Abstract Irradiance and LiDAR measurements at the surface combined with satellite products from SEVIRI (Spinning Enhanced Visible and InfraRed Imager) and MODIS (MODerate resolution Imaging Spectroradiometer) were used to detect and characterize the Etna volcano (Italy) plume that crossed southeastern Italy on 3 December 2015, from about 10:00 up to 11:30 UTC, and estimate its radiative impact. The volcanic plume was delivered by a violent and short paroxysmal eruption that occurred from 02:30 to 03:10 UTC of 3 December 2015, about 400 km away from the monitoring site. Measurements from the LiDAR combined with model results showed that the aerosol optical depth of the volcanic plume, located from about 11 to 13 km above sea level (asl), was equal to 0.80 ± 0.07 at 532 nm. A low tropospheric aerosol load, located up to about 7 km asl, with optical depth equal to 0.19 ± 0.01 at 532 nm was also revealed by the LiDAR measurements. Short-Wave (SW) downward and upward irradiance measurements revealed that the instantaneous SW direct radiative forcing at the surface (DRFsurf) decreased to −146 ± 16 W m−2 at 10:50 UTC because of the volcanic plume passage. A Two-Stream radiative transfer model integrated with experimental measurements, which took into account the volcanic plume and the low tropospheric aerosol properties, was used to reproduce the SW radiative flux measurements at the surface and estimate the aerosol DRF both at the top of the atmosphere (TOA) and at the surface, in addition to the aerosol heating rate vertical profile. We found that the clear-sky, instantaneous, SW DRF at the TOA and the atmospheric forcing were equal to −112 and 33 W m-2, respectively, at 10:50 UTC that represented the time at which the volcanic plume radiative impact was the highest. The SW aerosol heating rate reached the peak value of 1.24 K day−1 at 12 km asl and decreased to −0.06 K day−1 at 11 km asl, at 10:50 UTC. The role of the aerosol load located up to about 7 km asl and the corresponding radiative impact has also been evaluated.

中文翻译：

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2015 年 12 月 3 日埃特纳火山气溶胶对意大利东南部的辐射影响

摘要 表面的辐照度和 LiDAR 测量值结合 SEVIRI（旋转增强型可见光和红外成像仪）和 MODIS（中分辨率成像光谱仪）的卫星产品，用于检测和表征 12 月 3 日穿越意大利东南部的埃特纳火山（意大利）羽流。 2015，从大约 10:00 到 11:30 UTC，并估计其辐射影响。火山羽是由 UTC 时间 2015 年 12 月 3 日 02:30 至 03:10 发生的猛烈短暂的阵发性喷发造成的，距离监测点约 400 公里。来自 LiDAR 的测量结合模型结果表明，位于海拔约 11 至 13 公里（asl）的火山羽流的气溶胶光学深度在 532 nm 处等于 0.80 ± 0.07。一个低的对流层气溶胶载荷，位于距地球近 7 公里处，LiDAR 测量还揭示了在 532 nm 处光学深度等于 0.19 ± 0.01 的情况。短波 (SW) 向下和向上辐照度测量显示，由于火山羽流通道，地表瞬时 SW 直接辐射强迫 (DRFsurf) 在 UTC 时间 10:50 降低至 -146 ± 16 W m-2。双流辐射传输模型与实验测量相结合，考虑了火山羽流和低对流层气溶胶特性，用于重现表面的 SW 辐射通量测量值，并估计大气顶部的气溶胶 DRF (TOA) 和在地表，除了气溶胶加热速率垂直剖面。我们发现 TOA 处的晴空、瞬时、SW DRF 和大气强迫分别等于 -112 和 33 W m-2，在 10：50 UTC，代表火山羽流辐射影响最高的时间。SW 气溶胶加热速率在 12 km asl 达到峰值 1.24 K day-1，并在 UTC 时间 10:50 在 11 km asl 下降到 -0.06 K day-1。还评估了高达约 7 公里的气溶胶载荷的作用以及相应的辐射影响。