦尔在 4 月至 6 月期间因塔尔沙漠和中东沙尘暴而超载了较粗的气溶胶。IGP 地区的季节性分布表明，由于沙尘暴，夏季 AOD 较高。相互比较表明，与 MISR 相比，MODIS 具有更高的季节性 AOD。MODIS 和 MISR 之间的空间相关性在夏季和冬季都很高。尚未发现 IGP 区域上的 OMI 传感器性能与现有模式匹配。这些发现有助于为未来的研究选择最可靠的卫星 AOD 产品。